Do build-time bindgen

Majority of build_gecko.rs is just the straightforward conversion from
regen.py. There are two differences that:
1. Side in whitelist is changed to mozilla::Side
2. std::atomic__My_base is added to opaque types for Windows

8 files changed, 739 insertions, 835 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 8a79b8eda44..0f5db66439d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -69,6 +69,14 @@ dependencies = [
 ]
 
 [[package]]
+name = "aster"
+version = "0.34.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "syntex_syntax 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "audio-video-metadata"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -282,6 +290,14 @@ dependencies = [
 ]
 
 [[package]]
+name = "cexpr"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "nom 1.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "cfg-if"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -296,6 +312,16 @@ dependencies = [
 ]
 
 [[package]]
+name = "clang-sys"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glob 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "clippy_lints"
 version = "0.0.98"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1380,6 +1406,26 @@ dependencies = [
 ]
 
 [[package]]
+name = "libbindgen"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aster 0.34.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cexpr 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clang-sys 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quasi 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quasi_codegen 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.76 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "libc"
 version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2068,6 +2114,26 @@ dependencies = [
 ]
 
 [[package]]
+name = "quasi"
+version = "0.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "syntex_errors 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quasi_codegen"
+version = "0.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aster 0.34.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_errors 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.50.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "quickersort"
 version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2601,6 +2667,7 @@ dependencies = [
  "html5ever-atoms 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libbindgen 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "nsstring_vendor 0.1.0",
@@ -2616,6 +2683,7 @@ dependencies = [
  "quickersort 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.76 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.18 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3212,6 +3280,7 @@ dependencies = [
 "checksum angle 0.1.2 (git+https://github.com/servo/angle?branch=servo)" = "<none>"
 "checksum app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "636ee56f12e31dbc11dc0a1ac6004f08b04e6e6595963716fc8130e90d4e04cf"
 "checksum arrayvec 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)" = "80a137392e2e92ce7387c063d98a11f0d47115426c5f8759657af3c7b385c860"
+"checksum aster 0.34.0 (registry+https://github.com/rust-lang/crates.io-index)" = "88bb8ecdf6a7eaddb7bfd872ebf5e085d343ca42ce98c582dba8046e3450b524"
 "checksum audio-video-metadata 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "03da2550cb89fe3faf218c179261c26cf7891c4234707c15f5d09ebb32ae2400"
 "checksum azure 0.9.1 (git+https://github.com/servo/rust-azure)" = "<none>"
 "checksum backtrace 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "346d7644f0b5f9bc73082d3b2236b69a05fd35cce0cfa3724e184e6a5c9e2a2f"
@@ -3230,8 +3299,10 @@ dependencies = [
 "checksum byteorder 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "0fc10e8cc6b2580fda3f36eb6dc5316657f812a3df879a44a66fc9f0fdbc4855"
 "checksum bytes 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c129aff112dcc562970abb69e2508b40850dd24c274761bb50fb8a0067ba6c27"
 "checksum caseless 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b6893f86ac0c9275b5cbba9212ccd71020b447d4c3e2eebad70e1bc47fdd6dfb"
+"checksum cexpr 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "393a5f0088efbe41f9d1fcd062f24e83c278608420e62109feb2c8abee07de7d"
 "checksum cfg-if 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "de1e760d7b6535af4241fca8bd8adf68e2e7edacc6b29f5d399050c5e48cf88c"
 "checksum cgl 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "8bdd78cca65a739cb5475dbf6b6bbb49373e327f4a6f2b499c0f98632df38c10"
+"checksum clang-sys 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)" = "19911f7964ce61a02d382adee8400f919d0fedd53c5441e3d6a9858ba73e249e"
 "checksum clippy_lints 0.0.98 (registry+https://github.com/rust-lang/crates.io-index)" = "4329699b62341fd3ce3ebe13ade6c87d35b8778091e0c2f6da51399e081b9671"
 "checksum cmake 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)" = "dfcf5bcece56ef953b8ea042509e9dcbdfe97820b7e20d86beb53df30ed94978"
 "checksum cocoa 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6d24ed9a15e9c0892cdb20c7acc3e50441501b990ee6dc318c176981829a7941"
@@ -3313,6 +3384,7 @@ dependencies = [
 "checksum lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "49247ec2a285bb3dcb23cbd9c35193c025e7251bfce77c1d5da97e6362dffe7f"
 "checksum leak 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "bd100e01f1154f2908dfa7d02219aeab25d0b9c7fa955164192e3245255a0c73"
 "checksum leaky-cow 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "40a8225d44241fd324a8af2806ba635fc7c8a7e9a7de4d5cf3ef54e71f5926fc"
+"checksum libbindgen 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "6a46e95efa501b2940e9c81dbb727e557b39b41f77f1170aba6eed5a546e9964"
 "checksum libc 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)" = "044d1360593a78f5c8e5e710beccdc24ab71d1f01bc19a29bcacdba22e8475d8"
 "checksum libloading 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "eceb2637ee9a27c7f19764048a9f377e40e3a70a322722f348e6bc7704d565f2"
 "checksum libressl-pnacl-sys 2.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "cbc058951ab6a3ef35ca16462d7642c4867e6403520811f28537a4e2f2db3e71"
@@ -3367,6 +3439,8 @@ dependencies = [
 "checksum pkg-config 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8cee804ecc7eaf201a4a207241472cc870e825206f6c031e3ee2a72fa425f2fa"
 "checksum pnacl-build-helper 1.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "61c9231d31aea845007443d62fcbb58bb6949ab9c18081ee1e09920e0cf1118b"
 "checksum png 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "06208e2ee243e3118a55dda9318f821f206d8563fb8d4df258767f8e62bb0997"
+"checksum quasi 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ab7992920bf5bc5f1ed6fdc49090bf665cd00b3aa4b78c16ac3465286257db1"
+"checksum quasi_codegen 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d52e5e2c92ffdad67a9b86ad27ad999bf1a652723f1d4cc93b7cf6c272b5f8e0"
 "checksum quickersort 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e952ea7699262481636004bc4ab8afaccf2bc13f91b79d1aee6617bd8fc39651"
 "checksum quine-mc_cluskey 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "07589615d719a60c8dd8a4622e7946465dfef20d1a428f969e3443e7386d5f45"
 "checksum quote 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "ea1e0c9bc6bfb0a60d539aab6e338207c1a5456e62f5bd5375132cee119aa4b3"
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index 95778b61c88..cb386d1ac7e 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -14,6 +14,7 @@ doctest = false
 
 [features]
 gecko = ["nsstring_vendor", "num_cpus", "rayon/unstable"]
+bindgen = ["libbindgen", "regex"]
 servo = ["serde/unstable", "serde", "serde_derive", "heapsize_derive",
          "style_traits/servo", "app_units/plugins", "servo_atoms", "html5ever-atoms",
          "cssparser/heap_size", "cssparser/serde-serialization",
@@ -65,5 +66,8 @@ version = "1.0"
 kernel32-sys = "0.2"
 
 [build-dependencies]
+lazy_static = "0.2"
+libbindgen = {version = "0.1.1", optional = true}
 phf_codegen = "0.7.20"
+regex = {version = "0.1", optional = true}
 walkdir = "0.1"
diff --git a/components/style/binding_tools/regen.py b/components/style/binding_tools/regen.py
deleted file mode 100755
index 248d50ea9ea..00000000000
--- a/components/style/binding_tools/regen.py
+++ /dev/null
@@ -1,820 +0,0 @@
-#!/usr/bin/env python
-
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-from __future__ import print_function
-
-import re
-import os
-import sys
-import argparse
-import platform
-import copy
-import subprocess
-import fileinput
-
-import regen_atoms
-
-DESCRIPTION = 'Regenerate the rust version of the structs or the bindings file.'
-TOOLS_DIR = os.path.dirname(os.path.abspath(__file__))
-COMMON_BUILD_KEY = "__common__"
-
-COMPILATION_TARGETS = {
-    # Flags common for all the targets.
-    COMMON_BUILD_KEY: {
-        "flags": [
-            "--no-unstable-rust",
-        ],
-        "clang_flags": [
-            "-x", "c++", "-std=c++14",
-            "-DTRACING=1", "-DIMPL_LIBXUL", "-DMOZ_STYLO_BINDINGS=1",
-            "-DMOZILLA_INTERNAL_API", "-DRUST_BINDGEN", "-DMOZ_STYLO"
-        ],
-        "search_dirs": [
-            "{}/dist/include",
-            "{}/dist/include/nspr",
-            "{}/../nsprpub/pr/include"
-        ],
-        "includes": [
-            "{}/mozilla-config.h",
-        ],
-    },
-    # Generation of style structs.
-    "structs": {
-        "target_dir": "../gecko_bindings",
-        "flags": [
-            "--enable-cxx-namespaces",
-            # FIXME(emilio): Incrementally remove these. Probably mozilla::css
-            # and mozilla::dom are easier.
-            "--raw-line", "pub use self::root::*;",
-            "--raw-line", "pub use self::root::mozilla::*;",
-            "--raw-line", "pub use self::root::mozilla::css::*;",
-            "--raw-line", "pub use self::root::mozilla::dom::*;",
-            "--generate", "types,vars",
-        ],
-        "includes": [
-            "{}/dist/include/gfxFontConstants.h",
-            "{}/dist/include/nsThemeConstants.h",
-            "{}/dist/include/mozilla/dom/AnimationEffectReadOnlyBinding.h",
-            "{}/dist/include/mozilla/ServoElementSnapshot.h",
-            "{}/dist/include/mozilla/dom/Element.h",
-            "{}/dist/include/mozilla/ServoBindings.h",
-        ],
-        "files": [
-            "{}/dist/include/nsStyleStruct.h",
-        ],
-        "build_kinds": {
-            "debug": {
-                "clang_flags": [
-                    "-DDEBUG=1",
-                    "-DJS_DEBUG=1",
-                ]
-            },
-            "release": {
-            }
-        },
-        "raw_lines": [
-            "use atomic_refcell::AtomicRefCell;",
-            "use data::ElementData;",
-        ],
-        "blacklist_types": [
-            "nsString",
-        ],
-        "whitelist_vars": [
-            "NS_THEME_.*",
-            "NODE_.*",
-            "NS_FONT_.*",
-            "NS_STYLE_.*",
-            "NS_CORNER_.*",
-            "NS_RADIUS_.*",
-            "BORDER_COLOR_.*",
-            "BORDER_STYLE_.*"
-        ],
-        "whitelist": [
-            "RawGecko.*",
-            "mozilla::ServoElementSnapshot.*",
-            "mozilla::ConsumeStyleBehavior",
-            "mozilla::LazyComputeBehavior",
-            "mozilla::css::SheetParsingMode",
-            "mozilla::SkipRootBehavior",
-            "mozilla::DisplayItemClip",  # Needed because bindgen generates
-                                         # specialization tests for this even
-                                         # though it shouldn't.
-            ".*ThreadSafe.*Holder",
-            "AnonymousContent",
-            "AudioContext",
-            "CapturingContentInfo",
-            "ConsumeStyleBehavior",
-            "DefaultDelete",
-            "DOMIntersectionObserverEntry",
-            "Element",
-            "FontFamilyList",
-            "FontFamilyListRefCnt",
-            "FontFamilyName",
-            "FontFamilyType",
-            "FragmentOrURL",
-            "FrameRequestCallback",
-            "gfxAlternateValue",
-            "gfxFontFeature",
-            "gfxFontVariation",
-            "GridNamedArea",
-            "Image",
-            "ImageURL",
-            "LazyComputeBehavior",
-            "nsAttrName",
-            "nsAttrValue",
-            "nsBorderColors",
-            "nscolor",
-            "nsChangeHint",
-            "nsCSSKeyword",
-            "nsCSSPropertyID",
-            "nsCSSRect",
-            "nsCSSRect_heap",
-            "nsCSSShadowArray",
-            "nsCSSValue",
-            "nsCSSValueFloatColor",
-            "nsCSSValueGradient",
-            "nsCSSValueGradientStop",
-            "nsCSSValueList",
-            "nsCSSValueList_heap",
-            "nsCSSValuePair_heap",
-            "nsCSSValuePairList",
-            "nsCSSValuePairList_heap",
-            "nsCSSValueTokenStream",
-            "nsCSSValueTriplet_heap",
-            "nsCursorImage",
-            "nsFont",
-            "nsIAtom",
-            "nsMainThreadPtrHandle",
-            "nsMainThreadPtrHolder",
-            "nsMargin",
-            "nsRect",
-            "nsRestyleHint",
-            "nsresult",
-            "nsSize",
-            "nsStyleBackground",
-            "nsStyleBorder",
-            "nsStyleColor",
-            "nsStyleColumn",
-            "nsStyleContent",
-            "nsStyleContentData",
-            "nsStyleContext",
-            "nsStyleCoord",
-            "nsStyleCounterData",
-            "nsStyleDisplay",
-            "nsStyleEffects",
-            "nsStyleFilter",
-            "nsStyleFont",
-            "nsStyleGradient",
-            "nsStyleGradientStop",
-            "nsStyleImage",
-            "nsStyleImageLayers",
-            "nsStyleList",
-            "nsStyleMargin",
-            "nsStyleOutline",
-            "nsStylePadding",
-            "nsStylePosition",
-            "nsStyleSVG",
-            "nsStyleSVGReset",
-            "nsStyleTable",
-            "nsStyleTableBorder",
-            "nsStyleText",
-            "nsStyleTextReset",
-            "nsStyleUIReset",
-            "nsStyleUnion",
-            "nsStyleUnit",
-            "nsStyleUserInterface",
-            "nsStyleVariables",
-            "nsStyleVisibility",
-            "nsStyleXUL",
-            "nsTArray",
-            "nsTArrayHeader",
-            "pair",
-            "Position",
-            "Runnable",
-            "ServoAttrSnapshot",
-            "ServoElementSnapshot",
-            "SheetParsingMode",
-            "Side",
-            "StaticRefPtr",
-            "StyleAnimation",
-            "StyleBasicShape",
-            "StyleBasicShapeType",
-            "StyleClipPath",
-            "StyleClipPathGeometryBox",
-            "StyleTransition",
-            "mozilla::UniquePtr",
-            "mozilla::DefaultDelete",
-        ],
-        "bitfield_enum_types": ["nsChangeHint", "nsRestyleHint"],
-        "opaque_types": [
-            "atomic___base",
-            "nsAString_internal_char_traits",
-            "nsAString_internal_incompatible_char_type",
-            "nsACString_internal_char_traits",
-            "nsACString_internal_incompatible_char_type",
-            "RefPtr_Proxy",
-            "RefPtr_Proxy_member_function",
-            "nsAutoPtr_Proxy",
-            "nsAutoPtr_Proxy_member_function",
-            "mozilla::detail::PointerType",
-            "mozilla::Pair_Base",
-            "mozilla::SupportsWeakPtr",
-            "SupportsWeakPtr",
-            "mozilla::detail::WeakReference",
-            "mozilla::WeakPtr",
-            "nsWritingIterator_reference", "nsReadingIterator_reference",
-            "nsTObserverArray",  # <- Inherits from nsAutoTObserverArray<T, 0>
-            "nsTHashtable",  # <- Inheriting from inner typedefs that clang
-                             #    doesn't expose properly.
-            "nsRefPtrHashtable", "nsDataHashtable", "nsClassHashtable",  # <- Ditto
-            "nsIDocument_SelectorCache",  # <- Inherits from nsExpirationTracker<.., 4>
-            "nsIPresShell_ScrollAxis",  # <- For some reason the alignment of this is 4
-                                        # for clang.
-            "nsPIDOMWindow",  # <- Takes the vtable from a template parameter, and we can't
-                              #    generate it conditionally.
-            "JS::Rooted",
-            "mozilla::Maybe",
-            "gfxSize",  # <- union { struct { T width; T height; }; T components[2] };
-            "gfxSize_Super",  # Ditto.
-            "mozilla::ErrorResult",  # Causes JSWhyMagic to be included & handled incorrectly.
-        ],
-        "manual_fixups": [
-            ["root::nsString", "::nsstring::nsStringRepr"]
-        ],
-        "servo_mapped_generic_types": [
-            {
-                "generic": True,
-                "gecko": "mozilla::ServoUnsafeCell",
-                "servo": "::std::cell::UnsafeCell"
-            }, {
-                "generic": True,
-                "gecko": "mozilla::ServoCell",
-                "servo": "::std::cell::Cell"
-            }, {
-                "generic": False,
-                "gecko": "ServoNodeData",
-                "servo": "AtomicRefCell<ElementData>",
-            }
-        ],
-    },
-    # Generation of the ffi bindings.
-    "bindings": {
-        "target_dir": "../gecko_bindings",
-        "raw_lines": [
-            "pub use nsstring::{nsACString, nsAString};",
-            "type nsACString_internal = nsACString;",
-            "type nsAString_internal = nsAString;"
-        ],
-        "flags": [
-            "--generate", "functions",
-            "--disable-name-namespacing",
-        ],
-        "match_headers": [
-            "ServoBindingList.h",
-            "ServoBindings.h",
-            "ServoTypes.h",
-            "nsStyleStructList.h",
-        ],
-        "files": [
-            "{}/dist/include/mozilla/ServoBindings.h",
-        ],
-        # Types to just use from the `structs` target.
-        "structs_types": [
-            "RawGeckoDocument",
-            "RawGeckoElement",
-            "RawGeckoNode",
-            "ThreadSafeURIHolder",
-            "ThreadSafePrincipalHolder",
-            "ConsumeStyleBehavior",
-            "LazyComputeBehavior",
-            "SkipRootBehavior",
-            "FontFamilyList",
-            "FontFamilyType",
-            "ServoElementSnapshot",
-            "SheetParsingMode",
-            "StyleBasicShape",
-            "StyleBasicShapeType",
-            "StyleClipPath",
-            "nsCSSKeyword",
-            "nsCSSShadowArray",
-            "nsCSSValue",
-            "nsCSSValueSharedList",
-            "nsChangeHint",
-            "nsCursorImage",
-            "nsFont",
-            "nsIAtom",
-            "nsRestyleHint",
-            "nsStyleBackground",
-            "nsStyleBorder",
-            "nsStyleColor",
-            "nsStyleColumn",
-            "nsStyleContent",
-            "nsStyleContext",
-            "nsStyleCoord",
-            "nsStyleCoord_Calc",
-            "nsStyleCoord_CalcValue",
-            "nsStyleDisplay",
-            "nsStyleEffects",
-            "nsStyleFont",
-            "nsStyleGradient",
-            "nsStyleGradientStop",
-            "nsStyleImage",
-            "nsStyleImageLayers",
-            "nsStyleImageLayers_Layer",
-            "nsStyleImageLayers_LayerType",
-            "nsStyleImageRequest",
-            "nsStyleList",
-            "nsStyleMargin",
-            "nsStyleOutline",
-            "nsStylePadding",
-            "nsStylePosition",
-            "nsStyleQuoteValues",
-            "nsStyleSVG",
-            "nsStyleSVGReset",
-            "nsStyleTable",
-            "nsStyleTableBorder",
-            "nsStyleText",
-            "nsStyleTextReset",
-            "nsStyleUIReset",
-            "nsStyleUnion",
-            "nsStyleUnit",
-            "nsStyleUserInterface",
-            "nsStyleVariables",
-            "nsStyleVisibility",
-            "nsStyleXUL",
-            "nscoord",
-            "nsresult",
-        ],
-        "array_types": {
-            "uintptr_t": "usize",
-        },
-        "servo_nullable_arc_types": [
-            "ServoComputedValues",
-            "ServoCssRules",
-            "RawServoStyleSheet",
-            "RawServoDeclarationBlock",
-            "RawServoStyleRule",
-        ],
-        "servo_owned_types": [
-            {
-                "name": "RawServoStyleSet",
-                "opaque": True,
-            }, {
-                "name": "StyleChildrenIterator",
-                "opaque": True,
-            }, {
-                "name": "ServoElementSnapshot",
-                "opaque": False,
-            },
-        ],
-        "servo_immutable_borrow_types": [
-            "RawGeckoNode",
-            "RawGeckoElement",
-            "RawGeckoDocument",
-            "RawServoDeclarationBlockStrong",
-        ],
-        "servo_borrow_types": [
-            "nsCSSValue",
-        ],
-        "whitelist_functions": [
-            "Servo_.*",
-            "Gecko_.*"
-        ]
-    },
-
-    "atoms": {
-        "custom_build": regen_atoms.build,
-    }
-}
-
-
-def platform_dependent_defines():
-    ret = []
-
-    if os.name == "posix":
-        ret.append("-DOS_POSIX=1")
-
-    system = platform.system()
-    if system == "Linux":
-        ret.append("-DOS_LINUX=1")
-    elif system == "Darwin":
-        ret.append("-DOS_MACOSX=1")
-    elif system == "Windows":
-        ret.append("-DOS_WIN=1")
-        ret.append("-DWIN32=1")
-        msvc_platform = os.environ["PLATFORM"]
-        if msvc_platform == "X86":
-            ret.append("--target=i686-pc-win32")
-        elif msvc_platform == "X64":
-            ret.append("--target=x86_64-pc-win32")
-        else:
-            raise Exception("Only MSVC builds are supported on Windows")
-        # For compatibility with MSVC 2015
-        ret.append("-fms-compatibility-version=19")
-        # To enable the builtin __builtin_offsetof so that CRT wouldn't
-        # use reinterpret_cast in offsetof() which is not allowed inside
-        # static_assert().
-        ret.append("-D_CRT_USE_BUILTIN_OFFSETOF")
-        # Enable hidden attribute (which is not supported by MSVC and
-        # thus not enabled by default with a MSVC-compatibile build)
-        # to exclude hidden symbols from the generated file.
-        ret.append("-DHAVE_VISIBILITY_HIDDEN_ATTRIBUTE=1")
-    else:
-        raise Exception("Unknown platform")
-
-    return ret
-
-
-def extend_object(obj, other):
-    if not obj or not other:
-        return obj
-
-    if isinstance(obj, list) and isinstance(other, list):
-        obj.extend(other)
-        return
-
-    assert isinstance(obj, dict) and isinstance(other, dict)
-
-    for key in other.keys():
-        if key in obj:
-            extend_object(obj[key], other[key])
-        else:
-            obj[key] = copy.deepcopy(other[key])
-
-
-def build(objdir, target_name, debug, debugger, kind_name=None,
-          output_filename=None, bindgen=None, skip_test=False,
-          verbose=False):
-    assert target_name in COMPILATION_TARGETS
-
-    current_target = COMPILATION_TARGETS[target_name]
-    if COMMON_BUILD_KEY in COMPILATION_TARGETS:
-        current_target = copy.deepcopy(COMPILATION_TARGETS[COMMON_BUILD_KEY])
-        extend_object(current_target, COMPILATION_TARGETS[target_name])
-
-    assert ((kind_name is None and "build_kinds" not in current_target) or
-            (kind_name in current_target["build_kinds"]))
-
-    if "custom_build" in current_target:
-        print("[CUSTOM] {}::{} in \"{}\"... ".format(target_name, kind_name, objdir), end='')
-        sys.stdout.flush()
-        ret = current_target["custom_build"](objdir, verbose=True)
-        if ret != 0:
-            print("FAIL")
-        else:
-            print("OK")
-
-        return ret
-
-    if bindgen is None:
-        bindgen = os.path.join(TOOLS_DIR, "rust-bindgen")
-
-    if os.path.isdir(bindgen):
-        bindgen = ["cargo", "run", "--manifest-path",
-                   os.path.join(bindgen, "Cargo.toml"), "--features", "llvm_stable", "--release", "--"]
-    else:
-        bindgen = [bindgen]
-
-    if kind_name is not None:
-        current_target = copy.deepcopy(current_target)
-        extend_object(current_target, current_target["build_kinds"][kind_name])
-
-    target_dir = None
-    if output_filename is None and "target_dir" in current_target:
-        target_dir = current_target["target_dir"]
-
-    if output_filename is None:
-        output_filename = "{}.rs".format(target_name)
-
-        if kind_name is not None:
-            output_filename = "{}_{}.rs".format(target_name, kind_name)
-
-    if target_dir:
-        output_filename = "{}/{}".format(target_dir, output_filename)
-
-    print("[BINDGEN] {}::{} in \"{}\"... ".format(target_name, kind_name, objdir), end='')
-    sys.stdout.flush()
-
-    flags = []
-
-    # Types we have to fixup since we insert them manually.
-    #
-    # Bindgen only allows us to add stuff outside of the root module. This
-    # wasn't intended to add new types, but we do so, so we postprocess the
-    # bindgen output to fixup the path to these types.
-    fixups = []
-
-    if "manual_fixups" in current_target:
-        fixups = current_target["manual_fixups"]
-
-    # This makes an FFI-safe void type that can't be matched on
-    # &VoidType is UB to have, because you can match on it
-    # to produce a reachable unreachable. If it's wrapped in
-    # a struct as a private field it becomes okay again
-    #
-    # Not 100% sure of how safe this is, but it's what we're using
-    # in the XPCOM ffi too
-    # https://github.com/nikomatsakis/rust-memory-model/issues/2
-    def zero_size_type(ty, flags):
-        flags.append("--blacklist-type")
-        flags.append(ty)
-        flags.append("--raw-line")
-        flags.append("enum {0}Void{{ }}".format(ty))
-        flags.append("--raw-line")
-        flags.append("pub struct {0}({0}Void);".format(ty))
-
-    if "flags" in current_target:
-        flags.extend(current_target["flags"])
-
-    clang_flags = []
-
-    if "clang_flags" in current_target:
-        clang_flags.extend(current_target["clang_flags"])
-
-    clang_flags.extend(platform_dependent_defines())
-
-    if platform.system() == "Windows":
-        flags.append("--use-msvc-mangling")
-
-    if "raw_lines" in current_target:
-        for raw_line in current_target["raw_lines"]:
-            flags.append("--raw-line")
-            flags.append(raw_line)
-
-    if "search_dirs" in current_target:
-        for dir_name in current_target["search_dirs"]:
-            clang_flags.append("-I")
-            clang_flags.append(dir_name.format(objdir))
-
-    if "includes" in current_target:
-        for file_name in current_target["includes"]:
-            clang_flags.append("-include")
-            clang_flags.append(file_name.format(objdir))
-
-    if "whitelist" in current_target:
-        for header in current_target["whitelist"]:
-            flags.append("--whitelist-type")
-            flags.append(header)
-
-    if "whitelist_functions" in current_target:
-        for header in current_target["whitelist_functions"]:
-            flags.append("--whitelist-function")
-            flags.append(header)
-
-    if "whitelist_vars" in current_target:
-        for header in current_target["whitelist_vars"]:
-            flags.append("--whitelist-var")
-            flags.append(header)
-
-    if "bitfield_enum_types" in current_target:
-        for ty in current_target["bitfield_enum_types"]:
-            flags.append("--bitfield-enum")
-            flags.append(ty)
-
-    if "opaque_types" in current_target:
-        for ty in current_target["opaque_types"]:
-            flags.append("--opaque-type")
-            flags.append(ty)
-
-    if "array_types" in current_target:
-        for cpp_type, rust_type in current_target["array_types"].items():
-            flags.append("--blacklist-type")
-            flags.append("nsTArrayBorrowed_{}".format(cpp_type))
-            flags.append("--raw-line")
-            flags.append("pub type nsTArrayBorrowed_{0}<'a> = &'a mut ::gecko_bindings::structs::nsTArray<{1}>;"
-                         .format(cpp_type, rust_type))
-
-    if "blacklist_types" in current_target:
-        for ty in current_target["blacklist_types"]:
-            flags.append("--blacklist-type")
-            flags.append(ty)
-
-    if "servo_nullable_arc_types" in current_target:
-        for ty in current_target["servo_nullable_arc_types"]:
-            flags.append("--blacklist-type")
-            flags.append("{}Strong".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}Strong = ::gecko_bindings::sugar::ownership::Strong<{0}>;"
-                         .format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedOrNull".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedOrNull<'a> = \
-Option<&'a {0}>;".format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}Borrowed".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}Borrowed<'a> = &'a {0};".format(ty))
-            zero_size_type(ty, flags)
-
-    if "servo_immutable_borrow_types" in current_target:
-        for ty in current_target.get("servo_immutable_borrow_types", []) + current_target.get("servo_borrow_types", []):
-            flags.append("--blacklist-type")
-            flags.append("{}Borrowed".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}Borrowed<'a> = &'a {0};".format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedOrNull".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedOrNull<'a> = Option<&'a {0}>;".format(ty))
-    if "servo_borrow_types" in current_target:
-        for ty in current_target["servo_borrow_types"]:
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedMut".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedMut<'a> = &'a mut {0};".format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedMutOrNull".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedMutOrNull<'a> = \
-Option<&'a mut {0}>;".format(ty))
-            # Right now the only immutable borrow types are ones which we import
-            # from the |structs| module. As such, we don't need to create an opaque
-            # type with zero_size_type. If we ever introduce immutable borrow types
-            # which _do_ need to be opaque, we'll need a separate mode.
-
-    if "servo_mapped_generic_types" in current_target:
-        for ty in current_target["servo_mapped_generic_types"]:
-            flags.append("--blacklist-type")
-            flags.append(ty["gecko"])
-
-            gecko_name = ty["gecko"].split("::")[-1]
-            flags.append("--raw-line")
-            flags.append("pub type {0}{2} = {1}{2};".format(gecko_name, ty["servo"], "<T>" if ty["generic"] else ""))
-            fixups.append(["root::{}".format(ty["gecko"]), "::gecko_bindings::structs::{}".format(gecko_name)])
-
-    if "servo_owned_types" in current_target:
-        for entry in current_target["servo_owned_types"]:
-            ty = entry["name"]
-            flags.append("--blacklist-type")
-            flags.append("{}Borrowed".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}Borrowed<'a> = &'a {0};".format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedMut".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedMut<'a> = &'a mut {0};".format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}Owned".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}Owned = ::gecko_bindings::sugar::ownership::Owned<{0}>;".format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedOrNull".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedOrNull<'a> = Option<&'a {0}>;"
-                         .format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}BorrowedMutOrNull".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}BorrowedMutOrNull<'a> = Option<&'a mut {0}>;"
-                         .format(ty))
-            flags.append("--blacklist-type")
-            flags.append("{}OwnedOrNull".format(ty))
-            flags.append("--raw-line")
-            flags.append("pub type {0}OwnedOrNull = ::gecko_bindings::sugar::ownership::OwnedOrNull<{0}>;".format(ty))
-            if entry["opaque"]:
-                zero_size_type(ty, flags)
-
-    if "structs_types" in current_target:
-        for ty in current_target["structs_types"]:
-            flags.append("--blacklist-type")
-            flags.append(ty)
-            flags.append("--raw-line")
-            flags.append("use gecko_bindings::structs::{};".format(ty))
-
-            # TODO: this is hacky, figure out a better way to do it without
-            # hardcoding everything...
-            if ty.startswith("nsStyle"):
-                flags.extend([
-                    "--raw-line",
-                    "unsafe impl Send for {} {{}}".format(ty),
-                    "--raw-line",
-                    "unsafe impl Sync for {} {{}}".format(ty),
-                ])
-
-    flags.append("-o")
-    flags.append(output_filename)
-
-    assert len(current_target["files"]) == 1
-    flags.append(current_target["files"][0].format(objdir))
-
-    flags = bindgen + flags + ["--"] + clang_flags
-
-    if verbose:
-        print(flags)
-
-    output = ""
-    try:
-        if debug:
-            flags = [debugger, "--args"] + flags
-            subprocess.check_call(flags)
-        else:
-            output = subprocess.check_output(flags, stderr=subprocess.STDOUT,
-                                             universal_newlines=True)
-    except subprocess.CalledProcessError as e:
-        print("FAIL\n", e.output)
-        return 1
-
-    generated = fileinput.input(output_filename, inplace=True)
-    for line in generated:
-        for fixup in fixups:
-            line = re.sub("\\b{}\\b".format(fixup[0]), fixup[1], line)
-        print(line, end='')
-    generated.close()
-
-    print("OK")
-    print("(please test with ./mach test-stylo)")
-
-    if verbose:
-        print(output)
-
-    return 0
-
-
-def builds_for(target_name, kind):
-    if target_name == "all":
-        for target in COMPILATION_TARGETS.keys():
-            if target == COMMON_BUILD_KEY:
-                continue
-
-            if "build_kinds" in COMPILATION_TARGETS[target]:
-                for kind in COMPILATION_TARGETS[target]["build_kinds"].keys():
-                    yield (target, kind)
-            else:
-                yield (target, None)
-        return
-
-    target = COMPILATION_TARGETS[target_name]
-    if "build_kinds" in target:
-        if kind is None:
-            for kind in target["build_kinds"].keys():
-                yield(target_name, kind)
-        else:
-            yield (target_name, kind)
-        return
-
-    yield (target_name, None)
-
-
-def main():
-    parser = argparse.ArgumentParser(description=DESCRIPTION)
-    parser.add_argument('--target', default='all',
-                        help='The target to build, either "structs" or "bindings"')
-    parser.add_argument('--kind',
-                        help='Kind of build')
-    parser.add_argument('--bindgen',
-                        help='Override bindgen binary')
-    parser.add_argument('--output', '-o',
-                        help='Output of the script')
-    parser.add_argument('--skip-test',
-                        action='store_true',
-                        help='Skip automatic tests, useful for debugging')
-    parser.add_argument('--verbose', '-v',
-                        action='store_true',
-                        help='Be... verbose')
-    parser.add_argument('--debug',
-                        action='store_true',
-                        help='Try to use a debugger to debug bindgen commands (default: gdb)')
-    parser.add_argument('--debugger', default='gdb',
-                        help='Debugger to use. Only used if --debug is passed.')
-    parser.add_argument('objdir')
-
-    args = parser.parse_args()
-
-    if not os.path.isdir(args.objdir):
-        print("\"{}\" doesn't seem to be a directory".format(args.objdir))
-        return 1
-
-    if (args.target != "all" and args.target not in COMPILATION_TARGETS) or args.target == COMMON_BUILD_KEY:
-        print("{} is not a valid compilation target.".format(args.target))
-        print("Valid compilation targets are:")
-        for target in COMPILATION_TARGETS.keys():
-            if target != COMMON_BUILD_KEY:
-                print("\t * {}".format(target))
-        return 1
-
-    current_target = COMPILATION_TARGETS.get(args.target, {})
-    if args.kind and "build_kinds" in current_target and args.kind not in current_target["build_kinds"]:
-        print("{} is not a valid build kind.".format(args.kind))
-        print("Valid build kinds are:")
-        for kind in current_target["build_kinds"].keys():
-            print("\t * {}".format(kind))
-        return 1
-
-    for target, kind in builds_for(args.target, args.kind):
-        ret = build(args.objdir, target, kind_name=kind,
-                    debug=args.debug, debugger=args.debugger,
-                    bindgen=args.bindgen, skip_test=args.skip_test,
-                    output_filename=args.output,
-                    verbose=args.verbose)
-        if ret != 0:
-            print("{}::{} failed".format(target, kind))
-            return ret
-
-    return 0
-
-if __name__ == '__main__':
-    sys.exit(main())
diff --git a/components/style/build.rs b/components/style/build.rs
index 8d68fe45ce6..fb8d4a5e5f9 100644
--- a/components/style/build.rs
+++ b/components/style/build.rs
@@ -2,6 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#[macro_use]
+extern crate lazy_static;
+#[cfg(feature = "bindgen")]
+extern crate libbindgen;
+#[cfg(feature = "bindgen")]
+extern crate regex;
 extern crate walkdir;
 extern crate phf_codegen;
 
@@ -12,6 +18,14 @@ use std::path::Path;
 use std::process::{Command, exit};
 use walkdir::WalkDir;
 
+#[cfg(feature = "gecko")]
+mod build_gecko;
+
+#[cfg(not(feature = "gecko"))]
+mod build_gecko {
+    pub fn generate() {}
+}
+
 #[cfg(windows)]
 fn find_python() -> String {
     if Command::new("python2.7.exe").arg("--version").output().is_ok() {
@@ -39,8 +53,7 @@ fn find_python() -> String {
     }.to_owned()
 }
 
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
+fn generate_properties() {
     for entry in WalkDir::new("properties") {
         let entry = entry.unwrap();
         match entry.path().extension().and_then(|e| e.to_str()) {
@@ -82,3 +95,9 @@ fn main() {
     map.build(&mut file).unwrap();
     write!(&mut file, ";\n").unwrap();
 }
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+    generate_properties();
+    build_gecko::generate();
+}
diff --git a/components/style/build_gecko.rs b/components/style/build_gecko.rs
new file mode 100644
index 00000000000..a96a92e9871
--- /dev/null
+++ b/components/style/build_gecko.rs
@@ -0,0 +1,617 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+mod common {
+    use std::env;
+    use std::path::PathBuf;
+
+    lazy_static! {
+        pub static ref OUTDIR_PATH: PathBuf = PathBuf::from(env::var("OUT_DIR").unwrap()).join("gecko");
+    }
+
+    pub const STRUCTS_DEBUG_FILE: &'static str = "structs_debug.rs";
+    pub const STRUCTS_RELEASE_FILE: &'static str = "structs_release.rs";
+    pub const BINDINGS_FILE: &'static str = "bindings.rs";
+
+    #[derive(Clone, Copy, PartialEq)]
+    pub enum BuildType {
+        Debug,
+        Release,
+    }
+
+    pub fn structs_file(build_type: BuildType) -> &'static str {
+        match build_type {
+            BuildType::Debug => STRUCTS_DEBUG_FILE,
+            BuildType::Release => STRUCTS_RELEASE_FILE
+        }
+    }
+}
+
+#[cfg(feature = "bindgen")]
+mod bindings {
+    use libbindgen::{Builder, CodegenConfig};
+    use regex::Regex;
+    use std::collections::HashSet;
+    use std::env;
+    use std::fs::File;
+    use std::io::{BufWriter, Read, Write};
+    use std::path::PathBuf;
+    use std::sync::Mutex;
+    use super::common::*;
+
+    lazy_static! {
+        static ref INCLUDE_RE: Regex = Regex::new(r#"#include\s*"(.+?)""#).unwrap();
+        static ref DISTDIR_PATH: PathBuf = PathBuf::from(env::var("MOZ_DIST").unwrap());
+        static ref SEARCH_PATHS: Vec<PathBuf> = vec![
+            DISTDIR_PATH.join("include"),
+            DISTDIR_PATH.join("include/nspr"),
+        ];
+        static ref ADDED_PATHS: Mutex<HashSet<PathBuf>> = Mutex::new(HashSet::new());
+    }
+
+    fn search_include(name: &str) -> Option<PathBuf> {
+        for path in SEARCH_PATHS.iter() {
+            let file = path.join(name);
+            if file.is_file() {
+                return Some(file);
+            }
+        }
+        None
+    }
+
+    fn add_headers_recursively(path: PathBuf, added_paths: &mut HashSet<PathBuf>) {
+        if added_paths.contains(&path) {
+            return;
+        }
+        let mut file = File::open(&path).unwrap();
+        let mut content = String::new();
+        file.read_to_string(&mut content).unwrap();
+        println!("cargo:rerun-if-changed={}", path.to_str().unwrap());
+        added_paths.insert(path);
+        // Find all includes and add them recursively
+        for cap in INCLUDE_RE.captures_iter(&content) {
+            if let Some(path) = search_include(cap.at(1).unwrap()) {
+                add_headers_recursively(path, added_paths);
+            }
+        }
+    }
+
+    fn add_include(name: &str) -> String {
+        let mut added_paths = ADDED_PATHS.lock().unwrap();
+        let file = search_include(name).unwrap();
+        let result = String::from(file.to_str().unwrap());
+        add_headers_recursively(file, &mut *added_paths);
+        result
+    }
+
+    trait BuilderExt {
+        fn get_initial_builder(build_type: BuildType) -> Builder;
+        fn include<T: Into<String>>(self, file: T) -> Builder;
+        fn zero_size_type(self, ty: &str) -> Builder;
+        fn borrowed_type(self, ty: &str) -> Builder;
+        fn mutable_borrowed_type(self, ty: &str) -> Builder;
+    }
+
+    impl BuilderExt for Builder {
+        fn get_initial_builder(build_type: BuildType) -> Builder {
+            let mut builder = Builder::default().no_unstable_rust();
+            let args = [
+                "-x", "c++", "-std=c++14",
+                "-DTRACING=1", "-DIMPL_LIBXUL", "-DMOZ_STYLO_BINDINGS=1",
+                "-DMOZILLA_INTERNAL_API", "-DRUST_BINDGEN", "-DMOZ_STYLO"
+            ];
+            for &arg in args.iter() {
+                builder = builder.clang_arg(arg);
+            }
+            for dir in SEARCH_PATHS.iter() {
+                builder = builder.clang_arg("-I").clang_arg(dir.to_str().unwrap());
+            }
+            builder = builder.include(add_include("mozilla-config.h"));
+
+            if build_type == BuildType::Debug {
+                builder = builder.clang_arg("-DDEBUG=1").clang_arg("-DJS_DEBUG=1");
+            }
+            if cfg!(target_family = "unix") {
+                builder = builder.clang_arg("-DOS_POSIX=1");
+            }
+            if cfg!(target_os = "linux") {
+                builder = builder.clang_arg("-DOS_LINUX=1");
+            } else if cfg!(target_os = "macos") {
+                builder = builder.clang_arg("-DOS_MACOSX=1");
+            } else if cfg!(target_env = "msvc") {
+                builder = builder.clang_arg("-DOS_WIN=1").clang_arg("-DWIN32=1")
+                    // For compatibility with MSVC 2015
+                    .clang_arg("-fms-compatibility-version=19")
+                    // To enable the builtin __builtin_offsetof so that CRT wouldn't
+                    // use reinterpret_cast in offsetof() which is not allowed inside
+                    // static_assert().
+                    .clang_arg("-D_CRT_USE_BUILTIN_OFFSETOF")
+                    // Enable hidden attribute (which is not supported by MSVC and
+                    // thus not enabled by default with a MSVC-compatibile build)
+                    // to exclude hidden symbols from the generated file.
+                    .clang_arg("-DHAVE_VISIBILITY_HIDDEN_ATTRIBUTE=1");
+                if cfg!(target_pointer_width = "32") {
+                    builder = builder.clang_arg("--target=i686-pc-win32");
+                } else {
+                    builder = builder.clang_arg("--target=x86_64-pc-win32");
+                }
+            } else {
+                panic!("Unknown platform");
+            }
+            builder
+        }
+        fn include<T: Into<String>>(self, file: T) -> Builder {
+            self.clang_arg("-include").clang_arg(file)
+        }
+        // This makes an FFI-safe void type that can't be matched on
+        // &VoidType is UB to have, because you can match on it
+        // to produce a reachable unreachable. If it's wrapped in
+        // a struct as a private field it becomes okay again
+        //
+        // Not 100% sure of how safe this is, but it's what we're using
+        // in the XPCOM ffi too
+        // https://github.com/nikomatsakis/rust-memory-model/issues/2
+        fn zero_size_type(self, ty: &str) -> Builder {
+            self.hide_type(ty)
+                .raw_line(format!("enum {}Void {{ }}", ty))
+                .raw_line(format!("pub struct {0}({0}Void);", ty))
+        }
+        fn borrowed_type(self, ty: &str) -> Builder {
+            self.hide_type(format!("{}Borrowed", ty))
+                .raw_line(format!("pub type {0}Borrowed<'a> = &'a {0};", ty))
+                .hide_type(format!("{}BorrowedOrNull", ty))
+                .raw_line(format!("pub type {0}BorrowedOrNull<'a> = Option<&'a {0}>;", ty))
+        }
+        fn mutable_borrowed_type(self, ty: &str) -> Builder {
+            self.borrowed_type(ty)
+                .hide_type(format!("{}BorrowedMut", ty))
+                .raw_line(format!("pub type {0}BorrowedMut<'a> = &'a mut {0};", ty))
+                .hide_type(format!("{}BorrowedMutOrNull", ty))
+                .raw_line(format!("pub type {0}BorrowedMutOrNull<'a> = Option<&'a mut {0}>;", ty))
+        }
+    }
+
+    fn write_binding_file(builder: Builder, file: &str) {
+        let bindings = builder.generate().expect("Unable to generate bindings");
+        let binding_file = File::create(&OUTDIR_PATH.join(file)).unwrap();
+        bindings.write(Box::new(BufWriter::new(binding_file))).expect("Unable to write output");
+    }
+
+    pub fn generate_structs(build_type: BuildType) {
+        let mut builder = Builder::get_initial_builder(build_type)
+            .enable_cxx_namespaces()
+            .with_codegen_config(CodegenConfig {
+                types: true,
+                vars: true,
+                ..CodegenConfig::nothing()
+            })
+            .header(add_include("nsStyleStruct.h"))
+            .include(add_include("gfxFontConstants.h"))
+            .include(add_include("nsThemeConstants.h"))
+            .include(add_include("mozilla/dom/AnimationEffectReadOnlyBinding.h"))
+            .include(add_include("mozilla/ServoElementSnapshot.h"))
+            .include(add_include("mozilla/dom/Element.h"))
+            .include(add_include("mozilla/ServoBindings.h"))
+            // FIXME(emilio): Incrementally remove these "pub use"s. Probably
+            // mozilla::css and mozilla::dom are easier.
+            .raw_line("pub use self::root::*;")
+            .raw_line("pub use self::root::mozilla::*;")
+            .raw_line("pub use self::root::mozilla::css::*;")
+            .raw_line("pub use self::root::mozilla::dom::*;")
+            .raw_line("use atomic_refcell::AtomicRefCell;")
+            .raw_line("use data::ElementData;")
+            .hide_type("nsString")
+            .bitfield_enum("nsChangeHint")
+            .bitfield_enum("nsRestyleHint");
+        let whitelist_vars = [
+            "NS_THEME_.*",
+            "NODE_.*",
+            "NS_FONT_.*",
+            "NS_STYLE_.*",
+            "NS_CORNER_.*",
+            "NS_RADIUS_.*",
+            "BORDER_COLOR_.*",
+            "BORDER_STYLE_.*"
+        ];
+        let whitelist = [
+            "RawGecko.*",
+            "mozilla::ServoElementSnapshot.*",
+            "mozilla::ConsumeStyleBehavior",
+            "mozilla::LazyComputeBehavior",
+            "mozilla::css::SheetParsingMode",
+            "mozilla::SkipRootBehavior",
+            "mozilla::DisplayItemClip",  // Needed because bindgen generates
+                                         // specialization tests for this even
+                                         // though it shouldn't.
+            ".*ThreadSafe.*Holder",
+            "AnonymousContent",
+            "AudioContext",
+            "CapturingContentInfo",
+            "ConsumeStyleBehavior",
+            "DefaultDelete",
+            "DOMIntersectionObserverEntry",
+            "Element",
+            "FontFamilyList",
+            "FontFamilyListRefCnt",
+            "FontFamilyName",
+            "FontFamilyType",
+            "FragmentOrURL",
+            "FrameRequestCallback",
+            "gfxAlternateValue",
+            "gfxFontFeature",
+            "gfxFontVariation",
+            "GridNamedArea",
+            "Image",
+            "ImageURL",
+            "LazyComputeBehavior",
+            "nsAttrName",
+            "nsAttrValue",
+            "nsBorderColors",
+            "nscolor",
+            "nsChangeHint",
+            "nsCSSKeyword",
+            "nsCSSPropertyID",
+            "nsCSSRect",
+            "nsCSSRect_heap",
+            "nsCSSShadowArray",
+            "nsCSSValue",
+            "nsCSSValueFloatColor",
+            "nsCSSValueGradient",
+            "nsCSSValueGradientStop",
+            "nsCSSValueList",
+            "nsCSSValueList_heap",
+            "nsCSSValuePair_heap",
+            "nsCSSValuePairList",
+            "nsCSSValuePairList_heap",
+            "nsCSSValueTokenStream",
+            "nsCSSValueTriplet_heap",
+            "nsCursorImage",
+            "nsFont",
+            "nsIAtom",
+            "nsMainThreadPtrHandle",
+            "nsMainThreadPtrHolder",
+            "nsMargin",
+            "nsRect",
+            "nsRestyleHint",
+            "nsresult",
+            "nsSize",
+            "nsStyleBackground",
+            "nsStyleBorder",
+            "nsStyleColor",
+            "nsStyleColumn",
+            "nsStyleContent",
+            "nsStyleContentData",
+            "nsStyleContext",
+            "nsStyleCoord",
+            "nsStyleCounterData",
+            "nsStyleDisplay",
+            "nsStyleEffects",
+            "nsStyleFilter",
+            "nsStyleFont",
+            "nsStyleGradient",
+            "nsStyleGradientStop",
+            "nsStyleImage",
+            "nsStyleImageLayers",
+            "nsStyleList",
+            "nsStyleMargin",
+            "nsStyleOutline",
+            "nsStylePadding",
+            "nsStylePosition",
+            "nsStyleSVG",
+            "nsStyleSVGReset",
+            "nsStyleTable",
+            "nsStyleTableBorder",
+            "nsStyleText",
+            "nsStyleTextReset",
+            "nsStyleUIReset",
+            "nsStyleUnion",
+            "nsStyleUnit",
+            "nsStyleUserInterface",
+            "nsStyleVariables",
+            "nsStyleVisibility",
+            "nsStyleXUL",
+            "nsTArray",
+            "nsTArrayHeader",
+            "pair",
+            "Position",
+            "Runnable",
+            "ServoAttrSnapshot",
+            "ServoElementSnapshot",
+            "SheetParsingMode",
+            "mozilla::Side",
+            "StaticRefPtr",
+            "StyleAnimation",
+            "StyleBasicShape",
+            "StyleBasicShapeType",
+            "StyleClipPath",
+            "StyleClipPathGeometryBox",
+            "StyleTransition",
+            "mozilla::UniquePtr",
+            "mozilla::DefaultDelete",
+        ];
+        let opaque_types = [
+            "atomic___base", "std::atomic__My_base",
+            "nsAString_internal_char_traits",
+            "nsAString_internal_incompatible_char_type",
+            "nsACString_internal_char_traits",
+            "nsACString_internal_incompatible_char_type",
+            "RefPtr_Proxy",
+            "RefPtr_Proxy_member_function",
+            "nsAutoPtr_Proxy",
+            "nsAutoPtr_Proxy_member_function",
+            "mozilla::detail::PointerType",
+            "mozilla::Pair_Base",
+            "mozilla::SupportsWeakPtr",
+            "SupportsWeakPtr",
+            "mozilla::detail::WeakReference",
+            "mozilla::WeakPtr",
+            "nsWritingIterator_reference", "nsReadingIterator_reference",
+            "nsTObserverArray",  // <- Inherits from nsAutoTObserverArray<T, 0>
+            "nsTHashtable",  // <- Inheriting from inner typedefs that clang
+                             //    doesn't expose properly.
+            "nsRefPtrHashtable", "nsDataHashtable", "nsClassHashtable",  // <- Ditto
+            "nsIDocument_SelectorCache",  // <- Inherits from nsExpirationTracker<.., 4>
+            "nsIPresShell_ScrollAxis",  // <- For some reason the alignment of this is 4
+                                        // for clang.
+            "nsPIDOMWindow",  // <- Takes the vtable from a template parameter, and we can't
+                              //    generate it conditionally.
+            "JS::Rooted",
+            "mozilla::Maybe",
+            "gfxSize",  // <- union { struct { T width; T height; }; T components[2] };
+            "gfxSize_Super",  // Ditto.
+            "mozilla::ErrorResult",  // Causes JSWhyMagic to be included & handled incorrectly.
+        ];
+        struct MappedGenericType {
+            generic: bool,
+            gecko: &'static str,
+            servo: &'static str,
+        }
+        let servo_mapped_generic_types = [
+            MappedGenericType {
+                generic: true,
+                gecko: "mozilla::ServoUnsafeCell",
+                servo: "::std::cell::UnsafeCell"
+            },
+            MappedGenericType {
+                generic: true,
+                gecko: "mozilla::ServoCell",
+                servo: "::std::cell::Cell"
+            },
+            MappedGenericType {
+                generic: false,
+                gecko: "ServoNodeData",
+                servo: "AtomicRefCell<ElementData>",
+            }
+        ];
+        struct Fixup {
+            pat: String,
+            rep: String
+        }
+        let mut fixups = vec![
+            Fixup {
+                pat: "root::nsString".into(),
+                rep: "::nsstring::nsStringRepr".into()
+            },
+        ];
+        for &var in whitelist_vars.iter() {
+            builder = builder.whitelisted_var(var);
+        }
+        for &ty in whitelist.iter() {
+            builder = builder.whitelisted_type(ty);
+        }
+        for &ty in opaque_types.iter() {
+            builder = builder.opaque_type(ty);
+        }
+        for ty in servo_mapped_generic_types.iter() {
+            let gecko_name = ty.gecko.rsplit("::").next().unwrap();
+            builder = builder.hide_type(ty.gecko)
+                .raw_line(format!("pub type {0}{2} = {1}{2};", gecko_name, ty.servo,
+                                  if ty.generic { "<T>" } else { "" }));
+            fixups.push(Fixup {
+                pat: format!("root::{}", ty.gecko),
+                rep: format!("::gecko_bindings::structs::{}", gecko_name)
+            });
+        }
+        let mut result = builder.generate().expect("Unable to generate bindings").to_string();
+        for fixup in fixups.iter() {
+            result = Regex::new(&format!(r"\b{}\b", fixup.pat)).unwrap().replace_all(&result, fixup.rep.as_str());
+        }
+        File::create(&OUTDIR_PATH.join(structs_file(build_type))).unwrap()
+            .write_all(&result.into_bytes()).unwrap();
+    }
+
+    pub fn generate_bindings() {
+        let mut builder = Builder::get_initial_builder(BuildType::Release)
+            .disable_name_namespacing()
+            .with_codegen_config(CodegenConfig {
+                functions: true,
+                ..CodegenConfig::nothing()
+            })
+            .header(add_include("mozilla/ServoBindings.h"))
+            .hide_type("nsACString_internal")
+            .hide_type("nsAString_internal")
+            .raw_line("pub use nsstring::{nsACString, nsAString};")
+            .raw_line("type nsACString_internal = nsACString;")
+            .raw_line("type nsAString_internal = nsAString;")
+            .whitelisted_function("Servo_.*")
+            .whitelisted_function("Gecko_.*");
+        let structs_types = [
+            "RawGeckoDocument",
+            "RawGeckoElement",
+            "RawGeckoNode",
+            "ThreadSafeURIHolder",
+            "ThreadSafePrincipalHolder",
+            "ConsumeStyleBehavior",
+            "LazyComputeBehavior",
+            "SkipRootBehavior",
+            "FontFamilyList",
+            "FontFamilyType",
+            "ServoElementSnapshot",
+            "SheetParsingMode",
+            "StyleBasicShape",
+            "StyleBasicShapeType",
+            "StyleClipPath",
+            "nsCSSKeyword",
+            "nsCSSShadowArray",
+            "nsCSSValue",
+            "nsCSSValueSharedList",
+            "nsChangeHint",
+            "nsCursorImage",
+            "nsFont",
+            "nsIAtom",
+            "nsRestyleHint",
+            "nsStyleBackground",
+            "nsStyleBorder",
+            "nsStyleColor",
+            "nsStyleColumn",
+            "nsStyleContent",
+            "nsStyleContext",
+            "nsStyleCoord",
+            "nsStyleCoord_Calc",
+            "nsStyleCoord_CalcValue",
+            "nsStyleDisplay",
+            "nsStyleEffects",
+            "nsStyleFont",
+            "nsStyleGradient",
+            "nsStyleGradientStop",
+            "nsStyleImage",
+            "nsStyleImageLayers",
+            "nsStyleImageLayers_Layer",
+            "nsStyleImageLayers_LayerType",
+            "nsStyleImageRequest",
+            "nsStyleList",
+            "nsStyleMargin",
+            "nsStyleOutline",
+            "nsStylePadding",
+            "nsStylePosition",
+            "nsStyleQuoteValues",
+            "nsStyleSVG",
+            "nsStyleSVGReset",
+            "nsStyleTable",
+            "nsStyleTableBorder",
+            "nsStyleText",
+            "nsStyleTextReset",
+            "nsStyleUIReset",
+            "nsStyleUnion",
+            "nsStyleUnit",
+            "nsStyleUserInterface",
+            "nsStyleVariables",
+            "nsStyleVisibility",
+            "nsStyleXUL",
+            "nscoord",
+            "nsresult",
+        ];
+        struct ArrayType {
+            cpp_type: &'static str,
+            rust_type: &'static str
+        }
+        let array_types = [
+            ArrayType { cpp_type: "uintptr_t", rust_type: "usize" },
+        ];
+        let servo_nullable_arc_types = [
+            "ServoComputedValues",
+            "ServoCssRules",
+            "RawServoStyleSheet",
+            "RawServoDeclarationBlock",
+            "RawServoStyleRule",
+        ];
+        struct ServoOwnedType {
+            name: &'static str,
+            opaque: bool,
+        }
+        let servo_owned_types = [
+            ServoOwnedType { name: "RawServoStyleSet", opaque: true },
+            ServoOwnedType { name: "StyleChildrenIterator", opaque: true },
+            ServoOwnedType { name: "ServoElementSnapshot", opaque: false },
+        ];
+        let servo_immutable_borrow_types = [
+            "RawGeckoNode",
+            "RawGeckoElement",
+            "RawGeckoDocument",
+            "RawServoDeclarationBlockStrong",
+        ];
+        let servo_borrow_types = [
+            "nsCSSValue",
+        ];
+        for &ty in structs_types.iter() {
+            builder = builder.hide_type(ty)
+                .raw_line(format!("use gecko_bindings::structs::{};", ty));
+            // TODO this is hacky, figure out a better way to do it without
+            // hardcoding everything...
+            if ty.starts_with("nsStyle") {
+                builder = builder
+                    .raw_line(format!("unsafe impl Send for {} {{}}", ty))
+                    .raw_line(format!("unsafe impl Sync for {} {{}}", ty));
+            }
+        }
+        for &ArrayType { cpp_type, rust_type } in array_types.iter() {
+            builder = builder.hide_type(format!("nsTArrayBorrowed_{}", cpp_type))
+                .raw_line(format!("pub type nsTArrayBorrowed_{}<'a> = &'a mut ::gecko_bindings::structs::nsTArray<{}>;",
+                                  cpp_type, rust_type))
+        }
+        for &ty in servo_nullable_arc_types.iter() {
+            builder = builder
+                .hide_type(format!("{}Strong", ty))
+                .raw_line(format!("pub type {0}Strong = ::gecko_bindings::sugar::ownership::Strong<{0}>;", ty))
+                .borrowed_type(ty)
+                .zero_size_type(ty);
+        }
+        for &ServoOwnedType { name, opaque } in servo_owned_types.iter() {
+            builder = builder
+                .hide_type(format!("{}Owned", name))
+                .raw_line(format!("pub type {0}Owned = ::gecko_bindings::sugar::ownership::Owned<{0}>;", name))
+                .hide_type(format!("{}OwnedOrNull", name))
+                .raw_line(format!("pub type {0}OwnedOrNull = ::gecko_bindings::sugar::ownership::OwnedOrNull<{0}>;",
+                                  name))
+                .mutable_borrowed_type(name);
+            if opaque {
+                builder = builder.zero_size_type(name);
+            }
+        }
+        for &ty in servo_immutable_borrow_types.iter() {
+            builder = builder.borrowed_type(ty);
+        }
+        for &ty in servo_borrow_types.iter() {
+            builder = builder.mutable_borrowed_type(ty);
+            // Right now the only immutable borrow types are ones which we import
+            // from the |structs| module. As such, we don't need to create an opaque
+            // type with zero_size_type. If we ever introduce immutable borrow types
+            // which _do_ need to be opaque, we'll need a separate mode.
+        }
+        write_binding_file(builder, BINDINGS_FILE);
+    }
+}
+
+#[cfg(not(feature = "bindgen"))]
+mod bindings {
+    use std::fs;
+    use std::path::{Path, PathBuf};
+    use super::common::*;
+
+    lazy_static! {
+        static ref BINDINGS_PATH: PathBuf = Path::new(file!()).parent().unwrap().join("gecko_bindings");
+    }
+
+    pub fn generate_structs(build_type: BuildType) {
+        let file = structs_file(build_type);
+        let source = BINDINGS_PATH.join(file);
+        println!("cargo:rerun-if-changed={}", source.display());
+        fs::copy(source, OUTDIR_PATH.join(file)).unwrap();
+    }
+
+    pub fn generate_bindings() {
+        let source = BINDINGS_PATH.join(BINDINGS_FILE);
+        println!("cargo:rerun-if-changed={}", source.display());
+        fs::copy(source, OUTDIR_PATH.join(BINDINGS_FILE)).unwrap();
+    }
+}
+
+pub fn generate() {
+    use self::common::*;
+    use std::fs;
+    fs::create_dir_all(&*OUTDIR_PATH).unwrap();
+    bindings::generate_structs(BuildType::Debug);
+    bindings::generate_structs(BuildType::Release);
+    bindings::generate_bindings();
+}
diff --git a/components/style/gecko_bindings/mod.rs b/components/style/gecko_bindings/mod.rs
index 7201bdb2668..d86bfb60484 100644
--- a/components/style/gecko_bindings/mod.rs
+++ b/components/style/gecko_bindings/mod.rs
@@ -3,22 +3,23 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #[allow(dead_code, improper_ctypes, non_camel_case_types)]
-pub mod bindings;
+pub mod bindings {
+    include!(concat!(env!("OUT_DIR"), "/gecko/bindings.rs"));
+}
 
 // FIXME: We allow `improper_ctypes` (for now), because the lint doesn't allow
 // foreign structs to have `PhantomData`. We should remove this once the lint
 // ignores this case.
 
-#[cfg(debug_assertions)]
-#[allow(dead_code, improper_ctypes, non_camel_case_types, non_snake_case, non_upper_case_globals)]
-pub mod structs {
-    include!("structs_debug.rs");
-}
-
-#[cfg(not(debug_assertions))]
 #[allow(dead_code, improper_ctypes, non_camel_case_types, non_snake_case, non_upper_case_globals)]
 pub mod structs {
-    include!("structs_release.rs");
+    cfg_if! {
+        if #[cfg(debug_assertions)] {
+            include!(concat!(env!("OUT_DIR"), "/gecko/structs_debug.rs"));
+        } else {
+            include!(concat!(env!("OUT_DIR"), "/gecko/structs_release.rs"));
+        }
+    }
 }
 
 pub mod sugar;
diff --git a/ports/geckolib/Cargo.toml b/ports/geckolib/Cargo.toml
index 0df70bc465b..23e9db63a13 100644
--- a/ports/geckolib/Cargo.toml
+++ b/ports/geckolib/Cargo.toml
@@ -9,6 +9,9 @@ name = "geckoservo"
 path = "lib.rs"
 crate-type = ["staticlib", "rlib"]
 
+[features]
+bindgen = ["style/bindgen"]
+
 [dependencies]
 app_units = "0.3"
 cssparser = {version = "0.7"}
diff --git a/python/servo/build_commands.py b/python/servo/build_commands.py
index 514a8f87e69..a54d667f5f4 100644
--- a/python/servo/build_commands.py
+++ b/python/servo/build_commands.py
@@ -384,6 +384,9 @@ class MachCommands(CommandBase):
     @Command('build-geckolib',
              description='Build a static library of components used by Gecko',
              category='build')
+    @CommandArgument('--with-gecko',
+                     default=None,
+                     help='Build with Gecko dist directory')
     @CommandArgument('--jobs', '-j',
                      default=None,
                      help='Number of jobs to run in parallel')
@@ -393,12 +396,18 @@ class MachCommands(CommandBase):
     @CommandArgument('--release', '-r',
                      action='store_true',
                      help='Build in release mode')
-    def build_geckolib(self, jobs=None, verbose=False, release=False):
+    def build_geckolib(self, with_gecko=None, jobs=None, verbose=False, release=False):
         self.set_use_stable_rust()
         self.ensure_bootstrapped()
 
+        env = self.build_env(is_build=True)
+        env["CARGO_TARGET_DIR"] = path.join(self.context.topdir, "target", "geckolib").encode("UTF-8")
+
         ret = None
         opts = []
+        if with_gecko is not None:
+            opts += ["--features", "bindgen"]
+            env["MOZ_DIST"] = path.abspath(with_gecko)
         if jobs is not None:
             opts += ["-j", jobs]
         if verbose:
@@ -406,9 +415,6 @@ class MachCommands(CommandBase):
         if release:
             opts += ["--release"]
 
-        env = self.build_env(is_build=True)
-        env["CARGO_TARGET_DIR"] = path.join(self.context.topdir, "target", "geckolib").encode("UTF-8")
-
         build_start = time()
         with cd(path.join("ports", "geckolib")):
             ret = call(["cargo", "build"] + opts, env=env, verbose=verbose)