set path for pkg-config when using sysroot

common.gypi

@@ -260,5 +260,11 @@
         },
       },
     }],  # OS=="mac"
+
+    ['OS=="linux"', {
+      'variables': {
+        'pkg-config': '<(source_root)/tools/linux/pkg-config-wrapper "<(sysroot)" "<(target_arch)" "<(system_libdir)"',
+      },
+    }], # OS=="linux"
   ],
 }

toolchain.gypi

@@ -5,8 +5,7 @@
     # Set this to true when building with Clang.
     'clang%': 1,
 
-    # Path to sysroot dir.
+    'system_libdir%': 'lib',
-    'sysroot%': '',
 
     'variables': {
       # The minimum OS X SDK version to use.
@@ -17,12 +16,20 @@
 
       # Set NEON compilation flags.
       'arm_neon%': 1,
+
+      'conditions': [
+        # Define the abosulte version of <(DEPTH).
+        ['OS!="win"', {
+          'source_root%': '<!(cd <(DEPTH) && pwd -P)',
+        }],  # OS!="win"
+      ],
     },
 
     # Copy conditionally-set variables out one scope.
     'mac_sdk_min%': '<(mac_sdk_min)',
     'arm_version%': '<(arm_version)',
     'arm_neon%': '<(arm_neon)',
+    'source_root%': '<(source_root)',
 
     # Variables to control Link-Time Optimization (LTO).
     'use_lto%': 0,
@@ -34,16 +41,29 @@
         'clang%': 0,
       }],  # OS=="win"
 
-      # Define the abosulte version of <(DEPTH).
-      ['OS!="win"', {
-        'source_root': '<!(cd <(DEPTH) && pwd -P)',
-      }],  # OS!="win"
-
       # Search for the available version of SDK.
       ['OS=="mac"', {
         'mac_sdk%': '<!(python <(DEPTH)/tools/mac/find_sdk.py <(mac_sdk_min))',
       }],
 
+      ['OS=="linux"', {
+        'conditions': [
+          ['target_arch=="arm"', {
+            # sysroot needs to be an absolute path otherwise it generates
+            # incorrect results when passed to pkg-config
+            'sysroot%': '<(source_root)/vendor/debian_wheezy_arm-sysroot',
+          }],
+          ['target_arch=="ia32"', {
+            'sysroot%': '<(source_root)/vendor/debian_wheezy_i386-sysroot',
+          }],
+          ['target_arch=="x64"', {
+            'sysroot%': '<(source_root)/vendor/debian_wheezy_amd64-sysroot',
+          }],
+        ],
+      }, {
+        'sysroot%': ' ',
+      }],
+
       # Set default compiler flags depending on ARM version.
       ['arm_version==6', {
         'arm_arch%': 'armv6',
@@ -114,21 +134,6 @@
 
     # Setup sysroot environment.
     ['OS=="linux" and target_arch in ["arm", "ia32", "x64"]', {
-      'variables': {
-        'conditions': [
-          ['target_arch=="arm"', {
-            # sysroot needs to be an absolute path otherwise it generates
-            # incorrect results when passed to pkg-config
-            'sysroot': '<(source_root)/vendor/debian_wheezy_arm-sysroot',
-          }],
-          ['target_arch=="ia32"', {
-            'sysroot': '<(source_root)/vendor/debian_wheezy_i386-sysroot',
-          }],
-          ['target_arch=="x64"', {
-            'sysroot': '<(source_root)/vendor/debian_wheezy_amd64-sysroot',
-          }],
-        ],
-      },
       'target_defaults': {
         'target_conditions': [
           ['_toolset=="target"', {
@@ -142,7 +147,7 @@
           }]
         ],
       },
-    }],  # target_arch==arm
+    }],  # sysroot
 
     # Setup cross-compilation on Linux.
     ['OS=="linux"', {

tools/linux/pkg-config-wrapper

@@ -0,0 +1,49 @@
+#!/bin/bash
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This program wraps around pkg-config to generate the correct include and
+# library paths when cross-compiling using a sysroot.
+# The assumption is that the sysroot contains the .pc files in usr/lib/pkgconfig
+# and usr/share/pkgconfig (relative to the sysroot) and that they output paths
+# relative to some parent path of the sysroot.
+# This assumption is valid for a range of sysroots, in particular: a
+# LSB-compliant root filesystem mounted at the sysroot, and a board build
+# directory of a Chromium OS chroot.
+# Additional directories containing .pc files may be specified by setting
+# the PKG_CONFIG_PATH environment variable- these will be prepended to the
+# generated paths.
+
+set -o nounset
+set -o errexit
+
+root="$1"
+shift
+target_arch="$1"
+shift
+libpath="$1"
+shift
+
+if [ -z "$root" -o -z "$target_arch" ]
+then
+  echo "usage: $0 /path/to/sysroot target_arch libdir [pkg-config-arguments] package" >&2
+  exit 1
+fi
+
+rewrite=`dirname $0`/rewrite_dirs.py
+package=${!#}
+
+libdir=$root/usr/$libpath/pkgconfig:$root/usr/share/pkgconfig
+
+set -e
+# Some sysroots, like the Chromium OS ones, may generate paths that are not
+# relative to the sysroot. For example,
+# /path/to/chroot/build/x86-generic/usr/lib/pkgconfig/pkg.pc may have all paths
+# relative to /path/to/chroot (i.e. prefix=/build/x86-generic/usr) instead of
+# relative to /path/to/chroot/build/x86-generic (i.e prefix=/usr).
+# To support this correctly, it's necessary to extract the prefix to strip from
+# pkg-config's |prefix| variable.
+prefix=`PKG_CONFIG_LIBDIR=$libdir pkg-config --variable=prefix "$package" | sed -e 's|/usr$||'`
+result=`PKG_CONFIG_LIBDIR=$libdir pkg-config "$@"`
+echo "$result"| $rewrite --sysroot "$root" --strip-prefix "$prefix"

tools/linux/rewrite_dirs.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Rewrites paths in -I, -L and other option to be relative to a sysroot."""
+
+import sys
+import os
+import optparse
+
+REWRITE_PREFIX = ['-I',
+                  '-idirafter',
+                  '-imacros',
+                  '-imultilib',
+                  '-include',
+                  '-iprefix',
+                  '-iquote',
+                  '-isystem',
+                  '-L']
+
+def RewritePath(path, opts):
+  """Rewrites a path by stripping the prefix and prepending the sysroot."""
+  sysroot = opts.sysroot
+  prefix = opts.strip_prefix
+  if os.path.isabs(path) and not path.startswith(sysroot):
+    if path.startswith(prefix):
+      path = path[len(prefix):]
+    path = path.lstrip('/')
+    return os.path.join(sysroot, path)
+  else:
+    return path
+
+
+def RewriteLine(line, opts):
+  """Rewrites all the paths in recognized options."""
+  args = line.split()
+  count = len(args)
+  i = 0
+  while i < count:
+    for prefix in REWRITE_PREFIX:
+      # The option can be either in the form "-I /path/to/dir" or
+      # "-I/path/to/dir" so handle both.
+      if args[i] == prefix:
+        i += 1
+        try:
+          args[i] = RewritePath(args[i], opts)
+        except IndexError:
+          sys.stderr.write('Missing argument following %s\n' % prefix)
+          break
+      elif args[i].startswith(prefix):
+        args[i] = prefix + RewritePath(args[i][len(prefix):], opts)
+    i += 1
+
+  return ' '.join(args)
+
+
+def main(argv):
+  parser = optparse.OptionParser()
+  parser.add_option('-s', '--sysroot', default='/', help='sysroot to prepend')
+  parser.add_option('-p', '--strip-prefix', default='', help='prefix to strip')
+  opts, args = parser.parse_args(argv[1:])
+
+  for line in sys.stdin.readlines():
+    line = RewriteLine(line.strip(), opts)
+    print line
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))