Add experimental support for compiling with clang and ASan on Linux.

build/standalone.gypi

 # Copyright 2014 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Definitions to be used when building stand-alone PDFium binaries.
 
 {
   'variables': {
     'component%': 'static_library',
     'clang%': 0,
+    'asan%': 0,
+    'sanitizer_coverage%': 0,
     'msvs_multi_core_compile%': '1',
     'variables': {
       'variables': {
         'variables': {
           'conditions': [
             ['OS=="linux" or OS=="mac"', {
               # This handles the Unix platforms we generally deal with.
               # Anything else gets passed through, which probably won't work
               # very well; such hosts should pass an explicit target_arch
               # to gyp.
               'host_arch%':
                 '<!(uname -m | sed -e "s/i.86/ia32/;\
                                        s/x86_64/x64/;\
                                        s/amd64/x64/;\
                                        s/arm.*/arm/;\
                                        s/aarch64/arm64/;\
                                        s/mips.*/mipsel/")',
             }, {
               # OS!="linux" and OS!="mac"
               'host_arch%': 'ia32',
             }],
           ],
         },
         'host_arch%': '<(host_arch)',
         'target_arch%': '<(host_arch)',
       },
       'host_arch%': '<(host_arch)',
       'target_arch%': '<(target_arch)',
     },
+    'clang_dir%': 'third_party/llvm-build/Release+Asserts',
     # These two are needed by V8.
     'host_arch%': '<(host_arch)',
     'target_arch%': '<(target_arch)',
     'werror%': '-Werror',
     'v8_optimized_debug%': 0,
     'v8_use_external_startup_data%': 0,
     'icu_gyp_path': '../v8/third_party/icu/icu.gyp',
     'conditions': [
       ['OS == "win"', {
         'os_posix%': 0,
       }, {
         'os_posix%': 1,
       }],
+      ['OS=="linux" or OS=="mac"', {
+        'clang%': 1,
+      }, {
+        'clang%': 0,
+      }],
     ],
   },
   'target_defaults': {
     'default_configuration': 'Debug',
     'configurations': {
       'Debug': {
         'cflags': [
           '-g',
           '-O0',
           '-fdata-sections',
@@ skipping 91 matching lines @@
       '-fvisibility=hidden',
     ],
     'cflags_cc': [
       '-std=gnu++0x',
       '-Wnon-virtual-dtor',
       '-fno-rtti',
     ],
     'ldflags': [
       '-pthread',
     ],
+    'conditions': [
+      ['asan==1', {
+        'cflags': [
+          '-fsanitize=address',
+          '-gline-tables-only',
+        ],
+        'ldflags': [
+          '-fsanitize=address',
+        ],
+      }],
+      ['sanitizer_coverage!=0', {
+        'cflags': [
+          '-fsanitize-coverage=<(sanitizer_coverage)',
+        ],
+      }],
+    ],
     'defines': [
       # Don't use deprecated V8 APIs anywhere.
       'V8_DEPRECATION_WARNINGS',
     ],
     'msvs_cygwin_dirs': ['<(DEPTH)/v8/third_party/cygwin'],
     'msvs_configuration_attributes': {
       'OutputDirectory': '<(DEPTH)\\build\\$(ConfigurationName)',
       'IntermediateDirectory': '$(OutDir)\\obj\\$(ProjectName)',
       'CharacterSet': '1',
     },
@@ skipping 69 matching lines @@
         '-Wno-unused-parameter',
       ],
     },
   },
   'conditions': [
     ['component=="shared_library"', {
       'cflags': [
         '-fPIC',
       ],
     }],
+    ['OS=="linux" or OS=="mac"', {
+      'conditions': [
+        ['clang==1', {
+          'make_global_settings': [
+            ['CC', '<(clang_dir)/bin/clang'],
+            ['CXX', '<(clang_dir)/bin/clang++'],
+          ],
+        }],
+      ],
+    }],  # OS=="linux" or OS=="mac"
     ['OS=="win"', {
       'target_defaults': {
         'defines': [
           'NOMINMAX',
           '_CRT_SECURE_NO_DEPRECATE',
           '_CRT_NONSTDC_NO_DEPRECATE',
         ],
         'conditions': [
           ['component=="static_library"', {
             'defines': [
@@ skipping 18 matching lines @@
           'V8_USE_EXTERNAL_STARTUP_DATA',
         ],
       },
     }],  # v8_use_external_startup_data==1
   ],
   'xcode_settings': {
     # See comment in Chromium's common.gypi for why this is needed.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   }
 }