Linux: create a library loader code generator for dlopen and use it for libpci.

content/content_gpu.gypi

Index: content/content_gpu.gypi
diff --git a/content/content_gpu.gypi b/content/content_gpu.gypi
index 6b05cded06fe05e42c8b4a30a9eec2341c5bd208..b4901a8023c067bd3a03da099cd33786bfaf6b80 100644
--- a/content/content_gpu.gypi
+++ b/content/content_gpu.gypi
@@ -48,6 +48,45 @@
         ],
       },
     }],
+    ['OS=="linux"', {
+      'cflags': [
+        '<!@(pkg-config --cflags libpci)',

[piman, 2012/11/27 00:09:18]

You need to go through the pkg-config indirection for sysroots (see
build/linux/system.gyp)

[Paweł Hajdan Jr., 2012/11/27 19:52:18]

Done.

+      ],
+      'sources': [
+        '<(INTERMEDIATE_DIR)/libpci_loader.cc',
+      ],
+      'include_dirs': [
+        '<(INTERMEDIATE_DIR)',
+      ],
+      'hard_dependency': 1,

[piman, 2012/11/27 00:09:18]

Is that really needed? That prevents a ton of build parallelization (essentially
forces a build barrier between content's dependencies and content, as well as
between content and content's dependent).
Could we separate this into its own target? This would maximize parallelization
(this can happen in parallel with content's dependencies building)

[Paweł Hajdan Jr., 2012/11/27 19:52:18]

Done.

+      'actions': [
+        {
+          'action_name': 'generate_libpci_loader',
+          'inputs': [
+            '../tools/generate_library_loader/generate_library_loader.py',
+          ],
+          'outputs': [
+            '<(INTERMEDIATE_DIR)/libpci_loader.cc',
+            '<(INTERMEDIATE_DIR)/libpci_loader.h',
+          ],
+          'action': ['python',
+                     '../tools/generate_library_loader/generate_library_loader.py',
+                     '--name', 'LibPciLoader',
+                     '--output', '<(INTERMEDIATE_DIR)/libpci_loader',
+                     '--header', '<pci/pci.h>',
+                     '--use-extern-c',
+                     '--link-directly=<(linux_link_libpci)',
+                     'pci_alloc',
+                     'pci_init',
+                     'pci_cleanup',
+                     'pci_scan_bus',
+                     'pci_fill_info',
+                     'pci_lookup_name',
+          ],
+          'message': 'Generating libpci library loader.',
+        },
+      ],
+    }],
     ['OS=="win" and directxsdk_exists=="True"', {
       'actions': [
         {
@@ -113,14 +152,7 @@
         '<(DEPTH)/third_party/libva',
       ],
     }],
-    ['linux_link_libpci==0', {
-      'defines': [
-        'DLOPEN_LIBPCI',
-      ],
-    }, { # linux_link_libpci==1
-      'cflags': [
-        '<!@(pkg-config --cflags libpci)',
-      ],
+    ['linux_link_libpci==1', {
       'link_settings': {
         'ldflags': [
           '<!@(pkg-config --libs-only-L --libs-only-other libpci)',