Properly separate host and target builds when using external natives.

tools/gyp/v8.gyp

Index: tools/gyp/v8.gyp
diff --git a/tools/gyp/v8.gyp b/tools/gyp/v8.gyp
index 3b832852e3b40f2a6f2dbdd2af6f5519d50d2293..5c9ff3b6314b736f34739fb65a9be1fcae30e25f 100644
--- a/tools/gyp/v8.gyp
+++ b/tools/gyp/v8.gyp
@@ -55,11 +55,23 @@
           # to appear before libv8_snapshot.a so it's listed explicitly.
           'dependencies': ['v8_base', 'v8_nosnapshot'],
         }],
-        ['v8_use_external_startup_data==1 and want_separate_host_toolset==0', {
+        ['v8_use_external_startup_data==1 and want_separate_host_toolset==1', {
           'dependencies': ['v8_base', 'v8_external_snapshot'],
+          'target_conditions': [
+            ['_toolset=="host"', {
+              'inputs': [
+                '<(PRODUCT_DIR)/snapshot_blob_host.bin',
+              ],
+            }, {
+              'inputs': [
+                '<(PRODUCT_DIR)/snapshot_blob.bin',
+              ],
+            }],
+          ],
         }],
-        ['v8_use_external_startup_data==1 and want_separate_host_toolset==1', {
-          'dependencies': ['v8_base', 'v8_external_snapshot#host'],
+        ['v8_use_external_startup_data==1 and want_separate_host_toolset==0', {
+          'dependencies': ['v8_base', 'v8_external_snapshot'],
+          'inputs': [ '<(PRODUCT_DIR)/snapshot_blob.bin', ],
         }],
         ['component=="shared_library"', {
           'type': '<(component)',
@@ -218,11 +230,11 @@
       'type': 'static_library',
       'conditions': [
         ['want_separate_host_toolset==1', {
-          'toolsets': ['host'],
+          'toolsets': ['host', 'target'],
           'dependencies': [
             'mksnapshot#host',
             'js2c#host',
-            'natives_blob#host',
+            'natives_blob',
         ]}, {
           'toolsets': ['target'],
           'dependencies': [
@@ -260,9 +272,27 @@
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)mksnapshot<(EXECUTABLE_SUFFIX)',
           ],
-          'outputs': [
-            '<(INTERMEDIATE_DIR)/snapshot.cc',
-            '<(PRODUCT_DIR)/snapshot_blob.bin',
+          'conditions': [
+            ['want_separate_host_toolset==1', {
+              'target_conditions': [
+                ['_toolset=="host"', {
+                  'outputs': [
+                    '<(INTERMEDIATE_DIR)/snapshot.cc',
+                    '<(PRODUCT_DIR)/snapshot_blob_host.bin',

[vogelheim, 2014/08/29 14:10:55]

I'm a bit skeptical here: snapshot.cc and snapshot_blob.bin represent largely
the same data, but in a different format: One as constants in C, the other as a
blob file. So if we disambiguate between the host and target blob file, we would
probably also disambiguate the equivalent .cc file.

Admittedly this is more pattern matching than a specific problem this might
cause, but... well.

[rmcilroy, 2014/08/29 14:15:47]

I think the difference is that snapshot.cc is already disambiguated between host
/ target because it is in <(INTERMEDIATE_DIR) (which is different for host and
target), whereas <(PRODUCT_DIR) is the same for both the host / target builds
and so has to be explicitly differentiated.

[vogelheim, 2014/08/29 14:55:39]

Ah, yes, that makes sense. Thanks for the explanation!

+                  ],
+                }, {
+                  'outputs': [
+                    '<(INTERMEDIATE_DIR)/snapshot.cc',
+                    '<(PRODUCT_DIR)/snapshot_blob.bin',
+                  ],
+                }],
+              ],
+            }, {
+              'outputs': [
+                '<(INTERMEDIATE_DIR)/snapshot.cc',
+                '<(PRODUCT_DIR)/snapshot_blob.bin',
+              ],
+            }],
           ],
           'variables': {
             'mksnapshot_flags': [
@@ -1344,7 +1374,13 @@
       'type': 'none',
       'conditions': [
         [ 'v8_use_external_startup_data==1', {
-          'dependencies': ['js2c'],
+          'conditions': [
+            ['want_separate_host_toolset==1', {
+              'dependencies': ['js2c#host'],
+            }, {
+              'dependencies': ['js2c'],
+            }],
+          ],
           'actions': [{
             'action_name': 'concatenate_natives_blob',
             'inputs': [
@@ -1352,14 +1388,38 @@
               '<(SHARED_INTERMEDIATE_DIR)/libraries.bin',
               '<(SHARED_INTERMEDIATE_DIR)/libraries-experimental.bin',
             ],
-            'outputs': [
-              '<(PRODUCT_DIR)/natives_blob.bin',
+            'conditions': [
+              ['want_separate_host_toolset==1', {
+                'target_conditions': [
+                  ['_toolset=="host"', {
+                    'outputs': [
+                      '<(PRODUCT_DIR)/natives_blob_host.bin',
+                    ],
+                    'action': [
+                      'python', '<@(_inputs)', '<(PRODUCT_DIR)/natives_blob_host.bin'
+                    ],
+                  }, {
+                    'outputs': [
+                      '<(PRODUCT_DIR)/natives_blob.bin',
+                    ],
+                    'action': [
+                      'python', '<@(_inputs)', '<(PRODUCT_DIR)/natives_blob.bin'
+                    ],
+                  }],
+                ],
+              }, {
+                'outputs': [
+                  '<(PRODUCT_DIR)/natives_blob.bin',
+                ],
+                'action': [
+                  'python', '<@(_inputs)', '<(PRODUCT_DIR)/natives_blob.bin'
+                ],
+              }],
             ],
-            'action': ['python', '<@(_inputs)', '<@(_outputs)'],
           }],
         }],
         ['want_separate_host_toolset==1', {
-          'toolsets': ['host'],
+          'toolsets': ['host', 'target'],
         }, {
           'toolsets': ['target'],
         }],