Pepper IDL: Check for structs in callbacks.

It's problematic for PNaCl when callbacks take structs that are passed by
value; there's not enough type information for matching GCC's calling
conventions on the target architecture.

This change scans for typedefs that define functions, and scans the arguments
to see if any are a struct (or a typedef of a struct).

This change whitelists one existing problematic callback.

Tested:
  Verified that exceptions are raised for the one type in the whitelist when
the whitelist was empty. Verified that no exceptions are raised with this
change as-is.

BUG=233439

Review URL: https://chromiumcodereview.appspot.com/13973011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196162 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 29 insertions, 0 deletions

diff --git a/ppapi/generators/idl_c_header.py b/ppapi/generators/idl_c_header.py
index 2c3cf2c..4ad27ba 100755
--- a/ppapi/generators/idl_c_header.py
+++ b/ppapi/generators/idl_c_header.py
@@ -139,11 +139,40 @@ def GenerateHeader(out, filenode, releases):
     out.Write(CommentLines(['*',' @}', '']) + '\n')
 
 
+def CheckTypedefs(filenode, releases):
+  """Checks that typedefs don't specify callbacks that take some structs.
+
+  See http://crbug.com/233439 for details.
+  """
+  cgen = CGen()
+  # TODO(teravest): Fix the following callback to pass PP_Var by pointer
+  # instead of by value.
+  node_whitelist = ['PP_Ext_Alarms_OnAlarm_Func_Dev_0_1']
+  for node in filenode.GetListOf('Typedef'):
+    if node.GetName() in node_whitelist:
+      continue
+    build_list = node.GetUniqueReleases(releases)
+    callnode = node.GetOneOf('Callspec')
+    if callnode:
+      for param in callnode.GetListOf('Param'):
+        if param.GetListOf('Array'):
+          continue
+        if cgen.GetParamMode(param) != 'in':
+          continue
+        t = param.GetType(build_list[0])
+        while t.IsA('Typedef'):
+          t = t.GetType(build_list[0])
+        if t.IsA('Struct'):
+          raise Exception('%s is a struct in callback %s. '
+                          'See http://crbug.com/233439' %
+                          (t.GetName(), node.GetName()))
+
 class HGen(GeneratorByFile):
   def __init__(self):
     Generator.__init__(self, 'C Header', 'cgen', 'Generate the C headers.')
 
   def GenerateFile(self, filenode, releases, options):
+    CheckTypedefs(filenode, releases)
     savename = GetHeaderFromNode(filenode, GetOption('dstroot'))
     my_min, my_max = filenode.GetMinMax(releases)
     if my_min > releases[-1] or my_max < releases[0]: