PNaCl PPAPI shims: Update for new PNaCl ABI for by-value struct passing

The PNaCl ABI is changing so that by-value struct arguments (and
return values) are expanded out to being passed by pointer, on all
architectures.

This means that __attribute__((pnaclcall)) no longer reflects PNaCl
user code's calling conventions, so we have to change the PNaCl PPAPI
shims.  The new shims can be pure C without any special attributes.

Remove now-unused ptr_prefix argument.

This updates nacl_revision to pull in the following NaCl changes:
r11238: (kschimpf) Update pnacl_llvm_rev to 5712db994c8a4abb8c2512fb2900650f8335af66.
r11239: (mseaborn) Update PNaCl toolchain revision in TOOL_REVISIONS to get ExpandByVal

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3400
TEST=cd ppapi/generators && ./generator.py + compile shims
  + "ppapi/generators/idl_gen_pnacl.py --test"

Review URL: https://codereview.chromium.org/14134011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196881 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 111 insertions, 81 deletions

diff --git a/ppapi/generators/idl_c_proto.py b/ppapi/generators/idl_c_proto.py
index 79656308..fff3e65 100755
--- a/ppapi/generators/idl_c_proto.py
+++ b/ppapi/generators/idl_c_proto.py
@@ -398,7 +398,7 @@ class CGen(object):
 
 
   def Compose(self, rtype, name, arrayspec, callspec, prefix, func_as_ptr,
-              ptr_prefix, include_name, unsized_as_ptr):
+              include_name, unsized_as_ptr):
     self.LogEnter('Compose: %s %s' % (rtype, name))
     arrayspec = ''.join(arrayspec)
 
@@ -417,10 +417,10 @@ class CGen(object):
       params = []
       for ptype, pname, parray, pspec in callspec:
         params.append(self.Compose(ptype, pname, parray, pspec, '', True,
-                                   ptr_prefix='', include_name=True,
+                                   include_name=True,
                                    unsized_as_ptr=unsized_as_ptr))
       if func_as_ptr:
-        name = '(%s*%s)' % (ptr_prefix, name)
+        name = '(*%s)' % name
       if not params:
         params = ['void']
       out = '%s %s(%s)' % (rtype, name, ', '.join(params))
@@ -433,14 +433,13 @@ class CGen(object):
   # Returns the 'C' style signature of the object
   #  prefix - A prefix for the object's name
   #  func_as_ptr - Formats a function as a function pointer
-  #  ptr_prefix - A prefix that goes before the "*" for a function pointer
   #  include_name - If true, include member name in the signature.
-  #                 If false, leave it out. In any case, prefix and ptr_prefix
-  #                 are always included.
+  #                 If false, leave it out. In any case, prefix is always
+  #                 included.
   #  include_version - if True, include version in the member name
   #
   def GetSignature(self, node, release, mode, prefix='', func_as_ptr=True,
-                   ptr_prefix='', include_name=True, include_version=False):
+                   include_name=True, include_version=False):
     self.LogEnter('GetSignature %s %s as func=%s' %
                   (node, mode, func_as_ptr))
     rtype, name, arrayspec, callspec = self.GetComponents(node, release, mode)
@@ -451,7 +450,7 @@ class CGen(object):
     unsized_as_ptr = not callspec
 
     out = self.Compose(rtype, name, arrayspec, callspec, prefix,
-                       func_as_ptr, ptr_prefix, include_name, unsized_as_ptr)
+                       func_as_ptr, include_name, unsized_as_ptr)
 
     self.LogExit('Exit GetSignature: %s' % out)
     return out
diff --git a/ppapi/generators/idl_gen_pnacl.py b/ppapi/generators/idl_gen_pnacl.py
index 35fdafd..1d7dc6e1 100755
--- a/ppapi/generators/idl_gen_pnacl.py
+++ b/ppapi/generators/idl_gen_pnacl.py
@@ -42,7 +42,6 @@ class PnaclGen(WrapperGen):
                         'Generate the PNaCl shim.')
     self.cgen = CGen()
     self._skip_opt = False
-    self._pnacl_attribute = '__attribute__((pnaclcall))'
 
   ############################################################
 
@@ -51,13 +50,6 @@ class PnaclGen(WrapperGen):
     We do not generate the header files.  """
     return 'ppapi/generators/pnacl_shim.h'
 
-  def GetGuardStart(self):
-    return ('\n/* The PNaCl PPAPI shims are only needed on x86-64 and arm. */\n'
-            '#if defined(__x86_64__) || defined(__arm__)\n\n')
-
-  def GetGuardEnd(self):
-    return '\n#endif\n'
-
 
   def InterfaceVersionNeedsWrapping(self, iface, version):
     """Return true if the interface+version has ANY methods that
@@ -108,20 +100,62 @@ class PnaclGen(WrapperGen):
   ############################################################
 
 
+  def ConvertByValueReturnType(self, ret, args_spec):
+    if self.TypeNeedsWrapping(ret, array_dims=[]):
+      args_spec = [(ret, '_struct_result', [], None)] + args_spec
+      ret2 = 'void'
+      wrap_return = True
+    else:
+      ret2 = ret
+      wrap_return = False
+    return wrap_return, ret2, args_spec
+
+
+  def ConvertByValueArguments(self, args_spec):
+    args = []
+    for type_str, name, array_dims, more_args in args_spec:
+      if self.TypeNeedsWrapping(type_str, array_dims):
+        type_str += '*'
+      args.append((type_str, name, array_dims, more_args))
+    return args
+
+
+  def FormatArgs(self, c_operator, args_spec):
+    args = []
+    for type_str, name, array_dims, more_args in args_spec:
+      if self.TypeNeedsWrapping(type_str, array_dims):
+        args.append(c_operator + name)
+      else:
+        args.append(name)
+    return ', '.join(args)
+
+
   def GenerateWrapperForPPBMethod(self, iface, member):
     result = []
     func_prefix = self.WrapperMethodPrefix(iface.node, iface.release)
-    sig = self.cgen.GetSignature(member, iface.release, 'store',
-                                 func_prefix, False)
-    result.append('static %s\n%s {\n' % (self._pnacl_attribute, sig))
-    result.append('  const struct %s *iface = %s.real_iface;\n' %
-                  (iface.struct_name, self.GetWrapperInfoName(iface)))
     ret, name, array, cspec = self.cgen.GetComponents(member,
                                                       iface.release,
                                                       'store')
-    ret_str, args_str = self.GetReturnArgs(ret, cspec)
-    result.append('  %siface->%s(%s);\n}\n\n' % (ret_str,
-                                                 member.GetName(), args_str))
+    wrap_return, ret2, cspec2 = self.ConvertByValueReturnType(ret, cspec)
+    cspec2 = self.ConvertByValueArguments(cspec2)
+    sig = self.cgen.Compose(ret2, name, array, cspec2,
+                            prefix=func_prefix,
+                            func_as_ptr=False,
+                            include_name=True,
+                            unsized_as_ptr=False)
+    result.append('static %s {\n' % sig)
+    result.append('  const struct %s *iface = %s.real_iface;\n' %
+                  (iface.struct_name, self.GetWrapperInfoName(iface)))
+
+    return_prefix = ''
+    if wrap_return:
+      return_prefix = '*_struct_result = '
+    elif ret != 'void':
+      return_prefix = 'return '
+
+    result.append('  %siface->%s(%s);\n}\n\n' % (return_prefix,
+                                                 member.GetName(),
+                                                 self.FormatArgs('*', cspec)))
     return result
 
 
@@ -133,24 +167,35 @@ class PnaclGen(WrapperGen):
     result.append('static %s {\n' % sig)
     result.append('  const struct %s *iface = %s.real_iface;\n' %
                   (iface.struct_name, self.GetWrapperInfoName(iface)))
-    temp_fp = self.cgen.GetSignature(member, iface.release, 'return',
-                                     'temp_fp',
-                                     func_as_ptr=True,
-                                     ptr_prefix=self._pnacl_attribute + ' ',
-                                     include_name=False)
-    cast = self.cgen.GetSignature(member, iface.release, 'return',
-                                  prefix='',
-                                  func_as_ptr=True,
-                                  ptr_prefix=self._pnacl_attribute + ' ',
-                                  include_name=False)
-    result.append('  %s = ((%s)iface->%s);\n' % (temp_fp,
-                                                 cast,
-                                                 member.GetName()))
     ret, name, array, cspec = self.cgen.GetComponents(member,
                                                       iface.release,
                                                       'store')
-    ret_str, args_str = self.GetReturnArgs(ret, cspec)
-    result.append('  %stemp_fp(%s);\n}\n\n' % (ret_str, args_str))
+    wrap_return, ret2, cspec = self.ConvertByValueReturnType(ret, cspec)
+    cspec2 = self.ConvertByValueArguments(cspec)
+    temp_fp = self.cgen.Compose(ret2, name, array, cspec2,
+                                prefix='temp_fp',
+                                func_as_ptr=True,
+                                include_name=False,
+                                unsized_as_ptr=False)
+    cast = self.cgen.Compose(ret2, name, array, cspec2,
+                             prefix='',
+                             func_as_ptr=True,
+                             include_name=False,
+                             unsized_as_ptr=False)
+    result.append('  %s =\n    ((%s)iface->%s);\n' % (temp_fp,
+                                                      cast,
+                                                      member.GetName()))
+    return_prefix = ''
+    if wrap_return:
+      result.append('  %s _struct_result;\n' % ret)
+    elif ret != 'void':
+      return_prefix = 'return '
+
+    result.append('  %stemp_fp(%s);\n' % (return_prefix,
+                                          self.FormatArgs('&', cspec)))
+    if wrap_return:
+      result.append('  return _struct_result;\n')
+    result.append('}\n\n')
     return result
 
 
diff --git a/ppapi/generators/idl_gen_wrapper.py b/ppapi/generators/idl_gen_wrapper.py
index 3e483ac..b828562 100644
--- a/ppapi/generators/idl_gen_wrapper.py
+++ b/ppapi/generators/idl_gen_wrapper.py
@@ -267,21 +267,6 @@ const void *__%(wrapper_prefix)s_PPPGetInterface(const char *name) {
     return '%s_%s_%s_' % (self.wrapper_prefix, release, iface.GetName())
 
 
-  def GetReturnArgs(self, ret_type, args_spec):
-    if ret_type != 'void':
-      ret = 'return '
-    else:
-      ret = ''
-    if args_spec:
-      args = []
-      for arg in args_spec:
-        args.append(arg[1])
-      args = ', '.join(args)
-    else:
-      args = ''
-    return (ret, args)
-
-
   def GenerateWrapperForPPBMethod(self, iface, member):
     result = []
     func_prefix = self.WrapperMethodPrefix(iface.node, iface.release)
@@ -358,7 +343,6 @@ const void *__%(wrapper_prefix)s_PPPGetInterface(const char *name) {
               member, iface.release, 'return',
               prefix='',
               func_as_ptr=True,
-              ptr_prefix='',
               include_name=False)
         else:
           cast = ''
@@ -440,8 +424,6 @@ const void *__%(wrapper_prefix)s_PPPGetInterface(const char *name) {
     # Generate the includes.
     self.GenerateIncludes(iface_releases, out)
 
-    out.Write(self.GetGuardStart())
-
     # Write out static helper functions (mystrcmp).
     self.GenerateHelperFunctions(out)
 
@@ -462,6 +444,5 @@ const void *__%(wrapper_prefix)s_PPPGetInterface(const char *name) {
     # Write out the IDL-invariant functions.
     self.GenerateFixedFunctions(out)
 
-    out.Write(self.GetGuardEnd())
     out.Close()
     return 0
diff --git a/ppapi/generators/test_gen_pnacl/test_interfaces.idl b/ppapi/generators/test_gen_pnacl/test_interfaces.idl
index 78c21eb..f487a76 100644
--- a/ppapi/generators/test_gen_pnacl/test_interfaces.idl
+++ b/ppapi/generators/test_gen_pnacl/test_interfaces.idl
@@ -37,11 +37,11 @@ struct some_struct2 {
 };
 
 /*
- * static __attribute__((pnaclcall)) int32_t
- * Pnacl_M15_PPB_Iface_struct_wrap_foo1(int32_t a, struct some_struct b) {
+ * static int32_t
+ * Pnacl_M15_PPB_Iface_struct_wrap_foo1(int32_t a, struct some_struct* b) {
  *   const struct PPB_Iface_struct_wrap_2_0 *iface =
  *     Pnacl_WrapperInfo_PPB_Iface_struct_wrap_2_0.real_iface;
- *   return iface->foo1(a, b);
+ *   return iface->foo1(a, *b);
  * }
  */
 [version=2.0]
@@ -50,11 +50,11 @@ interface PPB_Iface_struct_wrap {
 };
 
 /*
- * static __attribute__((pnaclcall)) int32_t
- * Pnacl_M15_PPB_Iface_union_wrap_foo1(int32_t a, union some_union b) {
+ * static int32_t
+ * Pnacl_M15_PPB_Iface_union_wrap_foo1(int32_t a, union some_union* b) {
  *   const struct PPB_Iface_union_wrap_2_0 *iface =
  *     Pnacl_WrapperInfo_PPB_Iface_union_wrap_2_0.real_iface;
- *   return iface->foo1(a, b);
+ *   return iface->foo1(a, *b);
  * }
  */
 [version=2.0]
@@ -70,18 +70,19 @@ interface PPB_Iface_nowrap {
 
 
 /*
- * static __attribute__((pnaclcall))
- *   int32_t Pnacl_M13_PPB_SomeWrap_foo1(struct some_struct a) {
+ * static
+ * int32_t Pnacl_M13_PPB_SomeWrap_foo1(struct some_struct* a) {
  *   const struct PPB_SomeWrap_0_0 *iface =
  *     Pnacl_WrapperInfo_PPB_SomeWrap_0_0.real_iface;
- *   return iface->foo1(a);
+ *   return iface->foo1(*a);
  * }
  * 
- * static __attribute__((pnaclcall))
- * struct some_struct Pnacl_M13_PPB_SomeWrap_foo2(int32_t a) {
+ * static
+ * void Pnacl_M13_PPB_SomeWrap_foo2(struct some_struct* _struct_result,
+ *                                  int32_t a) {
  *   const struct PPB_SomeWrap_0_0 *iface =
  *     Pnacl_WrapperInfo_PPB_SomeWrap_0_0.real_iface;
- *   return iface->foo2(a);
+ *   *_struct_result = iface->foo2(a);
  * }
  */
 [version=0.0]
@@ -105,32 +106,36 @@ interface PPB_SomeWrap {
  * static int32_t Pnacl_M13_PPP_SomeWrap_foo1(struct some_struct a) {
  *   const struct PPP_SomeWrap_0_0 *iface =
  *     Pnacl_WrapperInfo_PPP_SomeWrap_0_0.real_iface;
- *   int32_t (__attribute__((pnaclcall)) *temp_fp)(struct some_struct a) =
- *  ((int32_t (__attribute__((pnaclcall)) *)(struct some_struct a))iface->foo1);
- *   return temp_fp(a);
+ *   int32_t (*temp_fp)(struct some_struct* a) =
+ *     ((int32_t (*)(struct some_struct* a))iface->foo1);
+ *   return temp_fp(&a);
  * }
  *
  * static struct some_struct Pnacl_M13_PPP_SomeWrap_foo2(int32_t a) {
  *   const struct PPP_SomeWrap_0_0 *iface =
  *     Pnacl_WrapperInfo_PPP_SomeWrap_0_0.real_iface;
- *   struct some_struct (__attribute__((pnaclcall)) *temp_fp)(int32_t a) =
- *  ((struct some_struct (__attribute__((pnaclcall)) *)(int32_t a))iface->foo2);
- *   return temp_fp(a);
+ *   void (*temp_fp)(struct some_struct* _struct_result, int32_t a) =
+ *     ((void (*)(struct some_struct* _struct_result, int32_t a))iface->foo2);
+ *   struct some_struct _struct_result;
+ *   temp_fp(&_struct_result, a);
+ *   return _struct_result;
  * }
  *
  * static struct some_struct Pnacl_M14_PPP_SomeWrap_foo2(int32_t a) {
  *   const struct PPP_SomeWrap_1_0 *iface =
  *     Pnacl_WrapperInfo_PPP_SomeWrap_1_0.real_iface;
- * struct some_struct (__attribute__((pnaclcall)) *temp_fp)(int32_t a) =
- * ((struct some_struct (__attribute__((pnaclcall)) *)(int32_t a))iface->foo2);
- *   return temp_fp(a);
+ *   void (*temp_fp)(struct some_struct* _struct_result, int32_t a) =
+ *     ((void (*)(struct some_struct* _struct_result, int32_t a))iface->foo2);
+ *   struct some_struct _struct_result;
+ *   temp_fp(&_struct_result, a);
+ *   return _struct_result;
  * }
  *
  * static int32_t Pnacl_M14_PPP_SomeWrap_foo1(const struct some_struct a[]) {
  *   const struct PPP_SomeWrap_1_0 *iface =
  *     Pnacl_WrapperInfo_PPP_SomeWrap_1_0.real_iface;
- *   int32_t (__attribute__((pnaclcall)) *temp_fp)(const struct some_struct a[]) =
- *  ((int32_t (__attribute__((pnaclcall)) *)(const struct some_struct a[]))iface->foo1);
+ *   int32_t (*temp_fp)(const struct some_struct a[]) =
+ *     ((int32_t (*)(const struct some_struct a[]))iface->foo1);
  *   return temp_fp(a);
  * }
  */