[PING][PATCH V2] plugin event for C/C++ function definitions

[Andres Tiraboschi]

Hi, this patch adds a new plugin event PLUGIN_START_PARSE_FUNCTION and PLUGIN_FINISH_PARSE_FUNCTION that are invoked at start_function and finish_function respectively in the C and C++ frontends. 
PLUGIN_START_PARSE_FUNCTION is called before parsing the function body.
PLUGIN_FINISH_PARSE_FUNCTION is called after parsing a function definition.

Since I have no write privileges please commit this for me if ok.

changelog:

 gcc/c/c-decl.c: Invoke callbacks in start_function and finish_function.                            
 gcc/cp/decl.c: Invoke callbacks in start_function and finish_function.
                                
 gcc/doc/plugins.texi: Add documentation about PLUGIN_START_FUNCTION and PLUGIN_FINISH_FUNCTION
 gcc/plugin.def: Add events for start_function and finish_function.                          
 gcc/plugin.c (register_callback, invoke_plugin_callbacks): Same.

 gcc/testsuite/g++.dg/plugin/def_plugin.c: New test plugin.                                  
 gcc/testsuite/g++.dg/plugin/def-plugin-test.C: Testcase for above plugin.
 gcc/testsuite/g++.dg/plugin/plugin.exp 

diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 6413e6f..d9d922c 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -4449,6 +4449,7 @@ start_decl (struct c_declarator *declarator, struct c_declspecs *declspecs,
   decl = grokdeclarator (declarator, declspecs,
 			 NORMAL, initialized, NULL, &attributes, &expr, NULL,
 			 deprecated_state);
+  invoke_plugin_callbacks (PLUGIN_START_PARSE_FUNCTION, decl);
   if (!decl)
     return 0;
 
@@ -9031,6 +9032,7 @@ finish_function (void)
      It's still in DECL_STRUCT_FUNCTION, and we'll restore it in
      tree_rest_of_compilation.  */
   set_cfun (NULL);
+  invoke_plugin_callbacks (PLUGIN_FINISH_PARSE_FUNCTION, current_function_decl);
   current_function_decl = NULL;
 }
 
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 716ab5f..6adf2e4 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13671,6 +13671,7 @@ start_function (cp_decl_specifier_seq *declspecs,
   tree decl1;
 
   decl1 = grokdeclarator (declarator, declspecs, FUNCDEF, 1, &attrs);
+  invoke_plugin_callbacks (PLUGIN_START_PARSE_FUNCTION, decl1);
   if (decl1 == error_mark_node)
     return false;
   /* If the declarator is not suitable for a function definition,
@@ -14301,6 +14302,7 @@ finish_function (int flags)
       vec_free (deferred_mark_used_calls);
     }
 
+  invoke_plugin_callbacks (PLUGIN_FINISH_PARSE_FUNCTION, fndecl);
   return fndecl;
 }
 
diff --git a/gcc/doc/plugins.texi b/gcc/doc/plugins.texi
index 4a839b8..1c9e074 100644
--- a/gcc/doc/plugins.texi
+++ b/gcc/doc/plugins.texi
@@ -174,6 +174,8 @@ Callbacks can be invoked at the following pre-determined events:
 @smallexample
 enum plugin_event
 @{
+  PLUGIN_START_PARSE_FUNCTION,  /* Called before parsing the body of a function. */
+  PLUGIN_FINISH_PARSE_FUNCTION, /* After finishing parsing a function. */
   PLUGIN_PASS_MANAGER_SETUP,    /* To hook into pass manager.  */
   PLUGIN_FINISH_TYPE,           /* After finishing parsing a type.  */
   PLUGIN_FINISH_DECL,           /* After finishing parsing a declaration. */
diff --git a/gcc/plugin.c b/gcc/plugin.c
index 8debc09..f7a8b64 100644
--- a/gcc/plugin.c
+++ b/gcc/plugin.c
@@ -433,6 +433,8 @@ register_callback (const char *plugin_name,
 	    return;
 	  }
       /* Fall through.  */
+      case PLUGIN_START_PARSE_FUNCTION:
+      case PLUGIN_FINISH_PARSE_FUNCTION:
       case PLUGIN_FINISH_TYPE:
       case PLUGIN_FINISH_DECL:
       case PLUGIN_START_UNIT:
@@ -511,6 +513,8 @@ invoke_plugin_callbacks_full (int event, void *gcc_data)
 	gcc_assert (event >= PLUGIN_EVENT_FIRST_DYNAMIC);
 	gcc_assert (event < event_last);
       /* Fall through.  */
+      case PLUGIN_START_PARSE_FUNCTION:
+      case PLUGIN_FINISH_PARSE_FUNCTION:
       case PLUGIN_FINISH_TYPE:
       case PLUGIN_FINISH_DECL:
       case PLUGIN_START_UNIT:
diff --git a/gcc/plugin.def b/gcc/plugin.def
index df5d383..4b7f6ef 100644
--- a/gcc/plugin.def
+++ b/gcc/plugin.def
@@ -17,6 +17,11 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+/* Called before parsing the body of a function.  */
+DEFEVENT (PLUGIN_START_PARSE_FUNCTION)
+
+/* After finishing parsing a function. */
+DEFEVENT (PLUGIN_FINISH_PARSE_FUNCTION)
 
 /* To hook into pass manager.  */
 DEFEVENT (PLUGIN_PASS_MANAGER_SETUP)
diff --git a/gcc/testsuite/g++.dg/plugin/def-plugin-test.C b/gcc/testsuite/g++.dg/plugin/def-plugin-test.C
new file mode 100644
index 0000000..b7f2d3d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/plugin/def-plugin-test.C
@@ -0,0 +1,13 @@
+int global = 12;
+
+int function1(void);
+
+int function2(int a) // { dg-warning "Start fndef function2" }
+{
+  return function1() + a;
+} //  { dg-warning "Finish fndef function2" }
+
+int function1(void) // { dg-warning "Start fndef function1" }
+{
+  return global + 1;
+} //  { dg-warning "Finish fndef function1" }
diff --git a/gcc/testsuite/g++.dg/plugin/def_plugin.c b/gcc/testsuite/g++.dg/plugin/def_plugin.c
new file mode 100644
index 0000000..63983c5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/plugin/def_plugin.c
@@ -0,0 +1,45 @@
+/* A plugin example that shows which function definitions are caught by PLUGIN_START_FUNCTION and PLUGIN_FINISH_FUNCTION */
+
+#include "gcc-plugin.h"
+#include <stdlib.h>
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "tree-pass.h"
+#include "intl.h"
+#include "diagnostic.h"
+
+int plugin_is_GPL_compatible;
+
+/* Callback function to invoke when GCC starts a function definition*/
+
+void plugin_start_parse_function (void *event_data, void *data)
+{
+  tree fndef = (tree) event_data;
+  warning (0, G_("Start fndef %s"),
+           IDENTIFIER_POINTER (DECL_NAME (fndef)));
+}
+
+/* Callback function to invoke after GCC finishes a function definition. */
+
+void plugin_finish_parse_function (void *event_data, void *data)
+{
+  tree fndef = (tree) event_data;
+  warning (0, G_("Finish fndef %s"),
+           IDENTIFIER_POINTER (DECL_NAME (fndef)));
+}
+
+int
+plugin_init (struct plugin_name_args *plugin_info,
+             struct plugin_gcc_version *version)
+{
+  const char *plugin_name = plugin_info->base_name;
+
+  register_callback (plugin_name, PLUGIN_START_PARSE_FUNCTION,
+                     plugin_start_parse_function, NULL);
+
+  register_callback (plugin_name, PLUGIN_FINISH_PARSE_FUNCTION,
+                     plugin_finish_parse_function, NULL);
+  return 0;
+}
diff --git a/gcc/testsuite/g++.dg/plugin/plugin.exp b/gcc/testsuite/g++.dg/plugin/plugin.exp
index f3fd8ee..21cac6a 100644
--- a/gcc/testsuite/g++.dg/plugin/plugin.exp
+++ b/gcc/testsuite/g++.dg/plugin/plugin.exp
@@ -61,7 +61,8 @@ set plugin_test_list [list \
     { selfassign.c self-assign-test-1.C self-assign-test-2.C self-assign-test-3.C } \
     { dumb_plugin.c dumb-plugin-test-1.C } \
     { header_plugin.c header-plugin-test.C } \
-    { decl_plugin.c decl-plugin-test.C } ]
+    { decl_plugin.c decl-plugin-test.C } \
+    { def_plugin.c def-plugin-test.C } ]
 
 foreach plugin_test $plugin_test_list {
     # Replace each source file with its full-path name