Add support for detecting mismatched allocation/deallocation calls.

PR c++/90629 - Support for -Wmismatched-new-delete
PR middle-end/94527 - Add an __attribute__ that marks a function as freeing an object

gcc/ChangeLog:

	PR c++/90629
	PR middle-end/94527
	* builtins.c (access_ref::access_ref): Initialize new member.
	(compute_objsize): Use access_ref::deref.  Handle simple pointer
	assignment.
	(expand_builtin): Remove handling of the free built-in.
	(call_dealloc_argno): Same.
	(find_assignment_location): New function.
	(fndecl_alloc_p): Same.
	(gimple_call_alloc_p): Same.
	(call_dealloc_p): Same.
	(matching_alloc_calls_p): Same.
	(warn_dealloc_offset): Same.
	(maybe_emit_free_warning): Same.
	* builtins.h (struct access_ref): Declare new member.
	(maybe_emit_free_warning): Make extern.  Make use of access_ref.
	Handle -Wmismatched-new-delete.
	* calls.c (initialize_argument_information): Call
	maybe_emit_free_warning.
	* doc/extend.texi (attribute malloc): Update.
	* doc/invoke.texi (-Wfree-nonheap-object): Expand documentation.
	(-Wmismatched-new-delete): Document new option.
	(-Wmismatched-dealloc): Document new option.

gcc/c-family/ChangeLog:

	PR c++/90629
	PR middle-end/94527
	* c-attribs.c (handle_dealloc_attribute): New function.
	(handle_malloc_attribute): Handle argument forms of attribute.
	* c.opt (-Wmismatched-dealloc): New option.
	(-Wmismatched-new-delete): New option.

gcc/testsuite/ChangeLog:

	PR c++/90629
	PR middle-end/94527
	* g++.dg/asan/asan_test.cc: Fix a bug.
	* g++.dg/warn/delete-array-1.C: Add expected warning.
	* g++.old-deja/g++.other/delete2.C: Add expected warning.
	* g++.dg/warn/Wfree-nonheap-object-2.C: New test.
	* g++.dg/warn/Wfree-nonheap-object.C: New test.
	* g++.dg/warn/Wmismatched-new-delete.C: New test.
	* g++.dg/warn/Wmismatched-dealloc-2.C: New test.
	* g++.dg/warn/Wmismatched-dealloc.C: New test.
	* gcc.dg/Wmismatched-dealloc.c: New test.
	* gcc.dg/analyzer/malloc-1.c: Prune out expected warning.
	* gcc.dg/attr-malloc.c: New test.
	* gcc.dg/free-1.c: Adjust text of expected warning.
	* gcc.dg/free-2.c: Same.
	* gcc.dg/torture/pr71816.c: Prune out expected warning.
	* gcc.dg/tree-ssa/pr19831-2.c: Add an expected warning.
	* gcc.dg/Wfree-nonheap-object-2.c: New test.
	* gcc.dg/Wfree-nonheap-object-3.c: New test.
	* gcc.dg/Wfree-nonheap-object.c: New test.

libstdc++-v3/ChangeLog:

	* testsuite/ext/vstring/modifiers/clear/56166.cc: Suppress a false
	positive warning.

1 files changed, 10 insertions, 0 deletions

diff --git a/gcc/builtins.h b/gcc/builtins.h
index 09379e8..6429232 100644
--- a/gcc/builtins.h
+++ b/gcc/builtins.h
@@ -220,6 +220,12 @@ struct access_ref
      argument to the minimum.  */
   offset_int size_remaining (offset_int * = NULL) const;
 
+  /* Return true if *THIS is an access to a declared object.  */
+  bool ref_declared () const
+  {
+    return DECL_P (ref) && base0 && deref < 1;
+  }
+
   /* Set the size range to the maximum.  */
   void set_max_size_range ()
   {
@@ -261,6 +267,9 @@ struct access_ref
 
   /* Used to fold integer expressions when called from front ends.  */
   tree (*eval)(tree);
+  /* Positive when REF is dereferenced, negative when its address is
+     taken.  */
+  int deref;
   /* Set if trailing one-element arrays should be treated as flexible
      array members.  */
   bool trail1special;
@@ -350,5 +359,6 @@ extern tree compute_objsize (tree, int, tree * = NULL, tree * = NULL,
 			     range_query * = NULL);
 extern bool check_access (tree, tree, tree, tree, tree,
 			  access_mode, const access_data * = NULL);
+extern void maybe_emit_free_warning (tree);
 
 #endif /* GCC_BUILTINS_H */