Patchwork C++ PATCH for c++/48008 (mangling clash with -fabi-version=5)

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Submitter Jason Merrill
Date March 7, 2011, 8:08 p.m.
Message ID <4D753B51.1040208@redhat.com>
Download mbox | patch
Permalink /patch/85796/
State New
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Comments

Jason Merrill - March 7, 2011, 8:08 p.m.
My patch from last July to avoid mangling attribute const/volatile as 
qualifiers on the type had the unfortunate effect of also omitting 
const/volatile function-cv-quals on plain function types, which can 
occur as template arguments.  This patch fixes that by stripping the 
attribute-derived qualifiers on pointer/reference-to-function types, 
where the function-cv-quals cannot occur.

Tested x86_64-pc-linux-gnu, applied to trunk.
commit 5f2add86f317fdc58ca590401baf873908043672
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Mar 7 13:03:12 2011 -0500

    	PR c++/48008
    	* mangle.c (write_type): Strip cv-quals from FUNCTION_TYPE here.
    	(write_CV_qualifiers_for_type): Not here.

Patch

diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 0297a2a..c46ba30 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -1880,16 +1880,25 @@  write_type (tree type)
 	      break;
 
 	    case POINTER_TYPE:
-	      write_char ('P');
-	      write_type (TREE_TYPE (type));
-	      break;
-
 	    case REFERENCE_TYPE:
-	      if (TYPE_REF_IS_RVALUE (type))
-        	write_char('O');
+	      if (TREE_CODE (type) == POINTER_TYPE)
+		write_char ('P');
+	      else if (TYPE_REF_IS_RVALUE (type))
+		write_char ('O');
               else
                 write_char ('R');
-	      write_type (TREE_TYPE (type));
+	      {
+		tree target = TREE_TYPE (type);
+		/* Attribute const/noreturn are not reflected in mangling.
+		   We strip them here rather than at a lower level because
+		   a typedef or template argument can have function type
+		   with function-cv-quals (that use the same representation),
+		   but you can't have a pointer/reference to such a type.  */
+		if (abi_version_at_least (5)
+		    && TREE_CODE (target) == FUNCTION_TYPE)
+		  target = build_qualified_type (target, TYPE_UNQUALIFIED);
+		write_type (target);
+	      }
 	      break;
 
 	    case TEMPLATE_TYPE_PARM:
@@ -2017,12 +2026,6 @@  write_CV_qualifiers_for_type (const tree type)
      array.  */
   cp_cv_quals quals = TYPE_QUALS (type);
 
-  /* Attribute const/noreturn are not reflected in mangling.  */
-  if (abi_version_at_least (5)
-      && (TREE_CODE (type) == FUNCTION_TYPE
-	  || TREE_CODE (type) == METHOD_TYPE))
-    return 0;
-
   if (quals & TYPE_QUAL_RESTRICT)
     {
       write_char ('r');
diff --git a/gcc/testsuite/g++.dg/abi/mangle46.C b/gcc/testsuite/g++.dg/abi/mangle46.C
new file mode 100644
index 0000000..fddc88d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/mangle46.C
@@ -0,0 +1,15 @@ 
+// PR c++/48008
+// { dg-options -fabi-version=5 }
+// Test that we retain function-cv-quals in template argument mangling.
+
+template <class T>
+struct A
+{ };
+
+typedef void cfn(int) const;
+typedef void fn(int);
+
+// { dg-final { scan-assembler  "_Z1f1AIFviEE" } }
+void f(A<fn>) { }
+// { dg-final { scan-assembler  "_Z1f1AIKFviEE" } }
+void f(A<cfn>) { }