c: Try the type with the previous function attributes

When there are 2 conflicting function declarations, try the new type
with the previous TYPE_ATTRIBUTES if the current declaration has no
TYPE_ATTRIBUTES to support

extern void foo (void) __attribute__((nocf_check));

void
foo (void)
{
}

instead of issuing an error:

$ gcc -O2 -fcf-protection -S x.c
x.c:4:1: error: conflicting types for ‘foo’; have ‘void(void)’
    4 | foo (void)
      | ^~~
x.c:1:13: note: previous declaration of ‘foo’ with type ‘void(void)’
    1 | extern void foo (void) __attribute__((nocf_check));
      |             ^~~

The resulting function definition is compatible with the previous
declaration.

gcc/c/

	PR c/122427
	* c-decl.cc (diagnose_mismatched_decls): For FUNCTION_DECL, if
	OLDDECL has TYPE_ATTRIBUTES and NEWDECL doesn't, try the type
	with the OLDDECL attributes.

gcc/testsuite/

	PR c/122427
	* g++.target/i386/cf_check-1.C: New test.
	* g++.target/i386/cf_check-2.C: Likewise.
	* g++.target/i386/cf_check-3.C: Likewise.
	* g++.target/i386/cf_check-4.C: Likewise.
	* gcc.target/i386/cf_check-7.c: Likewise.
	* gcc.target/i386/cf_check-8.c: Likewise.
	* gcc.target/i386/cf_check-9.c: Likewise.
	* gcc.target/i386/cf_check-10.c: Likewise.
	* gcc.target/i386/cf_check-11.c: Likewise.
	* gcc.target/i386/no-callee-saved-12.c: Remove dg-error.
	* gcc.target/i386/preserve-none-17.c: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>

diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index 061892ac95b89ee642221af82bac6d213be615fc..2b31a4328f87787dd846dd78d63db63bdf19ef0b 100644 (file)
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -2337,10 +2337,40 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl,
                error ("conflicting type qualifiers for %q+D", newdecl);
            }
          else
-           error ("conflicting types for %q+D; have %qT", newdecl, newtype);
-         diagnose_arglist_conflict (newdecl, olddecl, newtype, oldtype);
-         locate_old_decl (olddecl);
-         return false;
+           {
+             if (TREE_CODE (olddecl) == FUNCTION_DECL)
+               {
+                 tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (olddecl));
+                 if (attrs && !TYPE_ATTRIBUTES (TREE_TYPE (newdecl)))
+                   {
+                     /* Similar to the C++ front-end, for FUNCTION_DECL,
+                        if OLDDECL has attributes and NEWDECL doesn't,
+                        try the type with OLDDECL attributes.  */
+                     tree rettype = TREE_TYPE (newtype);
+                     tree tryargs = TYPE_ARG_TYPES (newtype);
+                     tree trytype = c_build_function_type (rettype,
+                                                           tryargs);
+                     trytype = c_build_type_attribute_variant (trytype,
+                                                               attrs);
+                     if (comptypes (oldtype, trytype))
+                       {
+                         *newtypep = newtype = trytype;
+                         comptypes_result = 1;
+                       }
+                   }
+               }
+
+             if (!comptypes_result)
+               error ("conflicting types for %q+D; have %qT", newdecl,
+                      newtype);
+           }
+         if (!comptypes_result)
+           {
+             diagnose_arglist_conflict (newdecl, olddecl, newtype,
+                                        oldtype);
+             locate_old_decl (olddecl);
+             return false;
+           }
        }
     }
   /* Warn about enum/integer type mismatches.  They are compatible types

diff --git a/gcc/testsuite/g++.target/i386/cf_check-1.C b/gcc/testsuite/g++.target/i386/cf_check-1.C
new file mode 100644 (file)
index 0000000..59fcca6
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/cf_check-1.C
@@ -0,0 +1,18 @@
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+
+extern void foo (void) __attribute__((nocf_check));
+extern void foo (void);
+
+void
+foo (void)
+{
+}
+
+extern void bar (void);
+extern void bar (void) __attribute__((nocf_check)); /* { dg-error "ambiguating new declaration" } */
+
+void
+bar (void)
+{
+}

diff --git a/gcc/testsuite/g++.target/i386/cf_check-2.C b/gcc/testsuite/g++.target/i386/cf_check-2.C
new file mode 100644 (file)
index 0000000..5718ab2
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/cf_check-2.C
@@ -0,0 +1,14 @@
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+
+extern void bar (void);
+extern void bar (void) __attribute__((nocf_check)); /* { dg-error "ambiguating new declaration" } */
+extern void foo (void) __attribute__((nocf_check));
+extern void foo (void);
+
+void
+func (void)
+{
+  bar ();
+  foo ();
+}

diff --git a/gcc/testsuite/g++.target/i386/cf_check-3.C b/gcc/testsuite/g++.target/i386/cf_check-3.C
new file mode 100644 (file)
index 0000000..79d3a25
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/cf_check-3.C
@@ -0,0 +1,19 @@
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.} } } */
+
+/*
+**_Z3foov:
+**.LFB[0-9]+:
+**     .cfi_startproc
+**     ret
+**...
+*/
+
+extern void foo (void) __attribute__((nocf_check));
+
+void
+foo (void)
+{
+}

diff --git a/gcc/testsuite/g++.target/i386/cf_check-4.C b/gcc/testsuite/g++.target/i386/cf_check-4.C
new file mode 100644 (file)
index 0000000..57c40a5
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/cf_check-4.C
@@ -0,0 +1,23 @@
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-require-weak "" } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.} } } */
+
+/*
+**_Z3foov:
+**.LFB[0-9]+:
+**     .cfi_startproc
+**     ret
+**...
+*/
+
+extern void foo (void) __attribute__((nocf_check));
+
+__attribute__((weak))
+void
+foo (void)
+{
+}
+
+/* { dg-final { scan-assembler ".weak\[ \t\]_?_Z3foov" } } */

diff --git a/gcc/testsuite/gcc.target/i386/cf_check-10.c b/gcc/testsuite/gcc.target/i386/cf_check-10.c
new file mode 100644 (file)
index 0000000..a131672
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/cf_check-10.c
@@ -0,0 +1,19 @@
+/* PR c/122427 */
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+
+extern void foo (void) __attribute__((nocf_check));
+extern void foo (void);
+
+void
+foo (void)
+{
+}
+
+extern void bar (void);
+extern void bar (void) __attribute__((nocf_check)); /* { dg-error "conflicting types" } */
+
+void
+bar (void)
+{
+}

diff --git a/gcc/testsuite/gcc.target/i386/cf_check-11.c b/gcc/testsuite/gcc.target/i386/cf_check-11.c
new file mode 100644 (file)
index 0000000..9ed65ab
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/cf_check-11.c
@@ -0,0 +1,24 @@
+/* PR c/122427 */
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-require-weak "" } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+**     .cfi_startproc
+**     ret
+**...
+*/
+
+extern void foo (void) __attribute__((nocf_check));
+
+__attribute__((weak))
+void
+foo (void)
+{
+}
+
+/* { dg-final { scan-assembler ".weak\[ \t\]_?foo" } } */

diff --git a/gcc/testsuite/gcc.target/i386/cf_check-7.c b/gcc/testsuite/gcc.target/i386/cf_check-7.c
new file mode 100644 (file)
index 0000000..b9a3b39
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/cf_check-7.c
@@ -0,0 +1,20 @@
+/* PR c/122427 */
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+**     .cfi_startproc
+**     ret
+**...
+*/
+
+extern void foo (void) __attribute__((nocf_check));
+
+void
+foo (void)
+{
+}

diff --git a/gcc/testsuite/gcc.target/i386/cf_check-8.c b/gcc/testsuite/gcc.target/i386/cf_check-8.c
new file mode 100644 (file)
index 0000000..48e8cf1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/cf_check-8.c
@@ -0,0 +1,11 @@
+/* PR c/122427 */
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+
+extern void foo (void);
+
+__attribute__((nocf_check))
+void
+foo (void) /* { dg-error "conflicting types" } */
+{
+}

diff --git a/gcc/testsuite/gcc.target/i386/cf_check-9.c b/gcc/testsuite/gcc.target/i386/cf_check-9.c
new file mode 100644 (file)
index 0000000..057c60f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/cf_check-9.c
@@ -0,0 +1,15 @@
+/* PR c/122427 */
+/* { dg-do compile { target { "i?86-*-* x86_64-*-*" } } } */
+/* { dg-options "-O2 -fcf-protection" } */
+
+extern void bar (void);
+extern void bar (void) __attribute__((nocf_check)); /* { dg-error "conflicting types" } */
+extern void foo (void) __attribute__((nocf_check));
+extern void foo (void);
+
+void
+func (void)
+{
+  bar ();
+  foo ();
+}

diff --git a/gcc/testsuite/gcc.target/i386/no-callee-saved-12.c b/gcc/testsuite/gcc.target/i386/no-callee-saved-12.c
index 5524a4af29ce4e1d5dfecba051ea53aeb2f8ce63..8f9b725e911332309d5188d82252650b14b98559 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/no-callee-saved-12.c
+++ b/gcc/testsuite/gcc.target/i386/no-callee-saved-12.c
@@ -1,10 +1,9 @@
 /* { dg-do compile } */
 /* { dg-options "-O2" } */
 
-extern void foo (void) __attribute__ ((no_callee_saved_registers)); /* { dg-note "previous declaration" } */
+extern void foo (void) __attribute__ ((no_callee_saved_registers));
 
 void
-foo (void) /* { dg-error "conflicting types" } */
+foo (void)
 {
 }
-

diff --git a/gcc/testsuite/gcc.target/i386/preserve-none-17.c b/gcc/testsuite/gcc.target/i386/preserve-none-17.c
index e105da1b709575df4143417b8f4583583aa3d735..0c62edd0fd02d653bf77add4927c69a480714179 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/preserve-none-17.c
+++ b/gcc/testsuite/gcc.target/i386/preserve-none-17.c
@@ -1,10 +1,9 @@
 /* { dg-do compile } */
 /* { dg-options "-O2" } */
 
-extern void foo (void) __attribute__ ((preserve_none)); /* { dg-note "previous declaration" } */
+extern void foo (void) __attribute__ ((preserve_none));
 
 void
-foo (void) /* { dg-error "conflicting types" } */
+foo (void)
 {
 }
-