PR c/94040 - ICE on a call to an invalid redeclaration of strftime

gcc/c/ChangeLog:

	PR c/94040
	* c-decl.c (builtin_structptr_type_count): New constant.
	(match_builtin_function_types): Reject decls that are incompatible
	in types pointed to by pointers.
	(diagnose_mismatched_decls): Adjust comments.

gcc/testsuite/ChangeLog:

	PR c/94040
	* gcc.dg/Wbuiltin-declaration-mismatch-12.c: Relax test to look
	for warning name rather than the exact text.
	* gcc.dg/Wbuiltin-declaration-mismatch-14.c: New test.
	* gcc.dg/Wbuiltin-declaration-mismatch-15.c: New test.
	* gcc.dg/pr62090.c: Prune expected warning.
	* gcc.dg/pr89314.c: Look for warning name rather than text.

6 files changed, 148 insertions, 3 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e7b8c88..a379b40 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2020-03-13  Martin Sebor  <msebor@redhat.com>
+
+	PR c/94040
+	* gcc.dg/Wbuiltin-declaration-mismatch-12.c: Relax test to look
+	for warning name rather than the exact text.
+	* gcc.dg/Wbuiltin-declaration-mismatch-14.c: New test.
+	* gcc.dg/Wbuiltin-declaration-mismatch-15.c: New test.
+	* gcc.dg/pr62090.c: Prune expected warning.
+	* gcc.dg/pr89314.c: Look for warning name rather than text.
+
 2020-03-13  Uroš Bizjak  <ubizjak@gmail.com>
 
 	* gcc.target/i386/pr64409.c: Do not limit compilation to x32 targets.
diff --git a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c
index 6bf9762..f12ef6a 100644
--- a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c
+++ b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-12.c
@@ -3,6 +3,6 @@
    { dg-do compile }
    { dg-options "-Wbuiltin-declaration-mismatch -Wextra" } */
 
-extern void __clear_cache (char*, char*);   /* { dg-warning "mismatch in argument 1 type of built-in function .__clear_cache.; expected .void \\\*." } */
+extern void __clear_cache (char*, char*);      // { dg-warning "\\\[-Wbuiltin-declaration-mismatch" }
 
-void __builtin_prefetch (const char *, ...);   /* { dg-warning "mismatch in argument 1 type of built-in function .__builtin_prefetch.; expected .const void \\\*." } */
+void __builtin_prefetch (const char *, ...);   // { dg-warning "\\\[-Wbuiltin-declaration-mismatch" }
diff --git a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-14.c b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-14.c
new file mode 100644
index 0000000..cc536d7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-14.c
@@ -0,0 +1,77 @@
+/* PR c/94040 - ICE on a call to an invalid redeclaration of strftime
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+typedef __SIZE_TYPE__ size_t;
+
+struct tm;
+
+size_t strftime (char *, size_t, int *, struct tm *);   // { dg-warning "-Wbuiltin-declaration-mismatch" }
+
+size_t call_strftime (char *d, size_t n, int *f, struct tm *t)
+{
+  size_t r = 0;
+  r += strftime (0, 0, 0, 0);
+  r += strftime (d, 0, 0, 0);
+  r += strftime (d, n, 0, 0);
+  r += strftime (d, n, f, 0);
+  r += strftime (d, n, f, t);
+  return r;
+}
+
+
+char* strchr (char*, char*); // { dg-warning "-Wbuiltin-declaration-mismatch" }
+
+// Verify that missing/extra qualifiers aren't diagnosed without -Wextra.
+
+int strcmp (char*, char*);
+int strncmp (volatile char*, volatile char*, size_t);
+
+// Verify that a difference in pointers is diagnosed.
+
+size_t strlen (const char**);
+// { dg-warning "-Wbuiltin-declaration-mismatch" "pointer" { target *-*-* } .-1 }
+
+ size_t strnlen (const char* const*, size_t);
+// { dg-warning "-Wbuiltin-declaration-mismatch" "pointer" { target *-*-* } .-1 }
+
+
+// Verify that calls to the compatibly-redeclared built-ins are treated
+// as those to the built-ins and diagnosed.
+
+int test_builtin_calls (size_t n)
+{
+  int r = 0;
+  r += strcmp ((char*)0, "");               // { dg-warning "\\\[-Wnonnull]" }
+  r += strcmp ("", (char*)0);               // { dg-warning "\\\[-Wnonnull]" }
+
+  r += strncmp ((char*)0, "", n);           // { dg-warning "\\\[-Wnonnull]" }
+  r += strncmp ("", (char*)0, n);           // { dg-warning "\\\[-Wnonnull]" }
+
+  return r;
+}
+
+
+// Verify that calls to the incompatibly-redeclared built-ins are not
+// treated as those to the built-ins by the middle-end.  It doesn't
+// matter if the front-end diagnoses them but the middle-end should
+// not because it shouldn't recognize them as built-ins.
+
+#pragma GCC optimize "2"
+
+size_t test_nonbuiltin_calls (char *s, int c)
+{
+  void *null = 0;
+
+  char *r;
+  r = strchr ((char*)null, s);
+  r = strchr (r, (char*)null);
+  *s = *r;   // use the result
+
+  size_t n = 0;
+  n += strftime (0, 0, 0, 0);
+  n += strlen ((const char**)null);
+  n += strnlen ((const char**)null, n);
+
+  return n;
+}
diff --git a/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-15.c b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-15.c
new file mode 100644
index 0000000..3c32a5f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wbuiltin-declaration-mismatch-15.c
@@ -0,0 +1,56 @@
+/* PR c/94040 - ICE on a call to an invalid redeclaration of strftime
+   { dg-do compile }
+   { dg-options "-Wall -Wextra" } */
+
+typedef __SIZE_TYPE__ size_t;
+
+struct tm;
+
+size_t strftime (const char *, size_t, char *, struct tm *);
+// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 1" { target *-*-* } .-1 }
+
+// Verify that missing/extra qualifiers are diagnosed with -Wextra.
+
+int strcmp (char*, const char*);
+// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 1" { target *-*-* } .-1 }
+
+int strncmp (const char*, volatile char*, size_t);
+// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 2" { target *-*-* } .-1 }
+
+size_t strlen (char*);
+// { dg-warning "-Wbuiltin-declaration-mismatch" "arg 1" { target *-*-* } .-1 }
+
+
+// Verify that calls to built-ins declared with missing/extra qualifiers
+// are still treated as those to built-ins by the front-end.
+
+int test_builtin_calls_fe (size_t n)
+{
+  int r = 0;
+  r += strcmp ((char*)0, "");               // { dg-warning "\\\[-Wnonnull]" }
+  r += strcmp ("", (char*)0);               // { dg-warning "\\\[-Wnonnull]" }
+
+  r += strncmp ((char*)0, "", n);           // { dg-warning "\\\[-Wnonnull]" }
+  r += strncmp ("", (char*)0, n);           // { dg-warning "\\\[-Wnonnull]" }
+
+  r += strlen ((char*)0);                   // { dg-warning "\\\[-Wnonnull]" }
+  return r;
+}
+
+
+// Ditto but by the middle-end.
+
+#pragma GCC optimize "2"
+
+int test_builtin_calls_me (void)
+{
+  char *null1 = 0;
+  char *null2 = null1;
+  char *null3 = null2;
+
+  int r = 0;
+  r += strcmp (null1, "123");               // { dg-warning "\\\[-Wnonnull]" }
+  r += strncmp ("2345", null2, 4);          // { dg-warning "\\\[-Wnonnull]" }
+  r += strlen (null3);                      // { dg-warning "\\\[-Wnonnull]" }
+  return r;
+}
diff --git a/gcc/testsuite/gcc.dg/pr62090.c b/gcc/testsuite/gcc.dg/pr62090.c
index 53089cf..42f1345 100644
--- a/gcc/testsuite/gcc.dg/pr62090.c
+++ b/gcc/testsuite/gcc.dg/pr62090.c
@@ -15,3 +15,5 @@ log_bad_request ()
 {
   b += sprintf (0, "foo");
 }
+
+/* { dg-prune-output "\\\[-Wbuiltin-declaration-mismatch]" } */
diff --git a/gcc/testsuite/gcc.dg/pr89314.c b/gcc/testsuite/gcc.dg/pr89314.c
index e35dd8c..27b3a51 100644
--- a/gcc/testsuite/gcc.dg/pr89314.c
+++ b/gcc/testsuite/gcc.dg/pr89314.c
@@ -2,7 +2,7 @@
 /* { dg-do compile } */
 /* { dg-options "-O2 -Wbuiltin-declaration-mismatch -Wextra" } */
 
-extern __SIZE_TYPE__ strlen (const float *);	/* { dg-warning "mismatch in argument 1 type of built-in function" } */
+extern __SIZE_TYPE__ strlen (const float *);	/* { dg-warning "\\\[-Wbuiltin-declaration-mismatch" } */
 void bar (void);
 
 void