gcov-profile: Fix -fcompare-debug with -fprofile-generate [PR100520]

PR gcov-profile/100520

gcc/ChangeLog:

	* coverage.c (coverage_compute_profile_id): Strip .gk when
	compare debug is used.
	* system.h (endswith): New function.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr100520.c: New test.

gcc/coverage.c

@@ -571,8 +571,11 @@ coverage_compute_profile_id (struct cgraph_node *n)
       if (!use_name_only && first_global_object_name)
 	chksum = coverage_checksum_string
 	  (chksum, first_global_object_name);
-      chksum = coverage_checksum_string
-	(chksum, aux_base_name);
+      char *base_name = xstrdup (aux_base_name);
+      if (endswith (base_name, ".gk"))
+	base_name[strlen (base_name) - 3] = '\0';
+      chksum = coverage_checksum_string (chksum, base_name);
+      free (base_name);
     }
 
   /* Non-negative integers are hopefully small enough to fit in all targets.

gcc/system.h

@@ -1305,4 +1305,17 @@ startswith (const char *str, const char *prefix)
   return strncmp (str, prefix, strlen (prefix)) == 0;
 }
 
+/* Return true if STR string ends with SUFFIX.  */
+
+static inline bool
+endswith (const char *str, const char *suffix)
+{
+  size_t str_len = strlen (str);
+  size_t suffix_len = strlen (suffix);
+  if (str_len < suffix_len)
+    return false;
+
+  return memcmp (str + str_len - suffix_len, suffix, suffix_len) == 0;
+}
+
 #endif /* ! GCC_SYSTEM_H */

gcc/testsuite/gcc.dg/pr100520.c

@@ -0,0 +1,5 @@
+/* PR gcov-profile/100520 */
+/* { dg-do compile } */
+/* { dg-options "-fcompare-debug -fprofile-generate" } */
+
+static int f() {}