re PR c/83448 (ice in get_source_location_for_substring, at input.c:1507)

	PR c/83448
	* gimple-ssa-sprintf.c (maybe_warn): Don't call set_caret_index
	if navail is >= dir.len.

	* gcc.c-torture/compile/pr83448.c: New test.
	* gcc.dg/tree-ssa/builtin-snprintf-warn-4.c: New test.

From-SVN: r255960

gcc/ChangeLog

+2017-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/83448
+	* gimple-ssa-sprintf.c (maybe_warn): Don't call set_caret_index
+	if navail is >= dir.len.
+
 2017-12-21  Steve Ellcey  <sellcey@cavium.com>
 
 	* config/aarch64/t-aarch64-linux (MULTILIB_OSDIRNAMES): Fix

gcc/gimple-ssa-sprintf.c

@@ -2466,7 +2466,8 @@ maybe_warn (substring_loc &dirloc, location_t argloc,
 	  /* For plain character directives (i.e., the format string itself)
 	     but not others, point the caret at the first character that's
 	     past the end of the destination.  */
-	  dirloc.set_caret_index (dirloc.get_caret_idx () + navail);
+	  if (navail < dir.len)
+	    dirloc.set_caret_index (dirloc.get_caret_idx () + navail);
 	}
 
       if (*dir.beg == '\0')
@@ -2594,7 +2595,8 @@ maybe_warn (substring_loc &dirloc, location_t argloc,
       /* For plain character directives (i.e., the format string itself)
 	 but not others, point the caret at the first character that's
 	 past the end of the destination.  */
-      dirloc.set_caret_index (dirloc.get_caret_idx () + navail);
+      if (navail < dir.len)
+	dirloc.set_caret_index (dirloc.get_caret_idx () + navail);
     }
 
   if (*dir.beg == '\0')

gcc/testsuite/ChangeLog

+2017-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/83448
+	* gcc.c-torture/compile/pr83448.c: New test.
+	* gcc.dg/tree-ssa/builtin-snprintf-warn-4.c: New test.
+
 2017-12-21  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/atomic9.adb: New test.

gcc/testsuite/gcc.c-torture/compile/pr83448.c

+/* PR c/83448 */
+
+char *a;
+int b;
+
+void
+foo (void)
+{
+  for (;;)
+    {
+      if (b < 0)
+	foo ();
+      __builtin_snprintf (a, b, "%*s", b, "");
+    }
+}

gcc/testsuite/gcc.dg/tree-ssa/builtin-snprintf-warn-4.c

+/* PR c/83448 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wformat-truncation -fdiagnostics-show-caret" } */
+
+extern int snprintf (char *, __SIZE_TYPE__, const char *, ...);
+
+void
+foo (char *a, char *b, char *c, int d, int e)
+{
+  snprintf (a, 7, "abc\\\123 efg");
+  /* { dg-warning "directive output truncated writing 9 bytes into a region of size 7" "" { target *-*-* } .-1 }
+     { dg-message ".snprintf. output 10 bytes into a destination of size 7" "note" { target *-*-* } .-2 }
+     { dg-begin-multiline-output "" }
+   snprintf (a, 7, "abc\\\123 efg");
+                    ~~~~~~~~~~~^~
+     { dg-end-multiline-output "" }
+     { dg-begin-multiline-output "note" }
+   snprintf (a, 7, "abc\\\123 efg");
+   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+     { dg-end-multiline-output "" } */
+  d &= 63;
+  d += 10;
+  snprintf (b, 7, "a%dbcdefg", d);
+  /* { dg-warning "'bcdefg' directive output truncated writing 6 bytes into a region of size 4" "" { target *-*-* } .-1 }
+     { dg-message ".snprintf. output 10 bytes into a destination of size 7" "note" { target *-*-* } .-2 }
+     { dg-begin-multiline-output "" }
+   snprintf (b, 7, "a%dbcdefg", d);
+                       ~~~~^~
+     { dg-end-multiline-output "" }
+     { dg-begin-multiline-output "note" }
+   snprintf (b, 7, "a%dbcdefg", d);
+   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+     { dg-end-multiline-output "" } */
+  e &= 127;
+  snprintf (c, 7, "a%dbcdefgh", e);
+  /* { dg-warning "'bcdefgh' directive output truncated writing 7 bytes into a region of size between 3 and 5" "" { target *-*-* } .-1 }
+     { dg-message ".snprintf. output between 10 and 12 bytes into a destination of size 7" "note" { target *-*-* } .-2 }
+     { dg-begin-multiline-output "" }
+   snprintf (c, 7, "a%dbcdefgh", e);
+                       ~~~~~^~
+     { dg-end-multiline-output "" }
+     { dg-begin-multiline-output "note" }
+   snprintf (c, 7, "a%dbcdefgh", e);
+   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+     { dg-end-multiline-output "" } */
+}