[PATCH] Fix valgrind reported issue with diagnostics caret (PR c/69627)

[PATCH] Fix valgrind reported issue with diagnostics caret (PR c/69627)

[Jakub Jelinek]

Hi!

As range->m_caret.m_{line,column} is only initialized if
range->m_show_caret_p is true, we really shouldn't be looking at those
fields otherwise.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2016-02-03  Jakub Jelinek  <jakub@redhat.com>

	PR c/69627
	* diagnostic-show-locus.c (layout::get_state_at_point): Don't read
	range->m_caret fields if range->m_show_caret_p is false.

	* gcc.dg/pr69627.c: New test.

--- gcc/diagnostic-show-locus.c.jj	2016-01-26 20:50:26.000000000 +0100
+++ gcc/diagnostic-show-locus.c	2016-02-03 14:12:30.472706582 +0100
@@ -722,9 +722,10 @@ layout::get_state_at_point (/* Inputs.
 
 	  /* Are we at the range's caret?  is it visible? */
 	  out_state->draw_caret_p = false;
-	  if (row == range->m_caret.m_line
+	  if (range->m_show_caret_p
+	      && row == range->m_caret.m_line
 	      && column == range->m_caret.m_column)
-	    out_state->draw_caret_p = range->m_show_caret_p;
+	    out_state->draw_caret_p = true;
 
 	  /* Within a multiline range, don't display any underline
 	     in any leading or trailing whitespace on a line.
--- gcc/testsuite/gcc.dg/pr69627.c.jj	2016-02-03 14:21:17.063450583 +0100
+++ gcc/testsuite/gcc.dg/pr69627.c	2016-02-03 14:28:31.765465915 +0100
@@ -0,0 +1,27 @@
+/* PR c/69627 */
+/* { dg-do compile } */
+/* { dg-options "-fdiagnostics-show-caret" } */
+
+void
+foo ()
+{
+  float t[2] = { 1, 2 };
+  int const *s = 0;
+  t[1] / s;	/* { dg-error "invalid operands to binary /" } */
+/* { dg-begin-multiline-output "" }
+   t[1] / s;
+   ~~~~ ^
+   { dg-end-multiline-output "" } */
+}
+
+void
+bar ()
+{
+  float t[2] = { 1, 2 };
+  int const *s[2] = { 0, 0 };
+  t[1] / s[0];	/* { dg-error "invalid operands to binary /" } */
+/* { dg-begin-multiline-output "" }
+   t[1] / s[0];
+   ~~~~ ^ ~~~~
+   { dg-end-multiline-output "" } */
+}

	Jakub

Re: [PATCH] Fix valgrind reported issue with diagnostics caret (PR c/69627)

[David Malcolm]

On Wed, 2016-02-03 at 21:07 +0100, Jakub Jelinek wrote:
> Hi!
> 
> As range->m_caret.m_{line,column} is only initialized if
> range->m_show_caret_p is true, we really shouldn't be looking at
> those
> fields otherwise.
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for
> trunk?

I'm not a reviewer, but fwiw the change looks good to me; thanks.

[the uninitialized data is coming from:
gcc_rich_location::add_expr, which leaves m_show_caret_p as false, and
doesn't bother initializing m_caret].

Re: [PATCH] Fix valgrind reported issue with diagnostics caret (PR c/69627)

[Jeff Law]

On 02/03/2016 01:25 PM, David Malcolm wrote:
> On Wed, 2016-02-03 at 21:07 +0100, Jakub Jelinek wrote:
>> Hi!
>>
>> As range->m_caret.m_{line,column} is only initialized if
>> range->m_show_caret_p is true, we really shouldn't be looking at
>> those
>> fields otherwise.
>> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
>> ok for
>> trunk?
>
> I'm not a reviewer, but fwiw the change looks good to me; thanks.
>
> [the uninitialized data is coming from:
> gcc_rich_location::add_expr, which leaves m_show_caret_p as false, and
> doesn't bother initializing m_caret].
Given you know this code better than anyone, that should carry enough 
weight to be an approval, even if we haven't gone through the formal 
process of appointing you as a reviewer for these bits.

jeff
>