c: After issuing errors about array size, for error-recovery don't make the array VLA [PR93573]

Message ID 20200328005608.GW2156@tucnak
State New
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Series
  • c: After issuing errors about array size, for error-recovery don't make the array VLA [PR93573]
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Commit Message

Marek Polacek via Gcc-patches March 28, 2020, 12:56 a.m.
Hi!

After we report various errors about array size, we set for error-recovery
the size to be 1, but because size_int_const is false, it still means we
pretend the array is a VLA, can emit a second diagnostics in that case etc.
E.g.
$ ./cc1.unpatched -quiet a.c
a.c:1:5: error: size of array ‘f’ has non-integer type
    1 | int f[100.0];
      |     ^
a.c:1:1: warning: variably modified ‘f’ at file scope
    1 | int f[100.0];
      | ^~~
$ ./cc1 -quiet a.c
a.c:1:5: error: size of array ‘f’ has non-integer type
    1 | int f[100.0];
      |     ^

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2020-03-28  Jakub Jelinek  <jakub@redhat.com>

	PR c/93573
	* c-decl.c (grokdeclarator): After issuing errors, set size_int_const
	to true after setting size to integer_one_node.

	* gcc.dg/pr93573-1.c: New test.


	Jakub

Comments

Joseph Myers March 28, 2020, 12:58 a.m. | #1
On Sat, 28 Mar 2020, Jakub Jelinek via Gcc-patches wrote:

> Hi!

> 

> After we report various errors about array size, we set for error-recovery

> the size to be 1, but because size_int_const is false, it still means we

> pretend the array is a VLA, can emit a second diagnostics in that case etc.

> E.g.

> $ ./cc1.unpatched -quiet a.c

> a.c:1:5: error: size of array ‘f’ has non-integer type

>     1 | int f[100.0];

>       |     ^

> a.c:1:1: warning: variably modified ‘f’ at file scope

>     1 | int f[100.0];

>       | ^~~

> $ ./cc1 -quiet a.c

> a.c:1:5: error: size of array ‘f’ has non-integer type

>     1 | int f[100.0];

>       |     ^

> 

> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?


OK.

-- 
Joseph S. Myers
joseph@codesourcery.com

Patch

--- gcc/c/c-decl.c.jj	2020-03-19 22:55:50.107685767 +0100
+++ gcc/c/c-decl.c	2020-03-27 17:54:16.017024925 +0100
@@ -6416,6 +6416,7 @@  grokdeclarator (const struct c_declarato
 		      error_at (loc,
 				"size of unnamed array has non-integer type");
 		    size = integer_one_node;
+		    size_int_const = true;
 		  }
 		/* This can happen with enum forward declaration.  */
 		else if (!COMPLETE_TYPE_P (TREE_TYPE (size)))
@@ -6427,6 +6428,7 @@  grokdeclarator (const struct c_declarato
 		      error_at (loc, "size of unnamed array has incomplete "
 				"type");
 		    size = integer_one_node;
+		    size_int_const = true;
 		  }
 
 		size = c_fully_fold (size, false, &size_maybe_const);
@@ -6451,6 +6453,7 @@  grokdeclarator (const struct c_declarato
 			else
 			  error_at (loc, "size of unnamed array is negative");
 			size = integer_one_node;
+			size_int_const = true;
 		      }
 		    /* Handle a size folded to an integer constant but
 		       not an integer constant expression.  */
--- gcc/testsuite/gcc.dg/pr93573-1.c.jj	2020-03-27 17:55:39.085781301 +0100
+++ gcc/testsuite/gcc.dg/pr93573-1.c	2020-03-27 17:56:35.168941677 +0100
@@ -0,0 +1,12 @@ 
+/* PR c/93573 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+void bar ();
+
+void
+foo (char a)
+{
+  union C { int d[100.0]; char *e; };	/* { dg-error "has non-integer type" } */
+  bar ((union C) &a);
+}