[PATCH v4] Fix ICE when mixing VLAs and statement expressions [PR91038]
Uecker, Martin
Martin.Uecker@med.uni-goettingen.de
Mon Nov 8 18:13:27 GMT 2021
Am Montag, den 08.11.2021, 12:13 -0500 schrieb Jason Merrill:
> On 11/7/21 01:40, Uecker, Martin wrote:
> > Am Mittwoch, den 03.11.2021, 10:18 -0400 schrieb Jason Merrill:
...
> >
> > Thank you! I made these changes and ran
> > bootstrap and tests again.
>
> Hmm, it doesn't look like you made the change to use the save_expr
> function instead of build1?
Oh, sorry. I wanted to change it and then forgot.
Now also with this change (changelog as before).
> > Ok for trunk?
> >
> >
> > Any idea how to fix returning structs with
> > VLA member from statement expressions?
>
> Testcase?
void foo(void)
{
({ int N = 3; struct { char x[N]; } x; x; });
}
The difference to the tests in this patch (which
also forgot to include in the last version) is that
the object of variable size is returned from the
statement expression and not a pointer to it.
This can not happen with arrays because they decay
to pointers.
Martin
> > Otherwise, I will add an error message to
> > the FE in another patch.
> >
> > Martin
> >
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 436df45df68..95083f95442 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -3306,7 +3306,19 @@ pointer_int_sum (location_t loc, enum tree_code resultcode,
TREE_TYPE (result_type)))
size_exp = integer_one_node;
else
- size_exp = size_in_bytes_loc (loc, TREE_TYPE (result_type));
+ {
+ size_exp = size_in_bytes_loc (loc, TREE_TYPE (result_type));
+ /* Wrap the pointer expression in a SAVE_EXPR to make sure it
+ is evaluated first when the size expression may depend
+ on it for VM types. */
+ if (TREE_SIDE_EFFECTS (size_exp)
+ && TREE_SIDE_EFFECTS (ptrop)
+ && variably_modified_type_p (TREE_TYPE (ptrop), NULL))
+ {
+ ptrop = save_expr (ptrop);
+ size_exp = build2 (COMPOUND_EXPR, TREE_TYPE (intop), ptrop, size_exp);
+ }
+ }
/* We are manipulating pointer values, so we don't need to warn
about relying on undefined signed overflow. We disable the
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index c2ab96e7e18..84f7dc3c248 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -2964,7 +2964,9 @@ gimplify_var_or_parm_decl (tree *expr_p)
declaration, for which we've already issued an error. It would
be really nice if the front end wouldn't leak these at all.
Currently the only known culprit is C++ destructors, as seen
- in g++.old-deja/g++.jason/binding.C. */
+ in g++.old-deja/g++.jason/binding.C.
+ Another possible culpit are size expressions for variably modified
+ types which are lost in the FE or not gimplified correctly. */
if (VAR_P (decl)
&& !DECL_SEEN_IN_BIND_EXPR_P (decl)
&& !TREE_STATIC (decl) && !DECL_EXTERNAL (decl)
@@ -3109,16 +3111,22 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
expression until we deal with any variable bounds, sizes, or
positions in order to deal with PLACEHOLDER_EXPRs.
- So we do this in three steps. First we deal with the annotations
- for any variables in the components, then we gimplify the base,
- then we gimplify any indices, from left to right. */
+ The base expression may contain a statement expression that
+ has declarations used in size expressions, so has to be
+ gimplified before gimplifying the size expressions.
+
+ So we do this in three steps. First we deal with variable
+ bounds, sizes, and positions, then we gimplify the base,
+ then we deal with the annotations for any variables in the
+ components and any indices, from left to right. */
+
for (i = expr_stack.length () - 1; i >= 0; i--)
{
tree t = expr_stack[i];
if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
{
- /* Gimplify the low bound and element type size and put them into
+ /* Deal with the low bound and element type size and put them into
the ARRAY_REF. If these values are set, they have already been
gimplified. */
if (TREE_OPERAND (t, 2) == NULL_TREE)
@@ -3127,18 +3135,8 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
if (!is_gimple_min_invariant (low))
{
TREE_OPERAND (t, 2) = low;
- tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p,
- post_p, is_gimple_reg,
- fb_rvalue);
- ret = MIN (ret, tret);
}
}
- else
- {
- tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p, post_p,
- is_gimple_reg, fb_rvalue);
- ret = MIN (ret, tret);
- }
if (TREE_OPERAND (t, 3) == NULL_TREE)
{
@@ -3155,18 +3153,8 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
elmt_size, factor);
TREE_OPERAND (t, 3) = elmt_size;
- tret = gimplify_expr (&TREE_OPERAND (t, 3), pre_p,
- post_p, is_gimple_reg,
- fb_rvalue);
- ret = MIN (ret, tret);
}
}
- else
- {
- tret = gimplify_expr (&TREE_OPERAND (t, 3), pre_p, post_p,
- is_gimple_reg, fb_rvalue);
- ret = MIN (ret, tret);
- }
}
else if (TREE_CODE (t) == COMPONENT_REF)
{
@@ -3186,18 +3174,8 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
offset, factor);
TREE_OPERAND (t, 2) = offset;
- tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p,
- post_p, is_gimple_reg,
- fb_rvalue);
- ret = MIN (ret, tret);
}
}
- else
- {
- tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p, post_p,
- is_gimple_reg, fb_rvalue);
- ret = MIN (ret, tret);
- }
}
}
@@ -3208,21 +3186,34 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
fallback | fb_lvalue);
ret = MIN (ret, tret);
- /* And finally, the indices and operands of ARRAY_REF. During this
- loop we also remove any useless conversions. */
+ /* Step 3: gimplify size expressions and the indices and operands of
+ ARRAY_REF. During this loop we also remove any useless conversions. */
+
for (; expr_stack.length () > 0; )
{
tree t = expr_stack.pop ();
if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
{
+ /* Gimplify the low bound and element type size. */
+ tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p, post_p,
+ is_gimple_reg, fb_rvalue);
+ ret = MIN (ret, tret);
+
+ tret = gimplify_expr (&TREE_OPERAND (t, 3), pre_p, post_p,
+ is_gimple_reg, fb_rvalue);
+ ret = MIN (ret, tret);
+
/* Gimplify the dimension. */
- if (!is_gimple_min_invariant (TREE_OPERAND (t, 1)))
- {
- tret = gimplify_expr (&TREE_OPERAND (t, 1), pre_p, post_p,
- is_gimple_val, fb_rvalue);
- ret = MIN (ret, tret);
- }
+ tret = gimplify_expr (&TREE_OPERAND (t, 1), pre_p, post_p,
+ is_gimple_val, fb_rvalue);
+ ret = MIN (ret, tret);
+ }
+ else if (TREE_CODE (t) == COMPONENT_REF)
+ {
+ tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p, post_p,
+ is_gimple_reg, fb_rvalue);
+ ret = MIN (ret, tret);
}
STRIP_USELESS_TYPE_CONVERSION (TREE_OPERAND (t, 0));
@@ -6927,6 +6918,8 @@ gimplify_target_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
{
if (!TYPE_SIZES_GIMPLIFIED (TREE_TYPE (temp)))
gimplify_type_sizes (TREE_TYPE (temp), pre_p);
+ /* FIXME: this is correct only when the size of the type does
+ not depend on expressions evaluated in init. */
gimplify_vla_decl (temp, pre_p);
}
else
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-3.c b/gcc/testsuite/gcc.dg/vla-stexp-3.c
new file mode 100644
index 00000000000..e663de1cd72
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-3.c
@@ -0,0 +1,11 @@
+/* PR91038 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+
+void bar(void)
+{
+ ({ int N = 2; int (*x)[9][N] = 0; x; })[1];
+ ({ int N = 2; int (*x)[9][N] = 0; x; })[0]; // should not ice
+}
+
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-4.c b/gcc/testsuite/gcc.dg/vla-stexp-4.c
new file mode 100644
index 00000000000..612b5a802fc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-4.c
@@ -0,0 +1,94 @@
+/* PR29970, PR91038 */
+/* { dg-do run } */
+/* { dg-options "-O0 -Wunused-variable" } */
+
+int foo3b(void) // should not return 0
+{
+ int n = 0;
+ return sizeof *({ n = 10; int x[n]; &x; });
+}
+
+int foo4(void) // should not ICE
+{
+ return (*({
+ int n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ x;
+ }))[12][1];
+}
+
+int foo5(void) // should return 1, returns 0
+{
+ int n = 0;
+ return (*({
+ n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }))[12][1];
+}
+
+int foo5c(void) // should return 400
+{
+ int n = 0;
+ return sizeof(*({
+ n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }));
+}
+
+int foo5b(void) // should return 1, returns 0
+{
+ int n = 0; /* { dg-warning "unused variable" } */
+ return (*({
+ int n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }))[12][1];
+}
+
+int foo5a(void) // should return 1, returns 0
+{
+ return (*({
+ int n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }))[12][1];
+}
+
+
+
+
+int main()
+{
+ if (sizeof(int[10]) != foo3b())
+ __builtin_abort();
+
+ if (1 != foo4())
+ __builtin_abort();
+
+ if (400 != foo5c())
+ __builtin_abort();
+
+ if (1 != foo5a())
+ __builtin_abort();
+
+ if (1 != foo5b()) // -O0
+ __builtin_abort();
+
+ if (1 != foo5())
+ __builtin_abort();
+
+ return 0;
+}
+
+
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-5.c b/gcc/testsuite/gcc.dg/vla-stexp-5.c
new file mode 100644
index 00000000000..d6a7f2b34b8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-5.c
@@ -0,0 +1,30 @@
+/* PR29970 */
+/* { dg-do run } */
+/* { dg-options "-Wunused-variable" } */
+
+
+
+
+int foo2a(void) // should not ICE
+{
+ return ({ int n = 20; struct { int x[n];} x; x.x[12] = 1; sizeof(x); });
+}
+
+
+int foo2b(void) // should not ICE
+{
+ return sizeof *({ int n = 20; struct { int x[n];} x; x.x[12] = 1; &x; });
+}
+
+int main()
+{
+ if (sizeof(struct { int x[20]; }) != foo2a())
+ __builtin_abort();
+
+ if (sizeof(struct { int x[20]; }) != foo2b())
+ __builtin_abort();
+
+ return 0;
+}
+
+
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-6.c b/gcc/testsuite/gcc.dg/vla-stexp-6.c
new file mode 100644
index 00000000000..3d96d38898b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-6.c
@@ -0,0 +1,94 @@
+/* PR29970, PR91038 */
+/* { dg-do run } */
+/* { dg-options "-O2 -Wunused-variable" } */
+
+int foo3b(void) // should not return 0
+{
+ int n = 0;
+ return sizeof *({ n = 10; int x[n]; &x; });
+}
+
+int foo4(void) // should not ICE
+{
+ return (*({
+ int n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ x;
+ }))[12][1];
+}
+
+int foo5(void) // should return 1, returns 0
+{
+ int n = 0;
+ return (*({
+ n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }))[12][1];
+}
+
+int foo5c(void) // should return 400
+{
+ int n = 0;
+ return sizeof(*({
+ n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }));
+}
+
+int foo5b(void) // should return 1, returns 0
+{
+ int n = 0; /* { dg-warning "unused variable" } */
+ return (*({
+ int n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }))[12][1];
+}
+
+int foo5a(void) // should return 1, returns 0
+{
+ return (*({
+ int n = 20;
+ char (*x)[n][n] = __builtin_malloc(n * n);
+ (*x)[12][1] = 1;
+ (*x)[0][1] = 0;
+ x;
+ }))[12][1];
+}
+
+
+
+
+int main()
+{
+ if (sizeof(int[10]) != foo3b())
+ __builtin_abort();
+
+ if (1 != foo4())
+ __builtin_abort();
+
+ if (400 != foo5c())
+ __builtin_abort();
+
+ if (1 != foo5a())
+ __builtin_abort();
+
+ if (1 != foo5b()) // -O0
+ __builtin_abort();
+
+ if (1 != foo5())
+ __builtin_abort();
+
+ return 0;
+}
+
+
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-7.c b/gcc/testsuite/gcc.dg/vla-stexp-7.c
new file mode 100644
index 00000000000..3091b9184c2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-7.c
@@ -0,0 +1,44 @@
+/* PR91038 */
+/* { dg-do run } */
+/* { dg-options "-O2 -Wunused-variable" } */
+
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+struct lbm {
+
+ int D;
+ const int* DQ;
+
+} D2Q9 = { 2,
+ (const int*)&(const int[9][2]){
+ { 0, 0 },
+ { 1, 0 }, { 0, 1 }, { -1, 0 }, { 0, -1 },
+ { 1, 1 }, { -1, 1 }, { -1, -1 }, { 1, -1 },
+ }
+};
+
+void zouhe_left(void)
+{
+ __auto_type xx = (*({ int N = 2; struct lbm __x = D2Q9; ((const int(*)[9][N])__x.DQ); }));
+
+ if (1 != xx[1][0])
+ __builtin_abort();
+
+ if (2 != ARRAY_SIZE(xx[1]))
+ __builtin_abort();
+
+ if (1 != (*({ int N = 2; struct lbm __x = D2Q9; ((const int(*)[9][N])__x.DQ); }))[1][0])
+ __builtin_abort();
+
+ if (2 != ARRAY_SIZE(*({ int N = 2; struct lbm __x = D2Q9; ((const int(*)[9][N])__x.DQ);
})[1]))
+ __builtin_abort();
+}
+
+int main()
+{
+ zouhe_left();
+ return 0;
+}
+
+
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-8.c b/gcc/testsuite/gcc.dg/vla-stexp-8.c
new file mode 100644
index 00000000000..5b475eb6cf2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-8.c
@@ -0,0 +1,47 @@
+/* PR29970, PR91038 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wunused-variable" } */
+
+
+int foo0(void)
+{
+ int c = *(*(*({ int n = 10; int (*x)[n][n] = __builtin_malloc(sizeof *x); x; }) + 5) + 5);
+ return c;
+}
+
+int foo1(void)
+{
+ int c = *(5 + *(5 + *({ int n = 10; int (*x)[n][n] = __builtin_malloc(sizeof *x); x; })));
+ return c;
+}
+
+int bar2(void)
+{
+ int c = (*({ int n = 10; struct { int y[n]; int z; }* x = __builtin_malloc(sizeof *x); x;
})).z;
+ return c;
+}
+
+int bar3(void)
+{
+ int n = 2; /* { dg-warning "unused variable" } */
+ int c = (*({ int n = 3; /* { dg-warning "unused variable" } */
+ ({ int n = 10; int (*x)[n][n] = __builtin_malloc(sizeof *x); x; }); }))[5][5];
+ return c;
+}
+
+int bar3b(void)
+{
+ int n = 2; /* { dg-warning "unused variable" } */
+ int c = (*({ int n = 3; /* { dg-warning "unused variable" } */
+ ({ int n = 10; int (*x)[n][n] = __builtin_malloc(sizeof *x); x; }); }))[0][0];
+ return c;
+}
+
+int bar4(void)
+{
+ int n = 2; /* { dg-warning "unused variable" } */
+ int c = *(5 + *( 5 + *({ int n = 3; /* { dg-warning "unused variable" } */
+ ({ int n = 10; int (*x)[n][n] = __builtin_malloc(sizeof *x); x; }); })));
+ return c;
+}
+
diff --git a/gcc/testsuite/gcc.dg/vla-stexp-9.c b/gcc/testsuite/gcc.dg/vla-stexp-9.c
new file mode 100644
index 00000000000..3593a790785
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vla-stexp-9.c
@@ -0,0 +1,53 @@
+/* PR91038 */
+/* { dg-do run } */
+/* { dg-options "-O2 -Wunused-variable" } */
+
+
+
+void foo(void)
+{
+ if (2 * sizeof(int) != sizeof((*({ int N = 2; int (*x)[9][N] = 0; x; })[1])))
+ __builtin_abort();
+}
+
+void bar(void)
+{
+ if (2 * sizeof(int) != sizeof((*({ int N = 2; int (*x)[9][N] = 0; x; })[0])))
+ __builtin_abort();
+}
+
+void bar0(void)
+{
+ if (2 * 9 * sizeof(int) != sizeof((*({ int N = 2; int (*x)[9][N] = 0; x; }))))
+ __builtin_abort();
+}
+
+void bar11(void)
+{
+ sizeof(*((*({ int N = 2; int (*x)[9][N] = 0; x; }) + 0)));
+}
+
+void bar12(void)
+{
+ if (2 * sizeof(int) != sizeof(*((*({ int N = 2; int (*x)[9][N] = 0; x; }) ))))
+ __builtin_abort();
+}
+
+void bar1(void)
+{
+ if (2 * sizeof(int) != sizeof(*((*({ int N = 2; int (*x)[9][N] = 0; x; }) + 0))))
+ __builtin_abort();
+}
+
+
+
+
+int main()
+{
+ foo();
+ bar0();
+ bar12();
+ bar1();
+ bar();
+}
+
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