On 15 January 2016 at 03:27, Joseph Myers <jos...@codesourcery.com> wrote: > On Thu, 14 Jan 2016, Prathamesh Kulkarni wrote: > >> Hi, >> For test-case containing only the following declaration: >> static struct undefined_struct object; >> gcc rejects it at -O0 in assemble_variable() with error "storage size >> of <var> is unknown", >> however no error is reported when compiled with -O2. > > Cf bug 24293 (for the -fsyntax-only case) - does this patch fix that? Ah this doesn't fix PR24293, it seems analyze_function() doesn't get called for -fsyntax-only. I don't have a good solution for this. I assume varpool won't be populated for -fsyntax-only ? And we need to walk over decls with incomplete struct/union types after parsing the whole translation unit. In the attached patch, I kept a global vec<tree> incomplete_record_decls; In finish_decl(), if the decl is static, has type struct/union and size 0 then it is appened to incomplete_record_decls. In c_parser_translation_unit(), iterate over incomplete_record_decls and if report error if any decl has size zero. The patch passes testsuite.
Thanks,
Prathamesh
>
>> g++ rejects it during parsing. I tried similarly in C FE by adding a
>> check for decl with incomplete struct/union type in finish_decl(),
>> however that fails to compile the following case:
>> typedef struct foo foo_t;
>> foo_t x;
>> struct foo { int i; };
>> g++ rejects the above case as well but gcc accepts it.
>> Do C and C++ standards differ in this regard ?
>
> I don't know about C++, but this sort of thing is valid C if the type is
> complete at the end of the translation unit or is an incomplete array type
> (but not in the case where the variable is static - such a case with
> static, if supported, is an extension).
>
> --
> Joseph S. Myers
> jos...@codesourcery.com
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 915376d..ac542e1 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -4791,6 +4791,12 @@ finish_decl (tree decl, location_t init_loc, tree init,
TREE_TYPE (decl) = error_mark_node;
}
+ if (RECORD_OR_UNION_TYPE_P (TREE_TYPE (decl))
+ && DECL_SIZE (decl) == 0 && TREE_STATIC (decl))
+ {
+ incomplete_record_decls.safe_push (decl);
+ }
+
if (is_global_var (decl) && DECL_SIZE (decl) != 0)
{
if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST)
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index a0e0052..8af04f7 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -59,6 +59,8 @@ along with GCC; see the file COPYING3. If not see
#include "gimple-expr.h"
#include "context.h"
+vec<tree> incomplete_record_decls = vNULL;
+
void
set_c_expr_source_range (c_expr *expr,
location_t start, location_t finish)
@@ -1421,6 +1423,13 @@ c_parser_translation_unit (c_parser *parser)
}
while (c_parser_next_token_is_not (parser, CPP_EOF));
}
+
+ for (unsigned i = 0; i < incomplete_record_decls.length (); ++i)
+ {
+ tree decl = incomplete_record_decls[i];
+ if (DECL_SIZE (decl) == 0)
+ error ("storage size of %q+D isn%'t known", decl);
+ }
}
/* Parse an external declaration (C90 6.7, C99 6.9).
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 81a3d58..cf79ba7 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -731,4 +731,6 @@ set_c_expr_source_range (c_expr *expr,
/* In c-fold.c */
extern tree decl_constant_value_for_optimization (tree);
+extern vec<tree> incomplete_record_decls;
+
#endif /* ! GCC_C_TREE_H */
diff --git a/gcc/testsuite/gcc.dg/Wcxx-compat-8.c
b/gcc/testsuite/gcc.dg/Wcxx-compat-8.c
index f7e8c55..4e9ddc1 100644
--- a/gcc/testsuite/gcc.dg/Wcxx-compat-8.c
+++ b/gcc/testsuite/gcc.dg/Wcxx-compat-8.c
@@ -33,6 +33,7 @@ enum e3
__typeof__ (struct s5 { int i; }) v5; /* { dg-warning "invalid in C\[+\]\[+\]"
} */
__typeof__ (struct t5) w5; /* { dg-bogus "invalid in C\[+\]\[+\]" } */
+ /* { dg-error "storage size of 'w5' isn't known" "" { target *-*-* } 35 } */
int
f1 (struct s1 *p)
@@ -64,4 +65,4 @@ f5 ()
return &((struct t8) { }); /* { dg-warning "invalid in C\[+\]\[+\]" } */
}
-/* { dg-error "invalid use of undefined type" "" { target *-*-* } 64 } */
+/* { dg-error "invalid use of undefined type" "" { target *-*-* } 65 } */
diff --git a/gcc/testsuite/gcc.dg/declspec-1.c
b/gcc/testsuite/gcc.dg/declspec-1.c
index c19f107..9113076 100644
--- a/gcc/testsuite/gcc.dg/declspec-1.c
+++ b/gcc/testsuite/gcc.dg/declspec-1.c
@@ -9,7 +9,8 @@ typedef int t;
/* These should all be diagnosed, but only once, not for every
identifier declared. */
struct s0 int x0, /* { dg-error "two or more data types" } */
-x1;
+/* { dg-error "storage size of 'x0' isn't known" "" { target *-*-* } 11 } */
+x1; /* { dg-error "storage size of 'x1' isn't known" } */
char union u0 x2, /* { dg-error "two or more data types" } */
x3;
diff --git a/gcc/testsuite/gcc.dg/pr24293.c b/gcc/testsuite/gcc.dg/pr24293.c
new file mode 100644
index 0000000..33285e7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr24293.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-fsyntax-only" } */
+
+static struct foo x; /* { dg-error "storage size of 'x' isn't known" } */
+static union bar y; /* { dg-error "storage size of 'y' isn't known" } */
+
+typedef struct P p;
+static p p_obj; /* { dg-error "storage size of 'p_obj' isn't known" } */
+
+extern struct undefined_object object;
ChangeLog
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