On Wed, 29 Jan 2014, Richard Biener wrote:
>
> This removes the code that tries to avoid ICEs in the middle-end when
> facing calls through an incompatible type. The middle-end can now
> happily deal with those mismatches (and we rely on that). Also the
> code only detects the most primitive cases like
>
> ((bar_get_x_func*) foo_get_x) (x)
>
> but does not touch
>
> bar_get_x_func* fn = foo_get_x;
> fn (x);
>
> I preserved the warning (so I didn't have to remove the cast-function-1.c
> testcase) and fixed the testcase to be not optimized to nothing by the
> very first DCE pass and thus get non-empty assembler output with
> some calls and some inlines (yes, we _can_ inline some mismatches,
> esp. those refered to in the PR which is about void * vs some
> struct * type).
>
> Bootstrap / regtest running on x86_64-unknown-linux-gnu - ok for trunk?
testing reveals diagnostic regressions
FAIL: gcc.dg/call-diag-2.c abort (test for warnings, line 12)
FAIL: gcc.dg/call-diag-2.c abort (test for warnings, line 15)
FAIL: gcc.dg/invalid-call-1.c (test for warnings, line 16)
which may be hard to preserve (didn't investigate thoroughly yet),
one is probably emitted via the call to require_complete_type
I remove.
Is it ok to adjust the testcases expectation for what is produced now?
Otherwise I'll dump this patch for now.
Thanks,
Richard.
> Thanks,
> Richard.
>
> 2014-01-29 Richard Biener <rguent...@suse.de>
>
> PR c/59905
> * c-typeck.c (build_function_call_vec): Do not replace calls
> to a function via an incompatible type with a runtime abort.
>
> * gcc.dg/cast-function-1.c: Adjust to survive DCE.
>
> Index: gcc/c/c-typeck.c
> ===================================================================
> *** gcc/c/c-typeck.c (revision 207194)
> --- gcc/c/c-typeck.c (working copy)
> *************** build_function_call_vec (location_t loc,
> *** 2907,2962 ****
> return error_mark_node;
>
> /* Check that the function is called through a compatible prototype.
> ! If it is not, replace the call by a trap, wrapped up in a compound
> ! expression if necessary. This has the nice side-effect to prevent
> ! the tree-inliner from generating invalid assignment trees which may
> ! blow up in the RTL expander later. */
> if (CONVERT_EXPR_P (function)
> && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
> && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
> && !comptypes (fntype, TREE_TYPE (tem)))
> {
> tree return_type = TREE_TYPE (fntype);
> - tree trap = build_function_call (loc,
> - builtin_decl_explicit (BUILT_IN_TRAP),
> - NULL_TREE);
> - int i;
>
> /* This situation leads to run-time undefined behavior. We can't,
> therefore, simply error unless we can prove that all possible
> executions of the program must execute the code. */
> ! if (warning_at (loc, 0, "function called through a non-compatible
> type"))
> ! /* We can, however, treat "undefined" any way we please.
> ! Call abort to encourage the user to fix the program. */
> ! inform (loc, "if this code is reached, the program will abort");
> ! /* Before the abort, allow the function arguments to exit or
> ! call longjmp. */
> ! for (i = 0; i < nargs; i++)
> ! trap = build2 (COMPOUND_EXPR, void_type_node, (*params)[i], trap);
>
> ! if (VOID_TYPE_P (return_type))
> ! {
> ! if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
> ! pedwarn (loc, 0,
> ! "function with qualified void return type called");
> ! return trap;
> ! }
> ! else
> ! {
> ! tree rhs;
> !
> ! if (AGGREGATE_TYPE_P (return_type))
> ! rhs = build_compound_literal (loc, return_type,
> ! build_constructor (return_type,
> ! NULL),
> ! false);
> ! else
> ! rhs = build_zero_cst (return_type);
> !
> ! return require_complete_type (build2 (COMPOUND_EXPR, return_type,
> ! trap, rhs));
> ! }
> ! }
>
> argarray = vec_safe_address (params);
>
> --- 2907,2930 ----
> return error_mark_node;
>
> /* Check that the function is called through a compatible prototype.
> ! If it is not, warn. */
> if (CONVERT_EXPR_P (function)
> && TREE_CODE (tem = TREE_OPERAND (function, 0)) == ADDR_EXPR
> && TREE_CODE (tem = TREE_OPERAND (tem, 0)) == FUNCTION_DECL
> && !comptypes (fntype, TREE_TYPE (tem)))
> {
> tree return_type = TREE_TYPE (fntype);
>
> /* This situation leads to run-time undefined behavior. We can't,
> therefore, simply error unless we can prove that all possible
> executions of the program must execute the code. */
> ! warning_at (loc, 0, "function called through a non-compatible type");
>
> ! if (VOID_TYPE_P (return_type)
> ! && TYPE_QUALS (return_type) != TYPE_UNQUALIFIED)
> ! pedwarn (loc, 0,
> ! "function with qualified void return type called");
> ! }
>
> argarray = vec_safe_address (params);
>
> Index: gcc/testsuite/gcc.dg/cast-function-1.c
> ===================================================================
> *** gcc/testsuite/gcc.dg/cast-function-1.c (revision 207194)
> --- gcc/testsuite/gcc.dg/cast-function-1.c (working copy)
> *************** typedef struct {
> *** 16,27 ****
> int a;
> } str_t;
>
> ! void bar(void)
> {
> - double d;
> - int i;
> - str_t s;
> -
> d = ((double (*) (int)) foo1) (i); /* { dg-warning
> "33:non-compatible|abort" } */
> i = ((int (*) (double)) foo1) (d); /* { dg-warning
> "33:non-compatible|abort" } */
> s = ((str_t (*) (int)) foo1) (i); /* { dg-warning
> "32:non-compatible|abort" } */
> --- 16,23 ----
> int a;
> } str_t;
>
> ! void bar(double d, int i, str_t s)
> {
> d = ((double (*) (int)) foo1) (i); /* { dg-warning
> "33:non-compatible|abort" } */
> i = ((int (*) (double)) foo1) (d); /* { dg-warning
> "33:non-compatible|abort" } */
> s = ((str_t (*) (int)) foo1) (i); /* { dg-warning
> "32:non-compatible|abort" } */
> *************** void bar(void)
> *** 39,49 ****
> --- 35,49 ----
>
> int foo1(int arg)
> {
> + /* Prevent the function from becoming const and thus DCEd. */
> + __asm volatile ("" : "+r" (arg));
> return arg;
> }
>
> int foo2(arg)
> int arg;
> {
> + /* Prevent the function from becoming const and thus DCEd. */
> + __asm volatile ("" : "+r" (arg));
> return arg;
> }
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend"orffer
