Commit 8d2b0410 by Richard Guenther Committed by Richard Biener

re PR middle-end/50040 (missed warning: ‘x.y’ is used uninitialized in this function)

2011-08-11  Richard Guenther  <rguenther@suse.de>

	PR middle-end/50040
	* gimplify.c (gimplify_modify_expr_complex_part): Mark the
	load of the other piece with TREE_NO_WARNING.
	* tree-flow.h (warn_uninit): Adjust prototype.
	* tree-ssa.c (warn_uninit): Take uninitialized SSA name,
	the base variable and the expression that is used separately.
	Properly query all TREE_NO_WARNING flags.
	(struct walk_data): Remove.
	(warn_uninitialized_var): Likewise.
	(warn_uninitialized_vars): Do not walk gimple pieces but simply
	look at all SSA uses of the statement.  Handle unused memory
	separately.
	* tree-ssa-uninit.c (warn_uninitialized_phi): Adjust.

	* g++.dg/warn/unit-1.C: Un-XFAIL.
	* gcc.dg/uninit-I.c: Likewise.

From-SVN: r177667
parent 0f8de043
2011-08-11 Richard Guenther <rguenther@suse.de>
PR middle-end/50040
* gimplify.c (gimplify_modify_expr_complex_part): Mark the
load of the other piece with TREE_NO_WARNING.
* tree-flow.h (warn_uninit): Adjust prototype.
* tree-ssa.c (warn_uninit): Take uninitialized SSA name,
the base variable and the expression that is used separately.
Properly query all TREE_NO_WARNING flags.
(struct walk_data): Remove.
(warn_uninitialized_var): Likewise.
(warn_uninitialized_vars): Do not walk gimple pieces but simply
look at all SSA uses of the statement. Handle unused memory
separately.
* tree-ssa-uninit.c (warn_uninitialized_phi): Adjust.
2011-08-11 Kazuhiro Inaoka <kazuhiro.inaoka.ud@renesas.com> 2011-08-11 Kazuhiro Inaoka <kazuhiro.inaoka.ud@renesas.com>
* config/rx/rx.md (movsicc): Allow register to register * config/rx/rx.md (movsicc): Allow register to register
......
...@@ -4483,6 +4483,7 @@ gimplify_modify_expr_complex_part (tree *expr_p, gimple_seq *pre_p, ...@@ -4483,6 +4483,7 @@ gimplify_modify_expr_complex_part (tree *expr_p, gimple_seq *pre_p,
ocode = code == REALPART_EXPR ? IMAGPART_EXPR : REALPART_EXPR; ocode = code == REALPART_EXPR ? IMAGPART_EXPR : REALPART_EXPR;
other = build1 (ocode, TREE_TYPE (rhs), lhs); other = build1 (ocode, TREE_TYPE (rhs), lhs);
TREE_NO_WARNING (other) = 1;
other = get_formal_tmp_var (other, pre_p); other = get_formal_tmp_var (other, pre_p);
realpart = code == REALPART_EXPR ? rhs : other; realpart = code == REALPART_EXPR ? rhs : other;
......
...@@ -4,7 +4,7 @@ ...@@ -4,7 +4,7 @@
struct a { int mode; }; struct a { int mode; };
int sys_msgctl (void) int sys_msgctl (void)
{ {
struct a setbuf; /* { dg-warning "'setbuf.mode' is used" "" { xfail *-*-* } } */ struct a setbuf;
return setbuf.mode; return setbuf.mode; /* { dg-warning "'setbuf.a::mode' is used" "" } */
} }
...@@ -3,6 +3,6 @@ ...@@ -3,6 +3,6 @@
int sys_msgctl (void) int sys_msgctl (void)
{ {
struct { int mode; } setbuf; /* { dg-warning "'setbuf\.mode' is used" "" { xfail *-*-* } } */ struct { int mode; } setbuf;
return setbuf.mode; return setbuf.mode; /* { dg-warning "'setbuf\.mode' is used" "" } */
} }
...@@ -542,7 +542,7 @@ extern void flush_pending_stmts (edge); ...@@ -542,7 +542,7 @@ extern void flush_pending_stmts (edge);
extern void verify_ssa (bool); extern void verify_ssa (bool);
extern void delete_tree_ssa (void); extern void delete_tree_ssa (void);
extern bool ssa_undefined_value_p (tree); extern bool ssa_undefined_value_p (tree);
extern void warn_uninit (enum opt_code, tree, const char *, void *); extern void warn_uninit (enum opt_code, tree, tree, tree, const char *, void *);
extern unsigned int warn_uninitialized_vars (bool); extern unsigned int warn_uninitialized_vars (bool);
extern void execute_update_addresses_taken (void); extern void execute_update_addresses_taken (void);
......
...@@ -1953,7 +1953,8 @@ warn_uninitialized_phi (gimple phi, VEC(gimple, heap) **worklist, ...@@ -1953,7 +1953,8 @@ warn_uninitialized_phi (gimple phi, VEC(gimple, heap) **worklist,
return; return;
uninit_op = gimple_phi_arg_def (phi, MASK_FIRST_SET_BIT (uninit_opnds)); uninit_op = gimple_phi_arg_def (phi, MASK_FIRST_SET_BIT (uninit_opnds));
warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, SSA_NAME_VAR (uninit_op),
SSA_NAME_VAR (uninit_op),
"%qD may be used uninitialized in this function", "%qD may be used uninitialized in this function",
uninit_use_stmt); uninit_use_stmt);
......
...@@ -1652,14 +1652,15 @@ walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data, ...@@ -1652,14 +1652,15 @@ walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data,
again for plain uninitialized variables, since optimization may have again for plain uninitialized variables, since optimization may have
changed conditionally uninitialized to unconditionally uninitialized. */ changed conditionally uninitialized to unconditionally uninitialized. */
/* Emit a warning for T, an SSA_NAME, being uninitialized. The exact /* Emit a warning for EXPR based on variable VAR at the point in the
program T, an SSA_NAME, is used being uninitialized. The exact
warning text is in MSGID and LOCUS may contain a location or be null. warning text is in MSGID and LOCUS may contain a location or be null.
WC is the warning code. */ WC is the warning code. */
void void
warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data) warn_uninit (enum opt_code wc, tree t,
tree expr, tree var, const char *gmsgid, void *data)
{ {
tree var = SSA_NAME_VAR (t);
gimple context = (gimple) data; gimple context = (gimple) data;
location_t location; location_t location;
expanded_location xloc, floc; expanded_location xloc, floc;
...@@ -1669,11 +1670,11 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data) ...@@ -1669,11 +1670,11 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
/* TREE_NO_WARNING either means we already warned, or the front end /* TREE_NO_WARNING either means we already warned, or the front end
wishes to suppress the warning. */ wishes to suppress the warning. */
if (TREE_NO_WARNING (var)) if ((context
return; && (gimple_no_warning_p (context)
|| (gimple_assign_single_p (context)
/* Do not warn if it can be initialized outside this module. */ && TREE_NO_WARNING (gimple_assign_rhs1 (context)))))
if (is_global_var (var)) || TREE_NO_WARNING (expr))
return; return;
location = (context != NULL && gimple_has_location (context)) location = (context != NULL && gimple_has_location (context))
...@@ -1681,9 +1682,9 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data) ...@@ -1681,9 +1682,9 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
: DECL_SOURCE_LOCATION (var); : DECL_SOURCE_LOCATION (var);
xloc = expand_location (location); xloc = expand_location (location);
floc = expand_location (DECL_SOURCE_LOCATION (cfun->decl)); floc = expand_location (DECL_SOURCE_LOCATION (cfun->decl));
if (warning_at (location, wc, gmsgid, var)) if (warning_at (location, wc, gmsgid, expr))
{ {
TREE_NO_WARNING (var) = 1; TREE_NO_WARNING (expr) = 1;
if (location == DECL_SOURCE_LOCATION (var)) if (location == DECL_SOURCE_LOCATION (var))
return; return;
...@@ -1694,126 +1695,79 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data) ...@@ -1694,126 +1695,79 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
} }
} }
struct walk_data {
gimple stmt;
bool always_executed;
bool warn_possibly_uninitialized;
};
/* Called via walk_tree, look for SSA_NAMEs that have empty definitions
and warn about them. */
static tree
warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_)
{
struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
struct walk_data *data = (struct walk_data *) wi->info;
tree t = *tp;
/* We do not care about LHS. */
if (wi->is_lhs)
{
/* Except for operands of dereferences. */
if (!INDIRECT_REF_P (t)
&& TREE_CODE (t) != MEM_REF)
return NULL_TREE;
t = TREE_OPERAND (t, 0);
}
switch (TREE_CODE (t))
{
case ADDR_EXPR:
/* Taking the address of an uninitialized variable does not
count as using it. */
*walk_subtrees = 0;
break;
case VAR_DECL:
{
/* A VAR_DECL in the RHS of a gimple statement may mean that
this variable is loaded from memory. */
use_operand_p vuse;
tree op;
/* If there is not gimple stmt,
or alias information has not been computed,
then we cannot check VUSE ops. */
if (data->stmt == NULL)
return NULL_TREE;
/* If the load happens as part of a call do not warn about it. */
if (is_gimple_call (data->stmt))
return NULL_TREE;
vuse = gimple_vuse_op (data->stmt);
if (vuse == NULL_USE_OPERAND_P)
return NULL_TREE;
op = USE_FROM_PTR (vuse);
if (t != SSA_NAME_VAR (op)
|| !SSA_NAME_IS_DEFAULT_DEF (op))
return NULL_TREE;
/* If this is a VUSE of t and it is the default definition,
then warn about op. */
t = op;
/* Fall through into SSA_NAME. */
}
case SSA_NAME:
/* We only do data flow with SSA_NAMEs, so that's all we
can warn about. */
if (data->always_executed)
warn_uninit (OPT_Wuninitialized,
t, "%qD is used uninitialized in this function",
data->stmt);
else if (data->warn_possibly_uninitialized)
warn_uninit (OPT_Wuninitialized,
t, "%qD may be used uninitialized in this function",
data->stmt);
*walk_subtrees = 0;
break;
case REALPART_EXPR:
case IMAGPART_EXPR:
/* The total store transformation performed during gimplification
creates uninitialized variable uses. If all is well, these will
be optimized away, so don't warn now. */
if (TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME)
*walk_subtrees = 0;
break;
default:
if (IS_TYPE_OR_DECL_P (t))
*walk_subtrees = 0;
break;
}
return NULL_TREE;
}
unsigned int unsigned int
warn_uninitialized_vars (bool warn_possibly_uninitialized) warn_uninitialized_vars (bool warn_possibly_uninitialized)
{ {
gimple_stmt_iterator gsi; gimple_stmt_iterator gsi;
basic_block bb; basic_block bb;
struct walk_data data;
data.warn_possibly_uninitialized = warn_possibly_uninitialized;
FOR_EACH_BB (bb) FOR_EACH_BB (bb)
{ {
data.always_executed = dominated_by_p (CDI_POST_DOMINATORS, bool always_executed = dominated_by_p (CDI_POST_DOMINATORS,
single_succ (ENTRY_BLOCK_PTR), bb); single_succ (ENTRY_BLOCK_PTR), bb);
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{ {
struct walk_stmt_info wi; gimple stmt = gsi_stmt (gsi);
data.stmt = gsi_stmt (gsi); use_operand_p use_p;
if (is_gimple_debug (data.stmt)) ssa_op_iter op_iter;
tree use;
if (is_gimple_debug (stmt))
continue; continue;
memset (&wi, 0, sizeof (wi));
wi.info = &data; /* We only do data flow with SSA_NAMEs, so that's all we
walk_gimple_op (gsi_stmt (gsi), warn_uninitialized_var, &wi); can warn about. */
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, op_iter, SSA_OP_USE)
{
use = USE_FROM_PTR (use_p);
if (always_executed)
warn_uninit (OPT_Wuninitialized, use,
SSA_NAME_VAR (use), SSA_NAME_VAR (use),
"%qD is used uninitialized in this function",
stmt);
else if (warn_possibly_uninitialized)
warn_uninit (OPT_Wuninitialized, use,
SSA_NAME_VAR (use), SSA_NAME_VAR (use),
"%qD may be used uninitialized in this function",
stmt);
}
/* For memory the only cheap thing we can do is see if we
have a use of the default def of the virtual operand.
??? Note that at -O0 we do not have virtual operands.
??? Not so cheap would be to use the alias oracle via
walk_aliased_vdefs, if we don't find any aliasing vdef
warn as is-used-uninitialized, if we don't find an aliasing
vdef that kills our use (stmt_kills_ref_p), warn as
may-be-used-uninitialized. But this walk is quadratic and
so must be limited which means we would miss warning
opportunities. */
use = gimple_vuse (stmt);
if (use
&& gimple_assign_single_p (stmt)
&& !gimple_vdef (stmt)
&& SSA_NAME_IS_DEFAULT_DEF (use))
{
tree rhs = gimple_assign_rhs1 (stmt);
tree base = get_base_address (rhs);
/* Do not warn if it can be initialized outside this function. */
if (TREE_CODE (base) != VAR_DECL
|| DECL_HARD_REGISTER (base)
|| is_global_var (base))
continue;
if (always_executed)
warn_uninit (OPT_Wuninitialized, use, gimple_assign_rhs1 (stmt),
base,
"%qE is used uninitialized in this function",
stmt);
else if (warn_possibly_uninitialized)
warn_uninit (OPT_Wuninitialized, use, gimple_assign_rhs1 (stmt),
base,
"%qE may be used uninitialized in this function",
stmt);
}
} }
} }
......
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