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
This commit is contained in:
Richard Guenther
Richard Biener
parent
0f8de04340
commit
8d2b04104d
7 changed files with 96 additions and 124 deletions
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@ -1,3 +1,19 @@
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2011-08-11 Richard Guenther <rguenther@suse.de>
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PR middle-end/50040
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* gimplify.c (gimplify_modify_expr_complex_part): Mark the
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load of the other piece with TREE_NO_WARNING.
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* tree-flow.h (warn_uninit): Adjust prototype.
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* tree-ssa.c (warn_uninit): Take uninitialized SSA name,
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the base variable and the expression that is used separately.
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Properly query all TREE_NO_WARNING flags.
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(struct walk_data): Remove.
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(warn_uninitialized_var): Likewise.
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(warn_uninitialized_vars): Do not walk gimple pieces but simply
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look at all SSA uses of the statement. Handle unused memory
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separately.
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* tree-ssa-uninit.c (warn_uninitialized_phi): Adjust.
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2011-08-11 Kazuhiro Inaoka <kazuhiro.inaoka.ud@renesas.com>
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* config/rx/rx.md (movsicc): Allow register to register
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@ -4483,6 +4483,7 @@ gimplify_modify_expr_complex_part (tree *expr_p, gimple_seq *pre_p,
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ocode = code == REALPART_EXPR ? IMAGPART_EXPR : REALPART_EXPR;
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other = build1 (ocode, TREE_TYPE (rhs), lhs);
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TREE_NO_WARNING (other) = 1;
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other = get_formal_tmp_var (other, pre_p);
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realpart = code == REALPART_EXPR ? rhs : other;
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@ -4,7 +4,7 @@
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struct a { int mode; };
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int sys_msgctl (void)
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{
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struct a setbuf; /* { dg-warning "'setbuf.mode' is used" "" { xfail *-*-* } } */
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return setbuf.mode;
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struct a setbuf;
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return setbuf.mode; /* { dg-warning "'setbuf.a::mode' is used" "" } */
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}
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@ -3,6 +3,6 @@
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int sys_msgctl (void)
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{
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struct { int mode; } setbuf; /* { dg-warning "'setbuf\.mode' is used" "" { xfail *-*-* } } */
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return setbuf.mode;
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struct { int mode; } setbuf;
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return setbuf.mode; /* { dg-warning "'setbuf\.mode' is used" "" } */
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}
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@ -542,7 +542,7 @@ extern void flush_pending_stmts (edge);
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extern void verify_ssa (bool);
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extern void delete_tree_ssa (void);
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extern bool ssa_undefined_value_p (tree);
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extern void warn_uninit (enum opt_code, tree, const char *, void *);
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extern void warn_uninit (enum opt_code, tree, tree, tree, const char *, void *);
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extern unsigned int warn_uninitialized_vars (bool);
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extern void execute_update_addresses_taken (void);
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@ -1953,7 +1953,8 @@ warn_uninitialized_phi (gimple phi, VEC(gimple, heap) **worklist,
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return;
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uninit_op = gimple_phi_arg_def (phi, MASK_FIRST_SET_BIT (uninit_opnds));
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warn_uninit (OPT_Wmaybe_uninitialized, uninit_op,
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warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, SSA_NAME_VAR (uninit_op),
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SSA_NAME_VAR (uninit_op),
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"%qD may be used uninitialized in this function",
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uninit_use_stmt);
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190
gcc/tree-ssa.c
190
gcc/tree-ssa.c
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@ -1652,14 +1652,15 @@ walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data,
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again for plain uninitialized variables, since optimization may have
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changed conditionally uninitialized to unconditionally uninitialized. */
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/* Emit a warning for T, an SSA_NAME, being uninitialized. The exact
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/* Emit a warning for EXPR based on variable VAR at the point in the
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program T, an SSA_NAME, is used being uninitialized. The exact
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warning text is in MSGID and LOCUS may contain a location or be null.
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WC is the warning code. */
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void
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warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
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warn_uninit (enum opt_code wc, tree t,
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tree expr, tree var, const char *gmsgid, void *data)
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{
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tree var = SSA_NAME_VAR (t);
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gimple context = (gimple) data;
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location_t location;
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expanded_location xloc, floc;
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@ -1669,11 +1670,11 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
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/* TREE_NO_WARNING either means we already warned, or the front end
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wishes to suppress the warning. */
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if (TREE_NO_WARNING (var))
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return;
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/* Do not warn if it can be initialized outside this module. */
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if (is_global_var (var))
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if ((context
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&& (gimple_no_warning_p (context)
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|| (gimple_assign_single_p (context)
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&& TREE_NO_WARNING (gimple_assign_rhs1 (context)))))
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|| TREE_NO_WARNING (expr))
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return;
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location = (context != NULL && gimple_has_location (context))
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@ -1681,9 +1682,9 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
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: DECL_SOURCE_LOCATION (var);
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xloc = expand_location (location);
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floc = expand_location (DECL_SOURCE_LOCATION (cfun->decl));
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if (warning_at (location, wc, gmsgid, var))
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if (warning_at (location, wc, gmsgid, expr))
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{
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TREE_NO_WARNING (var) = 1;
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TREE_NO_WARNING (expr) = 1;
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if (location == DECL_SOURCE_LOCATION (var))
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return;
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@ -1694,126 +1695,79 @@ warn_uninit (enum opt_code wc, tree t, const char *gmsgid, void *data)
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}
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}
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struct walk_data {
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gimple stmt;
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bool always_executed;
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bool warn_possibly_uninitialized;
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};
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/* Called via walk_tree, look for SSA_NAMEs that have empty definitions
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and warn about them. */
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static tree
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warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_)
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{
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struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
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struct walk_data *data = (struct walk_data *) wi->info;
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tree t = *tp;
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/* We do not care about LHS. */
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if (wi->is_lhs)
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{
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/* Except for operands of dereferences. */
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if (!INDIRECT_REF_P (t)
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&& TREE_CODE (t) != MEM_REF)
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return NULL_TREE;
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t = TREE_OPERAND (t, 0);
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}
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switch (TREE_CODE (t))
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{
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case ADDR_EXPR:
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/* Taking the address of an uninitialized variable does not
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count as using it. */
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*walk_subtrees = 0;
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break;
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case VAR_DECL:
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{
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/* A VAR_DECL in the RHS of a gimple statement may mean that
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this variable is loaded from memory. */
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use_operand_p vuse;
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tree op;
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/* If there is not gimple stmt,
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or alias information has not been computed,
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then we cannot check VUSE ops. */
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if (data->stmt == NULL)
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return NULL_TREE;
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/* If the load happens as part of a call do not warn about it. */
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if (is_gimple_call (data->stmt))
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return NULL_TREE;
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vuse = gimple_vuse_op (data->stmt);
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if (vuse == NULL_USE_OPERAND_P)
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return NULL_TREE;
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op = USE_FROM_PTR (vuse);
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if (t != SSA_NAME_VAR (op)
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|| !SSA_NAME_IS_DEFAULT_DEF (op))
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return NULL_TREE;
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/* If this is a VUSE of t and it is the default definition,
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then warn about op. */
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t = op;
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/* Fall through into SSA_NAME. */
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}
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case SSA_NAME:
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/* We only do data flow with SSA_NAMEs, so that's all we
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can warn about. */
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if (data->always_executed)
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warn_uninit (OPT_Wuninitialized,
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t, "%qD is used uninitialized in this function",
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data->stmt);
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else if (data->warn_possibly_uninitialized)
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warn_uninit (OPT_Wuninitialized,
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t, "%qD may be used uninitialized in this function",
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data->stmt);
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*walk_subtrees = 0;
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break;
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case REALPART_EXPR:
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case IMAGPART_EXPR:
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/* The total store transformation performed during gimplification
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creates uninitialized variable uses. If all is well, these will
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be optimized away, so don't warn now. */
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if (TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME)
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*walk_subtrees = 0;
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break;
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default:
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if (IS_TYPE_OR_DECL_P (t))
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*walk_subtrees = 0;
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break;
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}
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return NULL_TREE;
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}
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unsigned int
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warn_uninitialized_vars (bool warn_possibly_uninitialized)
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{
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gimple_stmt_iterator gsi;
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basic_block bb;
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struct walk_data data;
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data.warn_possibly_uninitialized = warn_possibly_uninitialized;
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FOR_EACH_BB (bb)
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{
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data.always_executed = dominated_by_p (CDI_POST_DOMINATORS,
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bool always_executed = dominated_by_p (CDI_POST_DOMINATORS,
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single_succ (ENTRY_BLOCK_PTR), bb);
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for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
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{
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struct walk_stmt_info wi;
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data.stmt = gsi_stmt (gsi);
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if (is_gimple_debug (data.stmt))
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gimple stmt = gsi_stmt (gsi);
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use_operand_p use_p;
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ssa_op_iter op_iter;
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tree use;
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if (is_gimple_debug (stmt))
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continue;
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memset (&wi, 0, sizeof (wi));
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wi.info = &data;
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walk_gimple_op (gsi_stmt (gsi), warn_uninitialized_var, &wi);
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/* We only do data flow with SSA_NAMEs, so that's all we
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can warn about. */
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FOR_EACH_SSA_USE_OPERAND (use_p, stmt, op_iter, SSA_OP_USE)
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{
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use = USE_FROM_PTR (use_p);
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if (always_executed)
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warn_uninit (OPT_Wuninitialized, use,
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SSA_NAME_VAR (use), SSA_NAME_VAR (use),
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"%qD is used uninitialized in this function",
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stmt);
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else if (warn_possibly_uninitialized)
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warn_uninit (OPT_Wuninitialized, use,
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SSA_NAME_VAR (use), SSA_NAME_VAR (use),
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"%qD may be used uninitialized in this function",
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stmt);
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}
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/* For memory the only cheap thing we can do is see if we
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have a use of the default def of the virtual operand.
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??? Note that at -O0 we do not have virtual operands.
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??? Not so cheap would be to use the alias oracle via
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walk_aliased_vdefs, if we don't find any aliasing vdef
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warn as is-used-uninitialized, if we don't find an aliasing
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vdef that kills our use (stmt_kills_ref_p), warn as
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may-be-used-uninitialized. But this walk is quadratic and
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so must be limited which means we would miss warning
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opportunities. */
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use = gimple_vuse (stmt);
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if (use
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&& gimple_assign_single_p (stmt)
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&& !gimple_vdef (stmt)
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&& SSA_NAME_IS_DEFAULT_DEF (use))
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{
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tree rhs = gimple_assign_rhs1 (stmt);
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tree base = get_base_address (rhs);
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/* Do not warn if it can be initialized outside this function. */
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if (TREE_CODE (base) != VAR_DECL
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|| DECL_HARD_REGISTER (base)
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|| is_global_var (base))
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continue;
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if (always_executed)
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warn_uninit (OPT_Wuninitialized, use, gimple_assign_rhs1 (stmt),
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base,
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"%qE is used uninitialized in this function",
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stmt);
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else if (warn_possibly_uninitialized)
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warn_uninit (OPT_Wuninitialized, use, gimple_assign_rhs1 (stmt),
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base,
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"%qE may be used uninitialized in this function",
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stmt);
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}
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}
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}
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