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re PR sanitizer/81275 (-fsanitize=thread produce incorrect -Wreturn-type warning)

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PR sanitizer/81275
	* tree.c (block_may_fallthru): Return false if SWITCH_ALL_CASES_P
	is set on SWITCH_EXPR and !block_may_fallthru (SWITCH_BODY ()).
c/
	* c-typeck.c (c_finish_case): Set SWITCH_ALL_CASES_P if
	c_switch_covers_all_cases_p returns true.
c-family/
	* c-common.c (c_switch_covers_all_cases_p_1,
	c_switch_covers_all_cases_p): New functions.
	* c-common.h (c_switch_covers_all_cases_p): Declare.
testsuite/
	* c-c++-common/tsan/pr81275.c: New test.

From-SVN: r255217
This commit is contained in:
Jakub Jelinek 2017-11-28 22:22:52 +01:00 committed by Jakub Jelinek
parent 67c24a8bd6
commit 058f0b9e5f
10 changed files with 206 additions and 0 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2017-11-28 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/81275
* tree.c (block_may_fallthru): Return false if SWITCH_ALL_CASES_P
is set on SWITCH_EXPR and !block_may_fallthru (SWITCH_BODY ()).
2017-11-28 Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>
Martin Jambor <mjambor@suse.cz>

7
gcc/c-family/ChangeLog
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@ -1,3 +1,10 @@
2017-11-28 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/81275
* c-common.c (c_switch_covers_all_cases_p_1,
c_switch_covers_all_cases_p): New functions.
* c-common.h (c_switch_covers_all_cases_p): Declare.
2017-11-28 Julia Koval <julia.koval@intel.com>
Sebastian Peryt <sebastian.peryt@intel.com>

58
gcc/c-family/c-common.c
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@ -4898,6 +4898,64 @@ c_add_case_label (location_t loc, splay_tree cases, tree cond, tree orig_type,
return error_mark_node;
}
/* Subroutine of c_switch_covers_all_cases_p, called via
splay_tree_foreach. Return 1 if it doesn't cover all the cases.
ARGS[0] is initially NULL and after the first iteration is the
so far highest case label. ARGS[1] is the minimum of SWITCH_COND's
type. */
static int
c_switch_covers_all_cases_p_1 (splay_tree_node node, void *data)
{
tree label = (tree) node->value;
tree *args = (tree *) data;
/* If there is a default case, we shouldn't have called this. */
gcc_assert (CASE_LOW (label));
if (args[0] == NULL_TREE)
{
if (wi::to_widest (args[1]) < wi::to_widest (CASE_LOW (label)))
return 1;
}
else if (wi::add (wi::to_widest (args[0]), 1)
!= wi::to_widest (CASE_LOW (label)))
return 1;
if (CASE_HIGH (label))
args[0] = CASE_HIGH (label);
else
args[0] = CASE_LOW (label);
return 0;
}
/* Return true if switch with CASES and switch condition with type
covers all possible values in the case labels. */
bool
c_switch_covers_all_cases_p (splay_tree cases, tree type)
{
/* If there is default:, this is always the case. */
splay_tree_node default_node
= splay_tree_lookup (cases, (splay_tree_key) NULL);
if (default_node)
return true;
if (!INTEGRAL_TYPE_P (type))
return false;
tree args[2] = { NULL_TREE, TYPE_MIN_VALUE (type) };
if (splay_tree_foreach (cases, c_switch_covers_all_cases_p_1, args))
return false;
/* If there are no cases at all, or if the highest case label
is smaller than TYPE_MAX_VALUE, return false. */
if (args[0] == NULL_TREE
|| wi::to_widest (args[0]) < wi::to_widest (TYPE_MAX_VALUE (type)))
return false;
return true;
}
/* Finish an expression taking the address of LABEL (an
IDENTIFIER_NODE). Returns an expression for the address.

1
gcc/c-family/c-common.h
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@ -969,6 +969,7 @@ extern int case_compare (splay_tree_key, splay_tree_key);
extern tree c_add_case_label (location_t, splay_tree, tree, tree, tree, tree,
bool *);
extern bool c_switch_covers_all_cases_p (splay_tree, tree);
extern tree build_function_call (location_t, tree, tree);

6
gcc/c/ChangeLog
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@ -1,3 +1,9 @@
2017-11-28 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/81275
* c-typeck.c (c_finish_case): Set SWITCH_ALL_CASES_P if
c_switch_covers_all_cases_p returns true.
2017-11-28 Julia Koval <julia.koval@intel.com>
Sebastian Peryt <sebastian.peryt@intel.com>

2
gcc/c/c-typeck.c
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@ -10360,6 +10360,8 @@ c_finish_case (tree body, tree type)
type ? type : TREE_TYPE (cs->switch_expr),
SWITCH_COND (cs->switch_expr),
cs->bool_cond_p, cs->outside_range_p);
if (c_switch_covers_all_cases_p (cs->cases, TREE_TYPE (cs->switch_expr)))
SWITCH_ALL_CASES_P (cs->switch_expr) = 1;
/* Pop the stack. */
c_switch_stack = cs->next;

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2017-11-28 Jakub Jelinek <jakub@redhat.com>
PR sanitizer/81275
* c-c++-common/tsan/pr81275.c: New test.
2017-11-28 Janne Blomqvist <jb@gcc.gnu.org>
PR fortran/53796

111
gcc/testsuite/c-c++-common/tsan/pr81275.c Normal file
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@ -0,0 +1,111 @@
/* PR sanitizer/81275 */
/* { dg-do compile } */
/* { dg-options "-Wreturn-type -fsanitize=thread" } */
int
f1 (int a, int b)
{
switch (a)
{
case 0:
switch (b)
{
case 5:
return 6;
case 7:
return 8;
default:
return 0;
}
break;
default:
return 0;
}
} /* { dg-bogus "control reaches end of non-void function" } */
int
f2 (int a, int b)
{
switch (a)
{
case 0:
switch (b)
{
case 5:
return 6;
case 7:
return 8;
default:
return 0;
}
default:
return 0;
}
} /* { dg-bogus "control reaches end of non-void function" } */
int
f3 (int a, int b)
{
switch (a)
{
case 0:
switch (b)
{
case 5:
return 6;
case 7:
return 8;
case 8:
break;
default:
return 0;
}
break;
default:
return 0;
}
} /* { dg-warning "control reaches end of non-void function" } */
int
f4 (int a, int b)
{
switch (a)
{
case 0:
switch (b)
{
case 5:
return 6;
case 7:
return 8;
}
break;
default:
return 0;
}
} /* { dg-warning "control reaches end of non-void function" } */
int
f5 (int a, unsigned char b)
{
switch (a)
{
case 0:
switch (b)
{
case 0:
return 1;
case 3 ... 10:
return 2;
case 1 ... 2:
return 3;
case 126 ... (unsigned char) ~0:
return 4;
case 11 ... 125:
return 5;
}
break;
default:
return 0;
}
} /* { dg-bogus "control reaches end of non-void function" } */

6
gcc/tree.c
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@ -12348,6 +12348,12 @@ block_may_fallthru (const_tree block)
return false;
case SWITCH_EXPR:
/* If there is a default: label or case labels cover all possible
SWITCH_COND values, then the SWITCH_EXPR will transfer control
to some case label in all cases and all we care is whether the
SWITCH_BODY falls through. */
if (SWITCH_ALL_CASES_P (stmt))
return block_may_fallthru (SWITCH_BODY (stmt));
return true;
case COND_EXPR:

4
gcc/tree.h
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@ -1166,6 +1166,10 @@ extern void protected_set_expr_location (tree, location_t);
/* SWITCH_EXPR accessors. These give access to the condition and body. */
#define SWITCH_COND(NODE) TREE_OPERAND (SWITCH_EXPR_CHECK (NODE), 0)
#define SWITCH_BODY(NODE) TREE_OPERAND (SWITCH_EXPR_CHECK (NODE), 1)
/* True if there are case labels for all possible values of SWITCH_COND, either
because there is a default: case label or because the case label ranges cover
all values. */
#define SWITCH_ALL_CASES_P(NODE) (SWITCH_EXPR_CHECK (NODE)->base.private_flag)
/* CASE_LABEL_EXPR accessors. These give access to the high and low values
of a case label, respectively. */