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analyzer: fix tests for UNKNOWN_LOCATION

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In the reproducer for PR analyzer/58237 I noticed that some events were
missing locations (and text); for example event 3 here:

    |   15 |   while (fgets(buf, 10, fp) != NULL)
    |      |         ~
    |      |         |
    |      |         (2) following 'false' branch...
    |
  'f1': event 3
    |
    |cc1:
    |
  'f1': event 4
    |
    |<source>:19:1:
    |   19 | }
    |      | ^
    |      | |
    |      | (4) 'fp' leaks here; was opened at (1)
    |

The root cause is that various places in the analyzer compare locations
against UNKNOWN_LOCATION, which fails to detect an unknown location for
the case where an unknown_location has been wrapped into an ad-hoc
location to record a block.

This patch fixes the issue by using get_pure_location whenever testing
against UNKNOWN_LOCATION to look through ad-hoc wrappers.

For the case above, it thus picks a better location in
supernode::get_start_location for event (3) above, improving it to:

    |   15 |   while (fgets(buf, 10, fp) != NULL)
    |      |         ~
    |      |         |
    |      |         (2) following 'false' branch...
    |......
    |   19 | }
    |      | ~
    |      | |
    |      | (3) ...to here
    |      | (4) 'fp' leaks here; was opened at (1)
    |

gcc/analyzer/ChangeLog:
	PR analyzer/58237
	* engine.cc (leak_stmt_finder::find_stmt): Use get_pure_location
	when comparing against UNKNOWN_LOCATION.
	(stmt_requires_new_enode_p): Likewise.
	(exploded_graph::dump_exploded_nodes): Likewise.
	* supergraph.cc (supernode::get_start_location): Likewise.
	(supernode::get_end_location): Likewise.

gcc/testsuite/ChangeLog:
	PR analyzer/58237
	* gcc.dg/analyzer/file-paths-1.c: New test.
This commit is contained in:
David Malcolm 2019-12-20 10:56:28 -05:00
parent 03dc3f2623
commit 8397af8ed0
5 changed files with 50 additions and 8 deletions
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10
gcc/analyzer/ChangeLog
View File

@ -1,3 +1,13 @@
2020-01-14 David Malcolm <dmalcolm@redhat.com>
PR analyzer/58237
* engine.cc (leak_stmt_finder::find_stmt): Use get_pure_location
when comparing against UNKNOWN_LOCATION.
(stmt_requires_new_enode_p): Likewise.
(exploded_graph::dump_exploded_nodes): Likewise.
* supergraph.cc (supernode::get_start_location): Likewise.
(supernode::get_end_location): Likewise.
2020-01-14 David Malcolm <dmalcolm@redhat.com>
PR analyzer/58237

8
gcc/analyzer/engine.cc
View File

@ -417,7 +417,7 @@ public:
const program_point &dst_point = dst_node->get_point ();
const gimple *stmt = dst_point.get_stmt ();
if (stmt)
if (stmt->location != UNKNOWN_LOCATION)
if (get_pure_location (stmt->location) != UNKNOWN_LOCATION)
return stmt;
}
@ -2300,8 +2300,8 @@ stmt_requires_new_enode_p (const gimple *stmt,
could be consolidated into PREV_STMT, giving us an event with
no location. Ensure that STMT gets its own exploded_node to
avoid this. */
if (prev_stmt->location == UNKNOWN_LOCATION
&& stmt->location != UNKNOWN_LOCATION)
if (get_pure_location (prev_stmt->location) == UNKNOWN_LOCATION
&& get_pure_location (stmt->location) != UNKNOWN_LOCATION)
return true;
return false;
@ -3098,7 +3098,7 @@ exploded_graph::dump_exploded_nodes () const
{
if (const gimple *stmt = enode->get_stmt ())
{
if (richloc.get_loc () == UNKNOWN_LOCATION)
if (get_pure_location (richloc.get_loc ()) == UNKNOWN_LOCATION)
richloc.set_range (0, stmt->location, SHOW_RANGE_WITH_CARET);
else
richloc.add_range (stmt->location,

10
gcc/analyzer/supergraph.cc
View File

@ -531,13 +531,14 @@ supernode::dump_dot_id (pretty_printer *pp) const
location_t
supernode::get_start_location () const
{
if (m_returning_call && m_returning_call->location != UNKNOWN_LOCATION)
if (m_returning_call
&& get_pure_location (m_returning_call->location) != UNKNOWN_LOCATION)
return m_returning_call->location;
int i;
gimple *stmt;
FOR_EACH_VEC_ELT (m_stmts, i, stmt)
if (stmt->location != UNKNOWN_LOCATION)
if (get_pure_location (stmt->location) != UNKNOWN_LOCATION)
return stmt->location;
if (entry_p ())
@ -561,10 +562,11 @@ supernode::get_end_location () const
int i;
gimple *stmt;
FOR_EACH_VEC_ELT_REVERSE (m_stmts, i, stmt)
if (stmt->location != UNKNOWN_LOCATION)
if (get_pure_location (stmt->location) != UNKNOWN_LOCATION)
return stmt->location;
if (m_returning_call && m_returning_call->location != UNKNOWN_LOCATION)
if (m_returning_call
&& get_pure_location (m_returning_call->location) != UNKNOWN_LOCATION)
return m_returning_call->location;
if (entry_p ())

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2020-01-14 David Malcolm <dmalcolm@redhat.com>
PR analyzer/58237
* gcc.dg/analyzer/file-paths-1.c: New test.
2020-01-14 David Malcolm <dmalcolm@redhat.com>
PR analyzer/58237

25
gcc/testsuite/gcc.dg/analyzer/file-paths-1.c Normal file
View File

@ -0,0 +1,25 @@
#include <stdio.h>
/* Verify that we correctly emit CFG events in the face of buffers
being clobbered in these leak reports. */
void f1 (const char *str)
{
FILE * fp = fopen(str, "r"); /* { dg-message "opened here" } */
char buf[10];
while (fgets(buf, 10, fp) != NULL) /* { dg-message "following 'false' branch\\.\\.\\." } */
{
}
} /* { dg-warning "leak of FILE 'fp'" } */
/* { dg-message "\\.\\.\\.to here" "" { target *-*-* } .-1 } */
void f2(const char *str, int flag)
{
FILE * fp = fopen(str, "r"); /* { dg-message "opened here" } */
char buf[10];
if (flag) /* { dg-message "when 'flag == 0'" } */
fclose(fp);
} /* { dg-warning "leak of FILE 'fp'" } */
/* { dg-message "\\.\\.\\.to here" "" { target *-*-* } .-1 } */