[committed] Fix memory leak of pretty_printer prefixes
David Malcolm
dmalcolm@redhat.com
Thu Aug 2 20:11:00 GMT 2018
We were rather sloppy about handling the ownership of prefixes for
pretty_printer, and this lead to a memory leak for any time a
diagnostic_show_locus call emits multiple line spans.
This showed up in "make selftest-valgrind" as:
3,976 bytes in 28 blocks are definitely lost in loss record 632 of 669
at 0x4A0645D: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
by 0x1F08227: xmalloc (xmalloc.c:147)
by 0x1F083E6: xvasprintf (xvasprintf.c:58)
by 0x1E7EC7D: build_message_string(char const*, ...) (diagnostic.c:78)
by 0x1E7F438: diagnostic_get_location_text(diagnostic_context*, expanded_location) (diagnostic.c:328)
by 0x1E7FD54: default_diagnostic_start_span_fn(diagnostic_context*, expanded_location) (diagnostic.c:626)
by 0x1EB3508: selftest::test_diagnostic_context::start_span_cb(diagnostic_context*, expanded_location) (selftest-diagnostic.c:57)
by 0x1E89215: diagnostic_show_locus(diagnostic_context*, rich_location*, diagnostic_t) (diagnostic-show-locus.c:1992)
by 0x1E8ECAD: selftest::test_fixit_insert_containing_newline_2(selftest::line_table_case const&) (diagnostic-show-locus.c:3044)
by 0x1EB0606: selftest::for_each_line_table_case(void (*)(selftest::line_table_case const&)) (input.c:3525)
by 0x1E8F3F5: selftest::diagnostic_show_locus_c_tests() (diagnostic-show-locus.c:3164)
by 0x1E010BF: selftest::run_tests() (selftest-run-tests.c:88)
4,004 bytes in 28 blocks are definitely lost in loss record 633 of 669
at 0x4A0645D: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
by 0x1F08227: xmalloc (xmalloc.c:147)
by 0x1F083E6: xvasprintf (xvasprintf.c:58)
by 0x1E7EC7D: build_message_string(char const*, ...) (diagnostic.c:78)
by 0x1E7F438: diagnostic_get_location_text(diagnostic_context*, expanded_location) (diagnostic.c:328)
by 0x1E7FD54: default_diagnostic_start_span_fn(diagnostic_context*, expanded_location) (diagnostic.c:626)
by 0x1EB3508: selftest::test_diagnostic_context::start_span_cb(diagnostic_context*, expanded_location) (selftest-diagnostic.c:57)
by 0x1E89215: diagnostic_show_locus(diagnostic_context*, rich_location*, diagnostic_t) (diagnostic-show-locus.c:1992)
by 0x1E8B373: selftest::test_diagnostic_show_locus_fixit_lines(selftest::line_table_case const&) (diagnostic-show-locus.c:2500)
by 0x1EB0606: selftest::for_each_line_table_case(void (*)(selftest::line_table_case const&)) (input.c:3525)
by 0x1E8F3B9: selftest::diagnostic_show_locus_c_tests() (diagnostic-show-locus.c:3159)
by 0x1E010BF: selftest::run_tests() (selftest-run-tests.c:88)
This patch fixes the leaks by ensuring that the pretty_printer "owns"
the prefix if it's non-NULL, freeing it in the dtor and in pp_set_prefix.
Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu;
manually verified "make selftest-valgrind" output (one unrelated leak
remains).
Committed to trunk as r263275.
gcc/cp/ChangeLog:
* error.c (cxx_print_error_function): Duplicate "file" before
passing it to pp_set_prefix.
(cp_print_error_function): Use pp_take_prefix when saving the
existing prefix.
gcc/ChangeLog:
* diagnostic-show-locus.c (diagnostic_show_locus): Use
pp_take_prefix when saving the existing prefix.
* diagnostic.c (diagnostic_append_note): Likewise.
* langhooks.c (lhd_print_error_function): Likewise.
* pretty-print.c (pp_set_prefix): Drop the "const" from "prefix"
param's type. Free the existing prefix.
(pp_take_prefix): New function.
(pretty_printer::pretty_printer): Drop the prefix parameter.
Rename the length parameter to match the comment.
(pretty_printer::~pretty_printer): Free the prefix.
* pretty-print.h (pretty_printer::pretty_printer): Drop the prefix
parameter.
(struct pretty_printer): Drop the "const" from "prefix" field's
type and clarify memory management.
(pp_set_prefix): Drop the "const" from the 2nd param.
(pp_take_prefix): New decl.
---
gcc/cp/error.c | 9 +++++++--
gcc/diagnostic-show-locus.c | 2 +-
gcc/diagnostic.c | 3 +--
gcc/langhooks.c | 2 +-
gcc/pretty-print.c | 31 +++++++++++++++++++++++--------
gcc/pretty-print.h | 14 ++++++++------
6 files changed, 41 insertions(+), 20 deletions(-)
diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index a12fbc5..c49f4d7 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -3287,8 +3287,13 @@ void
cxx_print_error_function (diagnostic_context *context, const char *file,
diagnostic_info *diagnostic)
{
+ char *prefix;
+ if (file)
+ prefix = xstrdup (file);
+ else
+ prefix = NULL;
lhd_print_error_function (context, file, diagnostic);
- pp_set_prefix (context->printer, file);
+ pp_set_prefix (context->printer, prefix);
maybe_print_instantiation_context (context);
}
@@ -3316,7 +3321,7 @@ cp_print_error_function (diagnostic_context *context,
return;
if (diagnostic_last_function_changed (context, diagnostic))
{
- const char *old_prefix = context->printer->prefix;
+ char *old_prefix = pp_take_prefix (context->printer);
const char *file = LOCATION_FILE (diagnostic_location (diagnostic));
tree abstract_origin = diagnostic_abstract_origin (diagnostic);
char *new_prefix = (file && abstract_origin == NULL)
diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-locus.c
index f188ee9..cf9e5c2 100644
--- a/gcc/diagnostic-show-locus.c
+++ b/gcc/diagnostic-show-locus.c
@@ -1978,7 +1978,7 @@ diagnostic_show_locus (diagnostic_context * context,
context->last_location = loc;
- const char *saved_prefix = pp_get_prefix (context->printer);
+ char *saved_prefix = pp_take_prefix (context->printer);
pp_set_prefix (context->printer, NULL);
layout layout (context, richloc, diagnostic_kind);
diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
index e22c17b..c61e0c4 100644
--- a/gcc/diagnostic.c
+++ b/gcc/diagnostic.c
@@ -1063,7 +1063,6 @@ diagnostic_append_note (diagnostic_context *context,
{
diagnostic_info diagnostic;
va_list ap;
- const char *saved_prefix;
rich_location richloc (line_table, location);
va_start (ap, gmsgid);
@@ -1073,7 +1072,7 @@ diagnostic_append_note (diagnostic_context *context,
va_end (ap);
return;
}
- saved_prefix = pp_get_prefix (context->printer);
+ char *saved_prefix = pp_take_prefix (context->printer);
pp_set_prefix (context->printer,
diagnostic_build_prefix (context, &diagnostic));
pp_format (context->printer, &diagnostic.message);
diff --git a/gcc/langhooks.c b/gcc/langhooks.c
index c7b5cf9..4e6179f 100644
--- a/gcc/langhooks.c
+++ b/gcc/langhooks.c
@@ -369,7 +369,7 @@ lhd_print_error_function (diagnostic_context *context, const char *file,
{
if (diagnostic_last_function_changed (context, diagnostic))
{
- const char *old_prefix = context->printer->prefix;
+ char *old_prefix = pp_take_prefix (context->printer);
tree abstract_origin = diagnostic_abstract_origin (diagnostic);
char *new_prefix = (file && abstract_origin == NULL)
? file_name_as_prefix (context, file) : NULL;
diff --git a/gcc/pretty-print.c b/gcc/pretty-print.c
index dc7791a..736af8f 100644
--- a/gcc/pretty-print.c
+++ b/gcc/pretty-print.c
@@ -1482,23 +1482,38 @@ pp_clear_output_area (pretty_printer *pp)
pp_buffer (pp)->line_length = 0;
}
-/* Set PREFIX for PRETTY-PRINTER. */
+/* Set PREFIX for PRETTY-PRINTER, taking ownership of PREFIX, which
+ will eventually be free-ed. */
+
void
-pp_set_prefix (pretty_printer *pp, const char *prefix)
+pp_set_prefix (pretty_printer *pp, char *prefix)
{
+ free (pp->prefix);
pp->prefix = prefix;
pp_set_real_maximum_length (pp);
pp->emitted_prefix = false;
pp_indentation (pp) = 0;
}
+/* Take ownership of PP's prefix, setting it to NULL.
+ This allows clients to save, overide, and then restore an existing
+ prefix, without it being free-ed. */
+
+char *
+pp_take_prefix (pretty_printer *pp)
+{
+ char *result = pp->prefix;
+ pp->prefix = NULL;
+ return result;
+}
+
/* Free PRETTY-PRINTER's prefix, a previously malloc()'d string. */
void
pp_destroy_prefix (pretty_printer *pp)
{
if (pp->prefix != NULL)
{
- free (CONST_CAST (char *, pp->prefix));
+ free (pp->prefix);
pp->prefix = NULL;
}
}
@@ -1535,10 +1550,9 @@ pp_emit_prefix (pretty_printer *pp)
}
}
-/* Construct a PRETTY-PRINTER with PREFIX and of MAXIMUM_LENGTH
- characters per line. */
+/* Construct a PRETTY-PRINTER of MAXIMUM_LENGTH characters per line. */
-pretty_printer::pretty_printer (const char *p, int l)
+pretty_printer::pretty_printer (int maximum_length)
: buffer (new (XCNEW (output_buffer)) output_buffer ()),
prefix (),
padding (pp_none),
@@ -1552,10 +1566,10 @@ pretty_printer::pretty_printer (const char *p, int l)
translate_identifiers (true),
show_color ()
{
- pp_line_cutoff (this) = l;
+ pp_line_cutoff (this) = maximum_length;
/* By default, we emit prefixes once per message. */
pp_prefixing_rule (this) = DIAGNOSTICS_SHOW_PREFIX_ONCE;
- pp_set_prefix (this, p);
+ pp_set_prefix (this, NULL);
}
pretty_printer::~pretty_printer ()
@@ -1564,6 +1578,7 @@ pretty_printer::~pretty_printer ()
delete m_format_postprocessor;
buffer->~output_buffer ();
XDELETE (buffer);
+ free (prefix);
}
/* Append a string delimited by START and END to the output area of
diff --git a/gcc/pretty-print.h b/gcc/pretty-print.h
index 56abe03..0d67e30 100644
--- a/gcc/pretty-print.h
+++ b/gcc/pretty-print.h
@@ -215,17 +215,18 @@ class format_postprocessor
and add additional fields they need. */
struct pretty_printer
{
- // Default construct a pretty printer with specified prefix
- // and a maximum line length cut off limit.
- explicit pretty_printer (const char* = NULL, int = 0);
+ /* Default construct a pretty printer with specified
+ maximum line length cut off limit. */
+ explicit pretty_printer (int = 0);
virtual ~pretty_printer ();
/* Where we print external representation of ENTITY. */
output_buffer *buffer;
- /* The prefix for each new line. */
- const char *prefix;
+ /* The prefix for each new line. If non-NULL, this is "owned" by the
+ pretty_printer, and will eventually be free-ed. */
+ char *prefix;
/* Where to put whitespace around the entity being formatted. */
pp_padding padding;
@@ -338,7 +339,8 @@ pp_get_prefix (const pretty_printer *pp) { return pp->prefix; }
#define pp_buffer(PP) (PP)->buffer
extern void pp_set_line_maximum_length (pretty_printer *, int);
-extern void pp_set_prefix (pretty_printer *, const char *);
+extern void pp_set_prefix (pretty_printer *, char *);
+extern char *pp_take_prefix (pretty_printer *);
extern void pp_destroy_prefix (pretty_printer *);
extern int pp_remaining_character_count_for_line (pretty_printer *);
extern void pp_clear_output_area (pretty_printer *);
--
1.8.5.3
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