Running various JIT testcases under valgrid showed this one-time leak:
8,464 (336 direct, 8,128 indirect) bytes in 1 blocks are definitely lost in
loss record 144 of 147
at 0x4A081D4: calloc (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
by 0x5DF4EA0: xcalloc (xmalloc.c:162)
by 0x5DB0D9C: pretty_printer::pretty_printer(char const*, int)
(pretty-print.c:777)
by 0x54DA67D: __static_initialization_and_destruction_0(int, int)
(tree-pretty-print.c:66)
by 0x54DA6AF: _GLOBAL__sub_I_tree_pretty_print.c (tree-pretty-print.c:3542)
by 0x309540F2D9: call_init.part.0 (dl-init.c:82)
by 0x309540F3C2: _dl_init (dl-init.c:34)
by 0x3095401229: ??? (in /usr/lib64/ld-2.18.so)
by 0x1: ???
by 0xFFEFFFFBE: ???
by 0xFFEFFFFDA: ???
tree-pretty-print.c:66 is:
static pretty_printer buffer;
pretty-print.c:777 is:
pretty_printer::pretty_printer (const char *p, int l)
: buffer (new (XCNEW (output_buffer)) output_buffer ()),
This is the ctor of "buffer" (the pretty_printer) running at startup
by the dynamic linker, allocating its "buffer" output_buffer field
and the pair of obstacks it contains.
[Arguably "buffer" is a poor name for a pretty_printer, and these
should be named "pp" or somesuch, though that seems like it should
be a separate patch, which I'll do as a followup].
However, this ctor gets rerun the first time that
maybe_init_pretty_print is called, reallocating the output_buffer and
its obstacks, leaking the old ones:
static void
maybe_init_pretty_print (FILE *file)
{
if (!initialized)
{
new (&buffer) pretty_printer ();
/* etc */
}
/* etc */
}
This is a one-time leak, so it's worth fixing mostly for the sake of
keeping the valgrind output clean.
Having objects with non-empty ctors/dtors in a statically-allocated
section feels like too much C++ to me: we can't rely on the order in
which they run, and in the past I've been bitten by runtimes that
didn't support them fully (where the compiler worked, but the
linker/startup code didn't).
Hence this patch fixes the leak by rewriting the global "buffer" to
be a pointer, allocating the pp on the heap, eliminating the
before-main static ctor/dtor pair.
gcc/ChangeLog:
PR jit/63854
* tree-pretty-print.c: Eliminate include of <new>.
(buffer): Convert this variable from a pretty_printer to a
pretty_printer *.
(initialized): Eliminate this variable in favor of the NULL-ness
of "buffer".
(print_generic_decl): Update for "buffer" becoming a pointer.
(print_generic_stmt): Likewise.
(print_generic_stmt_indented): Likewise.
(print_generic_expr): Likewise.
(maybe_init_pretty_print): Likewise, allocating "buffer" on the
heap and using its non-NULL-ness to ensure idempotency.
---
gcc/tree-pretty-print.c | 34 +++++++++++++++-------------------
1 file changed, 15 insertions(+), 19 deletions(-)
diff --git a/gcc/tree-pretty-print.c b/gcc/tree-pretty-print.c
index 53720de..ddd7521 100644
--- a/gcc/tree-pretty-print.c
+++ b/gcc/tree-pretty-print.c
@@ -48,8 +48,6 @@ along with GCC; see the file COPYING3. If not see
#include "wide-int-print.h"
#include "internal-fn.h"
-#include <new> // For placement-new.
-
/* Local functions, macros and variables. */
static const char *op_symbol (const_tree);
static void pretty_print_string (pretty_printer *, const char*);
@@ -63,8 +61,7 @@ static void do_niy (pretty_printer *, const_tree);
#define NIY do_niy (buffer, node)
-static pretty_printer buffer;
-static int initialized = 0;
+static pretty_printer *buffer;
/* Try to print something for an unknown tree code. */
@@ -135,8 +132,8 @@ void
print_generic_decl (FILE *file, tree decl, int flags)
{
maybe_init_pretty_print (file);
- print_declaration (&buffer, decl, 2, flags);
- pp_write_text_to_stream (&buffer);
+ print_declaration (buffer, decl, 2, flags);
+ pp_write_text_to_stream (buffer);
}
/* Print tree T, and its successors, on file FILE. FLAGS specifies details
@@ -146,8 +143,8 @@ void
print_generic_stmt (FILE *file, tree t, int flags)
{
maybe_init_pretty_print (file);
- dump_generic_node (&buffer, t, 0, flags, true);
- pp_newline_and_flush (&buffer);
+ dump_generic_node (buffer, t, 0, flags, true);
+ pp_newline_and_flush (buffer);
}
/* Print tree T, and its successors, on file FILE. FLAGS specifies details
@@ -162,9 +159,9 @@ print_generic_stmt_indented (FILE *file, tree t, int flags,
int indent)
maybe_init_pretty_print (file);
for (i = 0; i < indent; i++)
- pp_space (&buffer);
- dump_generic_node (&buffer, t, indent, flags, true);
- pp_newline_and_flush (&buffer);
+ pp_space (buffer);
+ dump_generic_node (buffer, t, indent, flags, true);
+ pp_newline_and_flush (buffer);
}
/* Print a single expression T on file FILE. FLAGS specifies details to show
@@ -174,8 +171,8 @@ void
print_generic_expr (FILE *file, tree t, int flags)
{
maybe_init_pretty_print (file);
- dump_generic_node (&buffer, t, 0, flags, false);
- pp_flush (&buffer);
+ dump_generic_node (buffer, t, 0, flags, false);
+ pp_flush (buffer);
}
/* Dump the name of a _DECL node and its DECL_UID if TDF_UID is set
@@ -3389,15 +3386,14 @@ pretty_print_string (pretty_printer *buffer, const char
*str)
static void
maybe_init_pretty_print (FILE *file)
{
- if (!initialized)
+ if (!buffer)
{
- new (&buffer) pretty_printer ();
- pp_needs_newline (&buffer) = true;
- pp_translate_identifiers (&buffer) = false;
- initialized = 1;
+ buffer = new pretty_printer ();
+ pp_needs_newline (buffer) = true;
+ pp_translate_identifiers (buffer) = false;
}
- buffer.buffer->stream = file;
+ buffer->buffer->stream = file;
}
static void
--
1.8.5.3
