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Re: [patch] PR symtab/13277: Resolving opaque structures in ICC generated binaries.
Hi Jan,
Jan Kratochvil <jan.kratochvil@redhat.com> writes:
> [ Cc to gdb-patches has been lost. ]
> On Sun, 20 May 2012 15:09:19 +0200, Jan Kratochvil wrote:
> Hi John,
>
> On Sun, 20 May 2012 14:34:05 +0200, John Steele Scott wrote:
>> basic_lookup_transparent_type will only do one psymbol->symbol expansion per
>> call. For a frequently referenced opaque type in a non-trivial program,
>> initially "ptype" will show it as "no data fields". But if I repeatedly
>> invoke ptype, eventually it resolves the type correctly.
>
> sorry I did not write a proper reproducer + testcase for it but I believe the
> attached patch should fix it. It is probably a regression since introduction
> of quick_symbol_functions.
>
>
>> On the question of caching the producer info in the dwarf2_cu; I propose to
>> extract out the second half of producer_is_gxx_lt_4_6 into a new
>> check_producer function which will set cu->producer_is_gxx_lt_4_6 and
>> cu->producer_is_icc as appropriate (and then set cu->checked_producer).
>> producer_is_gxx_lt_4_6 and producer_is_icc will call check_producer if
>> cu->checked_producer is not set. Sound okay?
>
> Yes, I find such approach appropriate.
The below patch implements this.
I ran the full testsuite on amd64 with gcc (Ubuntu/Linaro 4.4.4-14ubuntu5.1)
4.4.5; it passes my testcase from
http://sourceware.org/ml/gdb-patches/2012-05/msg00763.html, and there are no
new failures.
I also ran the full testsuite with icc, as:
make -j10 check RUNTESTFLAGS="CC_FOR_TARGET=icc CFLAGS_FOR_TARGET='-debug
extended' CXX_FOR_TARGET=icpc CXXFLAGS_FOR_TARGET='-debug extended'". In
addition to fixing my testcase, this fixes the four similar broken cases in
gdb.base/opaque, now that set of tests all pass.
Two tests in gdb.base/type-opaque effectively changed polarity: previously
"opaque {struct,union} type resolving" failed, now those pass and "empty
{struct,union} type resolving" fail. As previously discussed, this is the
lesser of the two evils as far as I'm concerned.
The patch at http://sourceware.org/ml/gdb-patches/2012-05/msg00739.html is
still required to fix my non-trivial case, I hope that (or something like it)
can be committed soon.
thanks,
John
2012-05-24 John Steele Scott <toojays@toojays.net>
PR symtab/13277: Resolving opaque structures in ICC generated binaries.
* dwarf2read.c (struct dwarf2_cu) <producer_is_icc>: New field.
(producer_is_gxx_lt_4_6): Move the checking and caching to...
(check_producer): ... this new function, which also checks for ICC
and caches the result.
(producer_is_icc): New function.
(read_structure_type): Don't set TYPE_STUB_SUPPORTED if the
producer was ICC.
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index b590134..2afefaf 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -429,12 +429,13 @@ struct dwarf2_cu
unoptimized code. For a future better test see GCC PR other/32998. */
unsigned int has_loclist : 1;
- /* These cache the results of producer_is_gxx_lt_4_6.
- CHECKED_PRODUCER is set if PRODUCER_IS_GXX_LT_4_6 is valid. This
- information is cached because profiling CU expansion showed
- excessive time spent in producer_is_gxx_lt_4_6. */
+ /* These cache the results for producer_is_gxx_lt_4_6 and producer_is_icc.
+ CHECKED_PRODUCER is set if both PRODUCER_IS_GXX_LT_4_6 and PRODUCER_IS_ICC
+ are valid. This information is cached because profiling CU expansion
+ showed excessive time spent in producer_is_gxx_lt_4_6. */
unsigned int checked_producer : 1;
unsigned int producer_is_gxx_lt_4_6 : 1;
+ unsigned int producer_is_icc : 1;
/* Non-zero if DW_AT_addr_base was found.
Used when processing DWO files. */
@@ -8271,16 +8272,14 @@ dwarf2_record_block_ranges (struct die_info *die, struct block *block,
}
}
-/* Check for GCC PR debug/45124 fix which is not present in any G++ version up
- to 4.5.any while it is present already in G++ 4.6.0 - the PR has been fixed
- during 4.6.0 experimental. */
+/* Check whether the producer field indicates either of GCC < 4.6, or the
+ Intel C/C++ compiler, and cache the result in CU. */
-static int
-producer_is_gxx_lt_4_6 (struct dwarf2_cu *cu)
+static void
+check_producer (struct dwarf2_cu *cu)
{
const char *cs;
int major, minor, release;
- int result = 0;
if (cu->producer == NULL)
{
@@ -8292,22 +8291,11 @@ producer_is_gxx_lt_4_6 (struct dwarf2_cu *cu)
for their space efficiency GDB cannot workaround gcc-4.5.x -gdwarf-4
combination. gcc-4.5.x -gdwarf-4 binaries have DW_AT_accessibility
interpreted incorrectly by GDB now - GCC PR debug/48229. */
-
- return 0;
- }
-
- if (cu->checked_producer)
- return cu->producer_is_gxx_lt_4_6;
-
- /* Skip any identifier after "GNU " - such as "C++" or "Java". */
-
- if (strncmp (cu->producer, "GNU ", strlen ("GNU ")) != 0)
- {
- /* For non-GCC compilers expect their behavior is DWARF version
- compliant. */
}
- else
+ else if (strncmp (cu->producer, "GNU ", strlen ("GNU ")) == 0)
{
+ /* Skip any identifier after "GNU " - such as "C++" or "Java". */
+
cs = &cu->producer[strlen ("GNU ")];
while (*cs && !isdigit (*cs))
cs++;
@@ -8316,13 +8304,30 @@ producer_is_gxx_lt_4_6 (struct dwarf2_cu *cu)
/* Not recognized as GCC. */
}
else
- result = major < 4 || (major == 4 && minor < 6);
+ cu->producer_is_gxx_lt_4_6 = major < 4 || (major == 4 && minor < 6);
+ }
+ else if (strncmp (cu->producer, "Intel(R) C", strlen ("Intel(R) C")) == 0)
+ cu->producer_is_icc = 1;
+ else
+ {
+ /* For other non-GCC compilers, expect their behavior is DWARF version
+ compliant. */
}
cu->checked_producer = 1;
- cu->producer_is_gxx_lt_4_6 = result;
+}
- return result;
+/* Check for GCC PR debug/45124 fix which is not present in any G++ version up
+ to 4.5.any while it is present already in G++ 4.6.0 - the PR has been fixed
+ during 4.6.0 experimental. */
+
+static int
+producer_is_gxx_lt_4_6 (struct dwarf2_cu *cu)
+{
+ if (!cu->checked_producer)
+ check_producer(cu);
+
+ return cu->producer_is_gxx_lt_4_6;
}
/* Return the default accessibility type if it is not overriden by
@@ -9005,6 +9010,18 @@ quirk_gcc_member_function_pointer (struct type *type, struct objfile *objfile)
smash_to_methodptr_type (type, new_type);
}
+/* Return non-zero if the CU's PRODUCER string matches the Intel C/C++ compiler
+ (icc). */
+
+static int
+producer_is_icc (struct dwarf2_cu *cu)
+{
+ if (!cu->checked_producer)
+ check_producer(cu);
+
+ return cu->producer_is_icc;
+}
+
/* Called when we find the DIE that starts a structure or union scope
(definition) to create a type for the structure or union. Fill in
the type's name and general properties; the members will not be
@@ -9107,7 +9124,14 @@ read_structure_type (struct die_info *die, struct dwarf2_cu *cu)
TYPE_LENGTH (type) = 0;
}
- TYPE_STUB_SUPPORTED (type) = 1;
+ if (producer_is_icc (cu))
+ {
+ /* ICC does not output the required DW_AT_declaration
+ on incomplete types, but gives them a size of zero. */
+ }
+ else
+ TYPE_STUB_SUPPORTED (type) = 1;
+
if (die_is_declaration (die, cu))
TYPE_STUB (type) = 1;
else if (attr == NULL && die->child == NULL