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[PATCH 1/2] In cp_print_value_fields() obey dont_print_statmem=1 explicitly passed from cp_print_static_field()

From: Patrick Frants <osscontribute at gmail dot com>
To: gdb-patches at sourceware dot org
Cc: Patrick Frants <osscontribute at gmail dot com>
Date: Wed, 18 Oct 2017 15:17:28 +0200
Subject: [PATCH 1/2] In cp_print_value_fields() obey dont_print_statmem=1 explicitly passed from cp_print_static_field()
Authentication-results: sourceware.org; auth=none

This fixes Bug gdb/13669 (https://sourceware.org/bugzilla/show_bug.cgi?id=13669)

cp_print_value_fields() in cp-valprint.c optionally skips static members based on options->static_field_print. Additionally cp_print_value_fields() has a parameter dont_print_statmem, which instructs the current invocation to skip static members. The "if () continue" statement (line 236) fails to take into account this parameter and therefore gdb gets into an infinite recursion involving cp_print_value_fields() and cp_print_static_field().

Sample backtrace (note dont_print_statmem=1):
(gdb) bt 30
#0  0x00007ffff754737d in __libc_sigaction () from target:/lib64/libc.so.6
#1  0x0000000000527c65 in gdb_demangle (name=0xd97683 "m_blendColour", options=3) at cp-support.c:1524
#2  0x0000000000646a6f in fprintf_symbol_filtered (stream=0x7fffffffd580, name=0xd97683 "m_blendColour", lang=<optimized out>, arg_mode=3) at utils.c:2433
#3  0x000000000052866f in cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16284, val=0x221f040, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:267
#4  0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16284, stream=0x7fffffffd580, val=0x221f040, type=<optimized out>) at cp-valprint.c:672
#5  cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16283, val=0x221eb90, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#6  0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16283, stream=0x7fffffffd580, val=0x221eb90, type=<optimized out>) at cp-valprint.c:672
#7  cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16282, val=0x221e710, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#8  0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16282, stream=0x7fffffffd580, val=0x221e710, type=<optimized out>) at cp-valprint.c:672
#9  cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16281, val=0x221f7b0, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#10 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16281, stream=0x7fffffffd580, val=0x221f7b0, type=<optimized out>) at cp-valprint.c:672
#11 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16280, val=0x221e100, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#12 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16280, stream=0x7fffffffd580, val=0x221e100, type=<optimized out>) at cp-valprint.c:672
#13 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16279, val=0x2213190, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#14 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16279, stream=0x7fffffffd580, val=0x2213190, type=<optimized out>) at cp-valprint.c:672
#15 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16278, val=0x2212d20, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#16 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16278, stream=0x7fffffffd580, val=0x2212d20, type=<optimized out>) at cp-valprint.c:672
#17 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16277, val=0x2212860, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#18 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16277, stream=0x7fffffffd580, val=0x2212860, type=<optimized out>) at cp-valprint.c:672
#19 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16276, val=0x2213660, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#20 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16276, stream=0x7fffffffd580, val=0x2213660, type=<optimized out>) at cp-valprint.c:672
#21 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16275, val=0x22121d0, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#22 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16275, stream=0x7fffffffd580, val=0x22121d0, type=<optimized out>) at cp-valprint.c:672
#23 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16274, val=0x2211e10, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#24 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16274, stream=0x7fffffffd580, val=0x2211e10, type=<optimized out>) at cp-valprint.c:672
#25 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16273, val=0x2214210, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#26 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16273, stream=0x7fffffffd580, val=0x2214210, type=<optimized out>) at cp-valprint.c:672
#27 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16272, val=0x2213d60, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
#28 0x0000000000529301 in cp_print_static_field (options=0x7fffffffcda0, recurse=16272, stream=0x7fffffffd580, val=0x2213d60, type=<optimized out>) at cp-valprint.c:672
#29 cp_print_value_fields (type=<optimized out>, type@entry=0xdc90c0, real_type=<optimized out>, offset=offset@entry=0, address=address@entry=6295612, stream=stream@entry=0x7fffffffd580, recurse=recurse@entry=16271, val=0x22137d0, options=0x7fffffffcda0, dont_print_vb=0x0, dont_print_statmem=1) at cp-valprint.c:333
(More stack frames follow...)

------------------------------------------------
REPRODUCTION:
A unittest has been added as two files:
  binutils-gdb/gdb/testsuite/gdb.cp/printstaticrecursion.exp
  binutils-gdb/gdb/testsuite/gdb.cp/printstaticrecursion.cc

---
 gdb/cp-valprint.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/cp-valprint.c b/gdb/cp-valprint.c
index fb9bfd904f..9dda6e2e5c 100644
--- a/gdb/cp-valprint.c
+++ b/gdb/cp-valprint.c
@@ -230,7 +230,7 @@ cp_print_value_fields (struct type *type, struct type *real_type,
 	  const gdb_byte *valaddr = value_contents_for_printing (val);
 
 	  /* If requested, skip printing of static fields.  */
-	  if (!options->static_field_print
+	  if ( (!options->static_field_print || dont_print_statmem)
 	      && field_is_static (&TYPE_FIELD (type, i)))
 	    continue;
 
-- 
2.14.0

Follow-Ups:
- [PATCH 2/2] Add unit test for bug 13669 "Infinite recursion in cp_print_value_fields"
  - From: Patrick Frants
- Re: [PATCH 1/2] In cp_print_value_fields() obey dont_print_statmem=1 explicitly passed from cp_print_static_field()
  - From: Simon Marchi

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