Better testing for Stackwalker (#18). r=bryner

- Test StackwalkerX86 and StackwalkerPPC on the current process, if built
   by a supported compiler (gcc) on a supported (walkable) CPU (x86, ppc).
 - This test is not enabled by default because of certain optimizations
   that interfere with it (stack frame reuse, frame pointer omission).  See
   the comments at the top of stackwalker_selftest.cc.  To enable this
   test in the standard "make check" suite, configure with --enable-selftest.

http://groups.google.com/group/airbag-dev/browse_thread/thread/2ca1c8e72c809bec


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@35 4c0a9323-5329-0410-9bdc-e9ce6186880e

Makefile.am

@@ -89,9 +89,16 @@ check_PROGRAMS = \
 	src/processor/postfix_evaluator_unittest \
 	src/processor/range_map_unittest \
 	src/processor/source_line_resolver_unittest
+
+if SELFTEST
+check_PROGRAMS += \
+	src/processor/stackwalker_selftest
+endif SELFTEST
+
 check_SCRIPTS = \
 	src/processor/minidump_dump_test \
 	src/processor/minidump_stackwalk_test
+
 TESTS = $(check_PROGRAMS) $(check_SCRIPTS)
 TESTS_ENVIRONMENT =
 
@@ -119,6 +126,15 @@ src_processor_source_line_resolver_unittest_SOURCES = \
 src_processor_source_line_resolver_unittest_LDADD = \
 	src/processor/source_line_resolver.lo
 
+src_processor_stackwalker_selftest_SOURCES = \
+	src/processor/stackwalker_selftest.cc
+src_processor_stackwalker_selftest_LDADD = \
+	src/processor/minidump.lo \
+	src/processor/source_line_resolver.lo \
+	src/processor/stackwalker.lo \
+	src/processor/stackwalker_ppc.lo \
+	src/processor/stackwalker_x86.lo
+
 ## Non-installables
 noinst_PROGRAMS =
 noinst_SCRIPTS = $(check_SCRIPTS)

Makefile.in

@@ -74,7 +74,11 @@ check_PROGRAMS = src/processor/contained_range_map_unittest$(EXEEXT) \
 	src/processor/minidump_processor_unittest$(EXEEXT) \
 	src/processor/postfix_evaluator_unittest$(EXEEXT) \
 	src/processor/range_map_unittest$(EXEEXT) \
-	src/processor/source_line_resolver_unittest$(EXEEXT)
+	src/processor/source_line_resolver_unittest$(EXEEXT) \
+	$(am__EXEEXT_1)
+@SELFTEST_TRUE@am__append_1 = \
+@SELFTEST_TRUE@	src/processor/stackwalker_selftest
+
 noinst_PROGRAMS =
 DIST_COMMON = README $(am__configure_deps) $(dist_doc_DATA) \
 	$(srcdir)/Makefile.am $(srcdir)/Makefile.in \
@@ -111,6 +115,8 @@ am_src_libairbag_la_OBJECTS = src/processor/minidump.lo \
 	src/processor/stackwalker_x86.lo
 src_libairbag_la_OBJECTS = $(am_src_libairbag_la_OBJECTS)
 binPROGRAMS_INSTALL = $(INSTALL_PROGRAM)
+@SELFTEST_TRUE@am__EXEEXT_1 =  \
+@SELFTEST_TRUE@	src/processor/stackwalker_selftest$(EXEEXT)
 PROGRAMS = $(bin_PROGRAMS) $(noinst_PROGRAMS)
 am_src_processor_contained_range_map_unittest_OBJECTS =  \
 	src/processor/contained_range_map_unittest.$(OBJEXT)
@@ -156,6 +162,15 @@ src_processor_source_line_resolver_unittest_OBJECTS =  \
 	$(am_src_processor_source_line_resolver_unittest_OBJECTS)
 src_processor_source_line_resolver_unittest_DEPENDENCIES =  \
 	src/processor/source_line_resolver.lo
+am_src_processor_stackwalker_selftest_OBJECTS =  \
+	src/processor/stackwalker_selftest.$(OBJEXT)
+src_processor_stackwalker_selftest_OBJECTS =  \
+	$(am_src_processor_stackwalker_selftest_OBJECTS)
+src_processor_stackwalker_selftest_DEPENDENCIES =  \
+	src/processor/minidump.lo \
+	src/processor/source_line_resolver.lo \
+	src/processor/stackwalker.lo src/processor/stackwalker_ppc.lo \
+	src/processor/stackwalker_x86.lo
 SCRIPTS = $(noinst_SCRIPTS)
 DEFAULT_INCLUDES = -I. -I$(srcdir) -I$(top_builddir)/src
 depcomp = $(SHELL) $(top_srcdir)/autotools/depcomp
@@ -183,7 +198,8 @@ SOURCES = $(src_libairbag_la_SOURCES) \
 	$(src_processor_minidump_stackwalk_SOURCES) \
 	$(src_processor_postfix_evaluator_unittest_SOURCES) \
 	$(src_processor_range_map_unittest_SOURCES) \
-	$(src_processor_source_line_resolver_unittest_SOURCES)
+	$(src_processor_source_line_resolver_unittest_SOURCES) \
+	$(src_processor_stackwalker_selftest_SOURCES)
 DIST_SOURCES = $(src_libairbag_la_SOURCES) \
 	$(src_processor_contained_range_map_unittest_SOURCES) \
 	$(src_processor_minidump_dump_SOURCES) \
@@ -191,7 +207,8 @@ DIST_SOURCES = $(src_libairbag_la_SOURCES) \
 	$(src_processor_minidump_stackwalk_SOURCES) \
 	$(src_processor_postfix_evaluator_unittest_SOURCES) \
 	$(src_processor_range_map_unittest_SOURCES) \
-	$(src_processor_source_line_resolver_unittest_SOURCES)
+	$(src_processor_source_line_resolver_unittest_SOURCES) \
+	$(src_processor_stackwalker_selftest_SOURCES)
 dist_docDATA_INSTALL = $(INSTALL_DATA)
 DATA = $(dist_doc_DATA)
 ETAGS = etags
@@ -258,6 +275,8 @@ PACKAGE_TARNAME = @PACKAGE_TARNAME@
 PACKAGE_VERSION = @PACKAGE_VERSION@
 PATH_SEPARATOR = @PATH_SEPARATOR@
 RANLIB = @RANLIB@
+SELFTEST_FALSE = @SELFTEST_FALSE@
+SELFTEST_TRUE = @SELFTEST_TRUE@
 SET_MAKE = @SET_MAKE@
 SHELL = @SHELL@
 STRIP = @STRIP@
@@ -379,6 +398,16 @@ src_processor_source_line_resolver_unittest_SOURCES = \
 src_processor_source_line_resolver_unittest_LDADD = \
 	src/processor/source_line_resolver.lo
 
+src_processor_stackwalker_selftest_SOURCES = \
+	src/processor/stackwalker_selftest.cc
+
+src_processor_stackwalker_selftest_LDADD = \
+	src/processor/minidump.lo \
+	src/processor/source_line_resolver.lo \
+	src/processor/stackwalker.lo \
+	src/processor/stackwalker_ppc.lo \
+	src/processor/stackwalker_x86.lo
+
 noinst_SCRIPTS = $(check_SCRIPTS)
 src_processor_minidump_dump_SOURCES = \
 	src/processor/minidump_dump.cc
@@ -594,6 +623,12 @@ src/processor/source_line_resolver_unittest.$(OBJEXT):  \
 src/processor/source_line_resolver_unittest$(EXEEXT): $(src_processor_source_line_resolver_unittest_OBJECTS) $(src_processor_source_line_resolver_unittest_DEPENDENCIES) src/processor/$(am__dirstamp)
 	@rm -f src/processor/source_line_resolver_unittest$(EXEEXT)
 	$(CXXLINK) $(src_processor_source_line_resolver_unittest_LDFLAGS) $(src_processor_source_line_resolver_unittest_OBJECTS) $(src_processor_source_line_resolver_unittest_LDADD) $(LIBS)
+src/processor/stackwalker_selftest.$(OBJEXT):  \
+	src/processor/$(am__dirstamp) \
+	src/processor/$(DEPDIR)/$(am__dirstamp)
+src/processor/stackwalker_selftest$(EXEEXT): $(src_processor_stackwalker_selftest_OBJECTS) $(src_processor_stackwalker_selftest_DEPENDENCIES) src/processor/$(am__dirstamp)
+	@rm -f src/processor/stackwalker_selftest$(EXEEXT)
+	$(CXXLINK) $(src_processor_stackwalker_selftest_LDFLAGS) $(src_processor_stackwalker_selftest_OBJECTS) $(src_processor_stackwalker_selftest_LDADD) $(LIBS)
 
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
@@ -614,6 +649,7 @@ mostlyclean-compile:
 	-rm -f src/processor/stackwalker.lo
 	-rm -f src/processor/stackwalker_ppc.$(OBJEXT)
 	-rm -f src/processor/stackwalker_ppc.lo
+	-rm -f src/processor/stackwalker_selftest.$(OBJEXT)
 	-rm -f src/processor/stackwalker_x86.$(OBJEXT)
 	-rm -f src/processor/stackwalker_x86.lo
 
@@ -632,6 +668,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@src/processor/$(DEPDIR)/source_line_resolver_unittest.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@src/processor/$(DEPDIR)/stackwalker.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@src/processor/$(DEPDIR)/stackwalker_ppc.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@src/processor/$(DEPDIR)/stackwalker_selftest.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@src/processor/$(DEPDIR)/stackwalker_x86.Plo@am__quote@
 
 .cc.o:

configure

@@ -855,6 +855,8 @@ FFLAGS
 ac_ct_F77
 LIBTOOL
 LIBTOOL_DEPS
+SELFTEST_TRUE
+SELFTEST_FALSE
 LIBOBJS
 LTLIBOBJS'
 ac_subst_files=''
@@ -1458,6 +1460,8 @@ Optional Features:
   --enable-fast-install[=PKGS]
                           optimize for fast installation [default=yes]
   --disable-libtool-lock  avoid locking (might break parallel builds)
+  --enable-selftest       Run extra tests with "make check" (may conflict with
+                          optimizations) (default is no)
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -5150,7 +5154,7 @@ ia64-*-hpux*)
   ;;
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 5153 "configure"' > conftest.$ac_ext
+  echo '#line 5157 "configure"' > conftest.$ac_ext
   if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   (eval $ac_compile) 2>&5
   ac_status=$?
@@ -7315,11 +7319,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:7318: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:7322: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:7322: \$? = $ac_status" >&5
+   echo "$as_me:7326: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -7583,11 +7587,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:7586: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:7590: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:7590: \$? = $ac_status" >&5
+   echo "$as_me:7594: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -7687,11 +7691,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:7690: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:7694: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:7694: \$? = $ac_status" >&5
+   echo "$as_me:7698: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -10139,7 +10143,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10142 "configure"
+#line 10146 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -10239,7 +10243,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10242 "configure"
+#line 10246 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12607,11 +12611,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:12610: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:12614: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:12614: \$? = $ac_status" >&5
+   echo "$as_me:12618: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -12711,11 +12715,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:12714: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:12718: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:12718: \$? = $ac_status" >&5
+   echo "$as_me:12722: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -14281,11 +14285,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14284: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14288: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:14288: \$? = $ac_status" >&5
+   echo "$as_me:14292: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -14385,11 +14389,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14388: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14392: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:14392: \$? = $ac_status" >&5
+   echo "$as_me:14396: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -16615,11 +16619,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:16618: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:16622: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:16622: \$? = $ac_status" >&5
+   echo "$as_me:16626: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -16883,11 +16887,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:16886: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:16890: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:16890: \$? = $ac_status" >&5
+   echo "$as_me:16894: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -16987,11 +16991,11 @@ else
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:16990: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:16994: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:16994: \$? = $ac_status" >&5
+   echo "$as_me:16998: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -19875,6 +19879,36 @@ _ACEOF
 fi
 
 
+# Check whether --enable-selftest was given.
+if test "${enable_selftest+set}" = set; then
+  enableval=$enable_selftest; case "${enableval}" in
+                 yes)
+                   selftest=true
+                   ;;
+                 no)
+                   selftest=false
+                   ;;
+                 *)
+                   { { echo "$as_me:$LINENO: error: bad value ${enableval} for --enable-selftest" >&5
+echo "$as_me: error: bad value ${enableval} for --enable-selftest" >&2;}
+   { (exit 1); exit 1; }; }
+                   ;;
+               esac
+else
+  selftest=false
+fi
+
+
+
+if test x$selftest = xtrue; then
+  SELFTEST_TRUE=
+  SELFTEST_FALSE='#'
+else
+  SELFTEST_TRUE='#'
+  SELFTEST_FALSE=
+fi
+
+
 ac_config_files="$ac_config_files Makefile"
 
 cat >confcache <<\_ACEOF
@@ -19994,6 +20028,13 @@ echo "$as_me: error: conditional \"am__fastdepCXX\" was never defined.
 Usually this means the macro was only invoked conditionally." >&2;}
    { (exit 1); exit 1; }; }
 fi
+if test -z "${SELFTEST_TRUE}" && test -z "${SELFTEST_FALSE}"; then
+  { { echo "$as_me:$LINENO: error: conditional \"SELFTEST\" was never defined.
+Usually this means the macro was only invoked conditionally." >&5
+echo "$as_me: error: conditional \"SELFTEST\" was never defined.
+Usually this means the macro was only invoked conditionally." >&2;}
+   { (exit 1); exit 1; }; }
+fi
 
 : ${CONFIG_STATUS=./config.status}
 ac_clean_files_save=$ac_clean_files
@@ -20654,11 +20695,13 @@ FFLAGS!$FFLAGS$ac_delim
 ac_ct_F77!$ac_ct_F77$ac_delim
 LIBTOOL!$LIBTOOL$ac_delim
 LIBTOOL_DEPS!$LIBTOOL_DEPS$ac_delim
+SELFTEST_TRUE!$SELFTEST_TRUE$ac_delim
+SELFTEST_FALSE!$SELFTEST_FALSE$ac_delim
 LIBOBJS!$LIBOBJS$ac_delim
 LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
-  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 6; then
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 8; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5

configure.ac

@@ -47,5 +47,24 @@ AC_SUBST(LIBTOOL_DEPS)
 
 AC_HEADER_STDC
 
+AC_ARG_ENABLE(selftest,
+              AS_HELP_STRING([--enable-selftest],
+                             [Run extra tests with "make check" ]
+                             [(may conflict with optimizations) ]
+                             [(default is no)]),
+              [case "${enableval}" in
+                 yes)
+                   selftest=true
+                   ;;
+                 no)
+                   selftest=false
+                   ;;
+                 *)
+                   AC_MSG_ERROR(bad value ${enableval} for --enable-selftest)
+                   ;;
+               esac],
+              [selftest=false])
+AM_CONDITIONAL(SELFTEST, test x$selftest = xtrue)
+
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT

src/processor/stackwalker_selftest.cc

@@ -0,0 +1,252 @@
+// Copyright (C) 2006 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// stackwalker_selftest.cc: Tests StackwalkerX86 or StackwalkerPPC using the
+// running process' stack as test data, if running on an x86 or ppc and
+// compiled with gcc.  This test is not enabled in the "make check" suite
+// by default, because certain optimizations interfere with its proper
+// operation.  To turn it on, configure with --enable-selftest.
+//
+// Optimizations that cause problems:
+//  - stack frame reuse.  The Recursor function here calls itself with
+//    |return Recursor|.  When the caller's frame is reused, it will cause
+//    CountCallerFrames to correctly return the same number of frames
+//    in both the caller and callee.  This is considered an unexpected
+//    condition in the test, which expects a callee to have one more
+//    caller frame in the stack than its caller.
+//  - frame pointer omission.  Even with a stackwalker that understands
+//    this optimization, the code to harness debug information currently
+//    only exists to retrieve it from minidumps, not the current process.
+//
+// This test can also serve as a developmental and debugging aid if
+// PRINT_STACKS is defined.
+//
+// Author: Mark Mentovai
+
+#if defined(__GNUC__) && (defined(__i386__) || defined(__ppc__))
+
+
+#include <cstdio>
+
+#include "google/airbag_types.h"
+#include "google/stack_frame.h"
+#include "processor/memory_region.h"
+#include "processor/minidump_format.h"
+
+using google_airbag::MemoryRegion;
+using google_airbag::StackFrame;
+using google_airbag::StackFrames;
+
+#if defined(__i386__)
+#include "processor/stackwalker_x86.h"
+using google_airbag::StackwalkerX86;
+#elif defined(__ppc__)
+#include "processor/stackwalker_ppc.h"
+using google_airbag::StackwalkerPPC;
+#endif  // __i386__ || __ppc__
+
+#define RECURSION_DEPTH 100
+
+
+// A simple MemoryRegion subclass that provides direct access to this
+// process' memory space by pointer.
+class SelfMemoryRegion : public MemoryRegion {
+ public:
+  virtual u_int64_t GetBase() { return 0; }
+  virtual u_int32_t GetSize() { return 0xffffffff; }
+
+  bool GetMemoryAtAddress(u_int64_t address, u_int8_t*  value) {
+      return GetMemoryAtAddressInternal(address, value); }
+  bool GetMemoryAtAddress(u_int64_t address, u_int16_t* value) {
+      return GetMemoryAtAddressInternal(address, value); }
+  bool GetMemoryAtAddress(u_int64_t address, u_int32_t* value) {
+      return GetMemoryAtAddressInternal(address, value); }
+  bool GetMemoryAtAddress(u_int64_t address, u_int64_t* value) {
+      return GetMemoryAtAddressInternal(address, value); }
+
+ private:
+  template<typename T> bool GetMemoryAtAddressInternal(u_int64_t address,
+                                                       T*        value) {
+    u_int8_t* memory = 0;
+    *value = *reinterpret_cast<const T*>(&memory[address]);
+    return true;
+  }
+};
+
+
+#if defined(__i386__)
+
+// GetEBP returns the current value of the %ebp register.  Because it's
+// implemented as a function, %ebp itself contains GetEBP's frame pointer
+// and not the caller's frame pointer.  Dereference %ebp to obtain the
+// caller's frame pointer, which the compiler-generated preamble stored
+// on the stack (provided frame pointers are not being omitted.)  Because
+// this function depends on the compiler-generated preamble, inlining is
+// disabled.
+static u_int32_t GetEBP() __attribute__((noinline));
+static u_int32_t GetEBP() {
+  u_int32_t ebp;
+  __asm__ __volatile__(
+    "movl (%%ebp), %0"
+    : "=a" (ebp)
+  );
+  return ebp;
+}
+
+
+// GetEIP returns the instruction pointer identifying the next instruction
+// to execute after GetEIP returns.  It obtains this information from the
+// stack, where it was placed by the call instruction that called GetEIP.
+// This function depends on frame pointers not being omitted.  It is possible
+// to write a pure asm version of this routine that has no compiler-generated
+// preamble and uses %esp instead of %ebp; that would function in the
+// absence of frame pointers.  However, the simpler approach is used here
+// because GetEBP and stackwalking necessarily depends on access to frame
+// pointers.  Because this function depends on a call instruction and the
+// compiler-generated preamble, inlining is disabled.
+static u_int32_t GetEIP() __attribute__((noinline));
+static u_int32_t GetEIP() {
+  u_int32_t eip;
+  __asm__ __volatile__(
+    "movl 4(%%ebp), %0"
+    : "=a" (eip)
+  );
+  return eip;
+}
+
+
+#elif defined(__ppc__)
+
+
+// GetSP returns the current value of the %r1 register, which by convention,
+// is the stack pointer on ppc.  Because it's implemented as a function,
+// %r1 itself contains GetSP's own stack pointer and not the caller's stack 
+// pointer.  Dereference %r1 to obtain the caller's stack pointer, which the
+// compiler-generated prolog stored on the stack.  Because this function
+// depends on the compiler-generated prolog, inlining is disabled.
+static u_int32_t GetSP() __attribute__((noinline));
+static u_int32_t GetSP() {
+  u_int32_t sp;
+  __asm__ __volatile__(
+    "lwz %0, 0(r1)"
+    : "=r" (sp)
+  );
+  return sp;
+}
+
+
+// GetPC returns the program counter identifying the next instruction to
+// execute after GetPC returns.  It obtains this information from the
+// link register, where it was placed by the branch instruction that called
+// GetPC.  Because this function depends on the caller's use of a branch
+// instruction, inlining is disabled.
+static u_int32_t GetPC() __attribute__((noinline));
+static u_int32_t GetPC() {
+  u_int32_t lr;
+  __asm__ __volatile__(
+    "mflr %0"
+    : "=r" (lr)
+  );
+  return lr;
+}
+
+
+#endif  // __i386__ || __ppc__
+
+
+// CountCallerFrames returns the number of stack frames beneath the function
+// that called CountCallerFrames.  Because this function's return value
+// is dependent on the size of the stack beneath it, inlining is disabled,
+// and any function that calls this should not be inlined either.
+static unsigned int CountCallerFrames() __attribute__((noinline));
+static unsigned int CountCallerFrames() {
+  SelfMemoryRegion memory;
+
+#if defined(__i386__)
+  MDRawContextX86 context = MDRawContextX86();
+  context.eip = GetEIP();
+  context.ebp = GetEBP();
+
+  StackwalkerX86 stackwalker = StackwalkerX86(&context, &memory, NULL, NULL);
+#elif defined(__ppc__)
+  MDRawContextPPC context = MDRawContextPPC();
+  context.srr0 = GetPC();
+  context.gpr[1] = GetSP();
+
+  StackwalkerPPC stackwalker = StackwalkerPPC(&context, &memory, NULL, NULL);
+#endif  // __i386__ || __ppc__
+
+  StackFrames stack;
+  stackwalker.Walk(&stack);
+
+#ifdef PRINT_STACKS
+  printf("\n");
+  for(unsigned int frame_index = 0;
+      frame_index < stack.size();
+      ++frame_index) {
+    StackFrame *frame = &stack[frame_index];
+    printf("frame %-3d  instruction = 0x%08llx  frame_pointer = 0x%08llx\n",
+           frame_index, frame->instruction, frame->frame_pointer);
+  }
+#endif  // PRINT_STACKS
+
+  // Subtract 1 because the caller wants the number of frames beneath
+  // itself.  Because the caller called us, subract two for our frame and its
+  // frame, which are included in stack->size().
+  return stack.size() - 2;
+}
+
+
+// Recursor verifies that the number stack frames beneath itself is one more
+// than the number of stack frames beneath its parent.  When depth frames
+// have been reached, Recursor stops checking and returns success.  If the
+// frame count check fails at any depth, Recursor will stop and return false.
+// Because this calls CountCallerFrames, inlining is disabled.
+static bool Recursor(unsigned int depth, unsigned int parent_callers)
+    __attribute__((noinline));
+static bool Recursor(unsigned int depth, unsigned int parent_callers) {
+  unsigned int callers = CountCallerFrames();
+  if (callers != parent_callers + 1)
+    return false;
+
+  if (depth)
+    return Recursor(depth - 1, callers);
+
+  // depth == 0
+  return true;
+}
+
+
+// Because this calls CountCallerFrames, inlining is disabled - but because
+// it's main (and nobody calls it other than the entry point), it wouldn't
+// be inlined anyway.
+int main(int argc, char** argv) __attribute__((noinline));
+int main(int argc, char** argv) {
+  return Recursor(RECURSION_DEPTH, CountCallerFrames()) ? 0 : 1;
+}
+
+
+#else  // __GNUC__ && (__i386__ || __ppc__)
+// Not gcc?  We use gcc's __asm__.
+// Not i386 or ppc?  We can only test stacks we know how to walk.
+
+
+int main(int argc, char **argv) {
+  // "make check" interprets an exit status of 77 to mean that the test is
+  // not supported.
+  return 77;
+}
+
+
+#endif  // __GNUC__ && (__i386__ || __ppc__)