[PATCH] Fix data symbolization with libbacktrace

[Jakub Jelinek]

Hi!

I've noticed that data symbolization doesn't really work now in GCC.
The problem is that DataInfo doesn't even have an address field (version
in compiler-rt), and in GCC version uses info->start, which is a field
that is supposed to be set by the method, not the address we should resolve.
>From the caller we only have module_offset computed, which is relative to
the start of the library, but libbacktrace actually wants the full address
instead.

The following patch fixes it.

Testcase:

ts.C:

#include <pthread.h>

int v;

int
foo (int x)
{
  if (x < 99)
    throw x;
  v++;
  return x;
}

void *
tf (void *)
{
  for (int i = 0; i < 100; i++)
    try { foo (i); } catch (int) {}
  return NULL;
}

int
do_main ()
{
  pthread_t th;
  if (pthread_create (&th, NULL, tf, NULL))
    return 0;
  v++;
  pthread_join (th, NULL);
  return 0;
}

tsm.C:

extern int do_main ();
int
main ()
{
  return do_main ();
}

and for both
$CXX -shared -fpic -o ts.so -g ts.C -fsanitize=thread
$CXX -o tsm -g tsm.C ./ts.so -fsanitize=thread
./tsm
and:
$CXX -o ts -g ts.C tsm.C -fsanitize=thread
./ts

it should print meaningful
  Location is global 'v' of size 4 at 0x0000006020e0 (ts+0x0000006020e0)
or similar line, not
  Location is global '<null>' of size 0 at 0x0000000000000000

--- compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libbacktrace.h.jj	2014-12-15 19:50:53.598624351 +0100
+++ compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libbacktrace.h	2014-12-15 19:51:24.811097009 +0100
@@ -35,7 +35,7 @@ class LibbacktraceSymbolizer {
   SymbolizedStack *SymbolizeCode(uptr addr, const char *module_name,
                                  uptr module_offset);
 
-  bool SymbolizeData(DataInfo *info);
+  bool SymbolizeData(uptr addr, DataInfo *info);
 
   // May return NULL if demangling failed.
   static char *Demangle(const char *name, bool always_alloc = false);
--- compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc.jj	2014-12-15 19:50:53.605624233 +0100
+++ compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc	2014-12-15 19:51:24.812096992 +0100
@@ -596,8 +596,8 @@ class POSIXSymbolizer : public Symbolize
     // First, try to use libbacktrace symbolizer (if it's available).
     if (libbacktrace_symbolizer_ != 0) {
       mu_.CheckLocked();
-      if (libbacktrace_symbolizer_->SymbolizeData(info))
-        return true;
+      if (libbacktrace_symbolizer_->SymbolizeData(addr, info))
+	return true;
     }
     const char *str = SendCommand(true, module_name, module_offset);
     if (str == 0)
--- compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libbacktrace.cc.jj	2014-12-15 19:50:53.600624317 +0100
+++ compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libbacktrace.cc	2014-12-15 19:52:23.602103720 +0100
@@ -173,8 +173,8 @@ SymbolizedStack *LibbacktraceSymbolizer:
   return data.first;
 }
 
-bool LibbacktraceSymbolizer::SymbolizeData(DataInfo *info) {
-  backtrace_syminfo((backtrace_state *)state_, info->address,
+bool LibbacktraceSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
+  backtrace_syminfo((backtrace_state *)state_, addr,
                     SymbolizeDataCallback, ErrorCallback, info);
   return true;
 }
@@ -192,7 +192,7 @@ SymbolizedStack *LibbacktraceSymbolizer:
   return nullptr;
 }
 
-bool LibbacktraceSymbolizer::SymbolizeData(DataInfo *info) {
+bool LibbacktraceSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
   return false;
 }
 

	Jakub