[Sanitizer] Add rudimentary support for using libbacktrace in symbolizer.

More steps are needed to actually make it usable:
* sanitizer runtimes should be compiled with -DSANITIZER_LIBBACKTRACE.
* libbacktrace headers should be installed.
* user has to manually link in libbacktrace.a into the executable.

We can easily solve the first two problems in the build system, but
detecting/linking libbacktrace to all the tests we have and end-user programs
is more challenging (and will unlikely work w/o Driver support).

Based on the patch by Jakub Jelinek!

llvm-svn: 195837

compiler-rt/lib/sanitizer_common/CMakeLists.txt

@@ -28,6 +28,7 @@ set(SANITIZER_LIBCDEP_SOURCES
   sanitizer_posix_libcdep.cc
   sanitizer_stacktrace_libcdep.cc
   sanitizer_stoptheworld_linux_libcdep.cc
+  sanitizer_symbolizer_libbacktrace.cc
   sanitizer_symbolizer_libcdep.cc
   sanitizer_symbolizer_posix_libcdep.cc)
 
@@ -65,6 +66,7 @@ set(SANITIZER_HEADERS
   sanitizer_stoptheworld.h
   sanitizer_suppressions.h
   sanitizer_symbolizer.h
+  sanitizer_symbolizer_libbacktrace.h
   sanitizer_syscall_generic.inc
   sanitizer_syscall_linux_x86_64.inc
   sanitizer_thread_registry.h)

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libbacktrace.cc

@@ -0,0 +1,146 @@
+//===-- sanitizer_symbolizer_libbacktrace.cc ------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+// Libbacktrace implementation of symbolizer parts.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+
+#include "sanitizer_internal_defs.h"
+#include "sanitizer_symbolizer.h"
+#include "sanitizer_symbolizer_libbacktrace.h"
+
+#if SANITIZER_LIBBACKTRACE
+# include "backtrace-supported.h"
+# if SANITIZER_POSIX && BACKTRACE_SUPPORTED && !BACKTRACE_USES_MALLOC
+#  include "backtrace.h"
+# else
+#  define SANITIZER_LIBBACKTRACE 0
+# endif
+#endif
+
+namespace __sanitizer {
+
+#if SANITIZER_LIBBACKTRACE
+
+namespace {
+
+struct SymbolizeCodeData {
+  AddressInfo *frames;
+  uptr n_frames;
+  uptr max_frames;
+  const char *module_name;
+  uptr module_offset;
+};
+
+extern "C" {
+static int SymbolizeCodePCInfoCallback(void *vdata, uintptr_t addr,
+                                       const char *filename, int lineno,
+                                       const char *function) {
+  SymbolizeCodeData *cdata = (SymbolizeCodeData *)vdata;
+  if (function) {
+    AddressInfo *info = &cdata->frames[cdata->n_frames++];
+    info->Clear();
+    info->FillAddressAndModuleInfo(addr, cdata->module_name,
+                                   cdata->module_offset);
+    info->function = internal_strdup(function);
+    if (filename)
+      info->file = internal_strdup(filename);
+    info->line = lineno;
+    if (cdata->n_frames == cdata->max_frames)
+      return 1;
+  }
+  return 0;
+}
+
+static void SymbolizeCodeCallback(void *vdata, uintptr_t addr,
+                                  const char *symname, uintptr_t, uintptr_t) {
+  SymbolizeCodeData *cdata = (SymbolizeCodeData *)vdata;
+  if (symname) {
+    AddressInfo *info = &cdata->frames[0];
+    info->Clear();
+    info->FillAddressAndModuleInfo(addr, cdata->module_name,
+                                   cdata->module_offset);
+    info->function = internal_strdup(symname);
+    cdata->n_frames = 1;
+  }
+}
+
+static void SymbolizeDataCallback(void *vdata, uintptr_t, const char *symname,
+                                  uintptr_t symval, uintptr_t symsize) {
+  DataInfo *info = (DataInfo *)vdata;
+  if (symname && symval) {
+    info->name = internal_strdup(symname);
+    info->start = symval;
+    info->size = symsize;
+  }
+}
+
+static void ErrorCallback(void *, const char *, int) {}
+}  // extern "C"
+
+}  // namespace
+
+LibbacktraceSymbolizer *LibbacktraceSymbolizer::get(LowLevelAllocator *alloc) {
+  // State created in backtrace_create_state is leaked.
+  void *state = (void *)(backtrace_create_state("/proc/self/exe", 0,
+                                                ErrorCallback, NULL));
+  if (!state)
+    return 0;
+  return new(*alloc) LibbacktraceSymbolizer(state);
+}
+
+uptr LibbacktraceSymbolizer::SymbolizeCode(uptr addr, AddressInfo *frames,
+                                           uptr max_frames,
+                                           const char *module_name,
+                                           uptr module_offset) {
+  SymbolizeCodeData data;
+  data.frames = frames;
+  data.n_frames = 0;
+  data.max_frames = max_frames;
+  data.module_name = module_name;
+  data.module_offset = module_offset;
+  backtrace_pcinfo((backtrace_state *)state_, addr, SymbolizeCodePCInfoCallback,
+                   ErrorCallback, &data);
+  if (data.n_frames)
+    return data.n_frames;
+  backtrace_syminfo((backtrace_state *)state_, addr, SymbolizeCodeCallback,
+                    ErrorCallback, &data);
+  return data.n_frames;
+}
+
+bool LibbacktraceSymbolizer::SymbolizeData(DataInfo *info) {
+  backtrace_syminfo((backtrace_state *)state_, info->address,
+                    SymbolizeDataCallback, ErrorCallback, info);
+  return true;
+}
+
+#else  // SANITIZER_LIBBACKTRACE
+
+LibbacktraceSymbolizer *LibbacktraceSymbolizer::get(LowLevelAllocator *alloc) {
+  return 0;
+}
+
+uptr LibbacktraceSymbolizer::SymbolizeCode(uptr addr, AddressInfo *frames,
+                                           uptr max_frames,
+                                           const char *module_name,
+                                           uptr module_offset) {
+  (void)state_;
+  return 0;
+}
+
+bool LibbacktraceSymbolizer::SymbolizeData(DataInfo *info) {
+  return false;
+}
+
+#endif  // SANITIZER_LIBBACKTRACE
+
+}  // namespace __sanitizer

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libbacktrace.h

@@ -0,0 +1,40 @@
+//===-- sanitizer_symbolizer_libbacktrace.h -------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+// Header for libbacktrace symbolizer.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+#include "sanitizer_common.h"
+#include "sanitizer_symbolizer.h"
+
+#ifndef SANITIZER_LIBBACKTRACE
+# define SANITIZER_LIBBACKTRACE 0
+#endif
+
+namespace __sanitizer {
+
+class LibbacktraceSymbolizer {
+ public:
+  static LibbacktraceSymbolizer *get(LowLevelAllocator *alloc);
+
+  uptr SymbolizeCode(uptr addr, AddressInfo *frames, uptr max_frames,
+                     const char *module_name, uptr module_offset);
+
+  bool SymbolizeData(DataInfo *info);
+
+ private:
+  explicit LibbacktraceSymbolizer(void *state) : state_(state) {}
+
+  void *state_;  // Leaked.
+};
+
+}  // namespace __sanitizer

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc

@@ -21,6 +21,7 @@
 #include "sanitizer_placement_new.h"
 #include "sanitizer_procmaps.h"
 #include "sanitizer_symbolizer.h"
+#include "sanitizer_symbolizer_libbacktrace.h"
 
 #include <errno.h>
 #include <stdlib.h>
@@ -386,10 +387,12 @@ class InternalSymbolizer {
 class POSIXSymbolizer : public Symbolizer {
  public:
   POSIXSymbolizer(ExternalSymbolizer *external_symbolizer,
-                  InternalSymbolizer *internal_symbolizer)
+                  InternalSymbolizer *internal_symbolizer,
+                  LibbacktraceSymbolizer *libbacktrace_symbolizer)
       : Symbolizer(),
         external_symbolizer_(external_symbolizer),
-        internal_symbolizer_(internal_symbolizer) {}
+        internal_symbolizer_(internal_symbolizer),
+        libbacktrace_symbolizer_(libbacktrace_symbolizer) {}
 
   uptr SymbolizeCode(uptr addr, AddressInfo *frames, uptr max_frames) {
     BlockingMutexLock l(&mu_);
@@ -400,9 +403,17 @@ class POSIXSymbolizer : public Symbolizer {
       return 0;
     const char *module_name = module->full_name();
     uptr module_offset = addr - module->base_address();
+    // First, try to use libbacktrace symbolizer (if it's available).
+    if (libbacktrace_symbolizer_ != 0) {
+      mu_.CheckLocked();
+      uptr res = libbacktrace_symbolizer_->SymbolizeCode(
+          addr, frames, max_frames, module_name, module_offset);
+      if (res > 0)
+        return res;
+    }
     const char *str = SendCommand(false, module_name, module_offset);
     if (str == 0) {
-      // External symbolizer was not initialized or failed. Fill only data
+      // Symbolizer was not initialized or failed. Fill only data
       // about module name and offset.
       AddressInfo *info = &frames[0];
       info->Clear();
@@ -463,6 +474,11 @@ class POSIXSymbolizer : public Symbolizer {
     info->address = addr;
     info->module = internal_strdup(module_name);
     info->module_offset = module_offset;
+    if (libbacktrace_symbolizer_ != 0) {
+      mu_.CheckLocked();
+      if (libbacktrace_symbolizer_->SymbolizeData(info))
+        return true;
+    }
     const char *str = SendCommand(true, module_name, module_offset);
     if (str == 0)
       return true;
@@ -474,7 +490,8 @@ class POSIXSymbolizer : public Symbolizer {
   }
 
   bool IsAvailable() {
-    return internal_symbolizer_ != 0 || external_symbolizer_ != 0;
+    return internal_symbolizer_ != 0 || external_symbolizer_ != 0 ||
+        libbacktrace_symbolizer_ != 0;
   }
 
   bool IsExternalAvailable() {
@@ -567,14 +584,19 @@ class POSIXSymbolizer : public Symbolizer {
 
   ExternalSymbolizer *external_symbolizer_;        // Leaked.
   InternalSymbolizer *const internal_symbolizer_;  // Leaked.
+  LibbacktraceSymbolizer *libbacktrace_symbolizer_;  // Leaked.
 };
 
 Symbolizer *Symbolizer::PlatformInit(const char *path_to_external) {
   InternalSymbolizer* internal_symbolizer =
       InternalSymbolizer::get(&symbolizer_allocator_);
   ExternalSymbolizer *external_symbolizer = 0;
+  LibbacktraceSymbolizer *libbacktrace_symbolizer = 0;
 
   if (!internal_symbolizer) {
+    libbacktrace_symbolizer =
+        LibbacktraceSymbolizer::get(&symbolizer_allocator_);
+    if (!libbacktrace_symbolizer) {
       // Find path to llvm-symbolizer if it's not provided.
       if (!path_to_external)
         path_to_external = FindPathToBinary("llvm-symbolizer");
@@ -582,9 +604,10 @@ Symbolizer *Symbolizer::PlatformInit(const char *path_to_external) {
         external_symbolizer = new(symbolizer_allocator_)
             ExternalSymbolizer(path_to_external);
     }
+  }
 
-  return new(symbolizer_allocator_)
-      POSIXSymbolizer(external_symbolizer, internal_symbolizer);
+  return new(symbolizer_allocator_) POSIXSymbolizer(
+      external_symbolizer, internal_symbolizer, libbacktrace_symbolizer);
 }
 
 }  // namespace __sanitizer