[sanitizer_common] Fuchsia-specific symbolizer

Summary:
Fuchsia doesn't support built-in symbolization per se at all.
Instead, it always emits a Fuchsia-standard "symbolizer markup"
format that makes it possible for a post-processing filter to
massage the logs into symbolized format.  Hence, it does not
support user-specified formatting options for backtraces or other
symbolization.

Reviewers: vitalybuka, alekseyshl, kcc

Subscribers: kubamracek, mgorny, phosek, filcab, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D36032

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@309760 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 109 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_symbolizer_fuchsia.cc b/lib/sanitizer_common/sanitizer_symbolizer_fuchsia.cc
new file mode 100644
index 000000000..8e383dd8f
--- /dev/null
+++ b/lib/sanitizer_common/sanitizer_symbolizer_fuchsia.cc
@@ -0,0 +1,109 @@
+//===-- sanitizer_symbolizer_fuchsia.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 various sanitizers' runtime libraries.
+//
+// Implementation of Fuchsia-specific symbolizer.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+#if SANITIZER_FUCHSIA
+
+#include "sanitizer_fuchsia.h"
+#include "sanitizer_symbolizer.h"
+
+namespace __sanitizer {
+
+// For Fuchsia we don't do any actual symbolization per se.
+// Instead, we emit text containing raw addresses and raw linkage
+// symbol names, embedded in Fuchsia's symbolization markup format.
+// Fuchsia's logging infrastructure emits enough information about
+// process memory layout that a post-processing filter can do the
+// symbolization and pretty-print the markup.
+// TODO(mcgrathr): URL to markup format document
+
+// This is used by UBSan for type names, and by ASan for global variable names.
+constexpr const char *kFormatDemangle = "{{{symbol:%s}}}";
+constexpr uptr kFormatDemangleMax = 1024;  // Arbitrary.
+
+// Function name or equivalent from PC location.
+constexpr const char *kFormatFunction = "{{{pc:%p}}}";
+constexpr uptr kFormatFunctionMax = 64; // More than big enough for 64-bit hex.
+
+// Global variable name or equivalent from data memory address.
+constexpr const char *kFormatData = "{{{data:%p}}}";
+
+// One frame in a backtrace (printed on a line by itself).
+constexpr const char *kFormatFrame = "{{{bt:%u:%p}}}";
+
+// This is used by UBSan for type names, and by ASan for global variable names.
+// It's expected to return a static buffer that will be reused on each call.
+const char *Symbolizer::Demangle(const char *name) {
+  static char buffer[kFormatDemangleMax];
+  internal_snprintf(buffer, sizeof(buffer), kFormatDemangle, name);
+  return buffer;
+}
+
+// This is used mostly for suppression matching.  Making it work
+// would enable "interceptor_via_lib" suppressions.  It's also used
+// once in UBSan to say "in module ..." in a message that also
+// includes an address in the module, so post-processing can already
+// pretty-print that so as to indicate the module.
+bool Symbolizer::GetModuleNameAndOffsetForPC(uptr pc, const char **module_name,
+                                             uptr *module_address) {
+  return false;
+}
+
+// This is used in some places for suppression checking, which we
+// don't really support for Fuchsia.  It's also used in UBSan to
+// identify a PC location to a function name, so we always fill in
+// the function member with a string containing markup around the PC
+// value.
+// TODO(mcgrathr): Under SANITIZER_GO, it's currently used by TSan
+// to render stack frames, but that should be changed to use
+// RenderStackFrame.
+SymbolizedStack *Symbolizer::SymbolizePC(uptr addr) {
+  SymbolizedStack *s = SymbolizedStack::New(addr);
+  char buffer[kFormatFunctionMax];
+  internal_snprintf(buffer, sizeof(buffer), kFormatFunction, addr);
+  s->info.function = internal_strdup(buffer);
+  return s;
+}
+
+// Always claim we succeeded, so that RenderDataInfo will be called.
+bool Symbolizer::SymbolizeData(uptr addr, DataInfo *info) {
+  info->Clear();
+  info->start = addr;
+  return true;
+}
+
+// We ignore the format argument to __sanitizer_symbolize_global.
+void RenderData(InternalScopedString *buffer, const char *format,
+                const DataInfo *DI, const char *strip_path_prefix) {
+  buffer->append(kFormatData, DI->start);
+}
+
+// We don't support the stack_trace_format flag at all.
+void RenderFrame(InternalScopedString *buffer, const char *format, int frame_no,
+                 const AddressInfo &info, bool vs_style,
+                 const char *strip_path_prefix, const char *strip_func_prefix) {
+  buffer->append(kFormatFrame, frame_no, info.address);
+}
+
+Symbolizer *Symbolizer::PlatformInit() {
+  return new(symbolizer_allocator_) Symbolizer({});
+}
+
+void Symbolizer::LateInitialize() {
+  Symbolizer::GetOrInit();
+}
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_FUCHSIA