From 60469e2ac0248f29afb4a9247913410ecef8ddd4 Mon Sep 17 00:00:00 2001
From: Anna Zaks <ganna@apple.com>
Date: Fri, 15 Apr 2016 23:51:00 +0000
Subject: [PATCH] [sanitizers] Teach the internal demangler about Swift names

Add support for Swift names when symbolicating sanitizer traces. This is
now relevant since TSan and ASan support have been added to Swift on OS X.

Differential Revision: http://reviews.llvm.org/D19135

llvm-svn: 266494
---
 .../sanitizer_symbolizer_internal.h           |  2 +-
 .../sanitizer_symbolizer_mac.cc               |  4 +--
 .../sanitizer_symbolizer_posix_libcdep.cc     | 35 ++++++++++++++++++-
 .../tests/sanitizer_symbolizer_test.cc        | 10 ++++++
 4 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_internal.h b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_internal.h
index 12c70b602e24..ada059cd725d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_internal.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_internal.h
@@ -28,7 +28,7 @@ const char *ExtractUptr(const char *str, const char *delims, uptr *result);
 const char *ExtractTokenUpToDelimiter(const char *str, const char *delimiter,
                                       char **result);
 
-const char *DemangleCXXABI(const char *name);
+const char *DemangleSwiftAndCXX(const char *name);
 
 // SymbolizerTool is an interface that is implemented by individual "tools"
 // that can perform symbolication (external llvm-symbolizer, libbacktrace,
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.cc b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
index a963b75a6784..d591abca15df 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
@@ -32,7 +32,7 @@ bool DlAddrSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
   Dl_info info;
   int result = dladdr((const void *)addr, &info);
   if (!result) return false;
-  const char *demangled = DemangleCXXABI(info.dli_sname);
+  const char *demangled = DemangleSwiftAndCXX(info.dli_sname);
   stack->info.function = demangled ? internal_strdup(demangled) : nullptr;
   return true;
 }
@@ -41,7 +41,7 @@ bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) {
   Dl_info info;
   int result = dladdr((const void *)addr, &info);
   if (!result) return false;
-  const char *demangled = DemangleCXXABI(info.dli_sname);
+  const char *demangled = DemangleSwiftAndCXX(info.dli_sname);
   datainfo->name = internal_strdup(demangled);
   datainfo->start = (uptr)info.dli_saddr;
   return true;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
index 7de3dbd0890f..2abfc25bd01f 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
@@ -26,6 +26,7 @@
 #include "sanitizer_symbolizer_libbacktrace.h"
 #include "sanitizer_symbolizer_mac.h"
 
+#include <dlfcn.h>   // for dlsym()
 #include <errno.h>
 #include <stdlib.h>
 #include <sys/wait.h>
@@ -61,6 +62,38 @@ const char *DemangleCXXABI(const char *name) {
   return name;
 }
 
+// Attempts to demangle a Swift name. The demangler will return nullptr
+/// if a non-Swift name is passed in.
+const char *DemangleSwift(const char *name) {
+  // Not to call dlsym every time we demangle, check if we are dealing with
+  // Swift mangled name first.
+  if (name[0] != '_' || name[1] != 'T') {
+    return nullptr;
+  }
+
+  // As of now, there are no headers for the Swift runtime. Once they are
+  // present, we will weakly link since we do not require Swift runtime to be
+  // linked.
+  typedef char *(*swift_demangle_ft)(const char *mangledName,
+                                     size_t mangledNameLength,
+                                     char *outputBuffer,
+                                     size_t *outputBufferSize,
+                                     uint32_t flags);
+  swift_demangle_ft swift_demangle_f =
+    (swift_demangle_ft) dlsym(RTLD_DEFAULT, "swift_demangle");
+  if (swift_demangle_f)
+    return swift_demangle_f(name, internal_strlen(name), 0, 0, 0);
+
+  return nullptr;
+}
+
+const char *DemangleSwiftAndCXX(const char *name) {
+  CHECK(name);
+  if (const char *swift_demangled_name = DemangleSwift(name))
+    return swift_demangled_name;
+  return DemangleCXXABI(name);
+}
+
 bool SymbolizerProcess::StartSymbolizerSubprocess() {
   if (!FileExists(path_)) {
     if (!reported_invalid_path_) {
@@ -364,7 +397,7 @@ class InternalSymbolizer : public SymbolizerTool {
 #endif  // SANITIZER_SUPPORTS_WEAK_HOOKS
 
 const char *Symbolizer::PlatformDemangle(const char *name) {
-  return DemangleCXXABI(name);
+  return DemangleSwiftAndCXX(name);
 }
 
 void Symbolizer::PlatformPrepareForSandboxing() {}
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_symbolizer_test.cc b/compiler-rt/lib/sanitizer_common/tests/sanitizer_symbolizer_test.cc
index 429ac591e502..8ff8bbb6cb33 100644
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_symbolizer_test.cc
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_symbolizer_test.cc
@@ -55,4 +55,14 @@ TEST(Symbolizer, ExtractTokenUpToDelimiter) {
   InternalFree(token);
 }
 
+TEST(Symbolizer, DemangleSwiftAndCXX) {
+  // Swift names are not demangled in default llvm build because Swift
+  // runtime is not linked in.
+  EXPECT_STREQ("_TtSd", DemangleSwiftAndCXX("_TtSd"));
+  // Check that the rest demangles properly.
+  EXPECT_STREQ("f1(char*, int)", DemangleSwiftAndCXX("_Z2f1Pci"));
+  EXPECT_STREQ("foo", DemangleSwiftAndCXX("foo"));
+  EXPECT_STREQ("", DemangleSwiftAndCXX(""));
+}
+
 }  // namespace __sanitizer