[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

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,

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;

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() {}

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