1 files changed, 62 insertions, 24 deletions

diff --git a/libsanitizer/sanitizer_common/sanitizer_symbolizer.h b/libsanitizer/sanitizer_common/sanitizer_symbolizer.h
index 2c84773eebc..af93de75081 100644
--- a/libsanitizer/sanitizer_common/sanitizer_symbolizer.h
+++ b/libsanitizer/sanitizer_common/sanitizer_symbolizer.h
@@ -5,19 +5,14 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// Symbolizer is intended to be used by both
-// AddressSanitizer and ThreadSanitizer to symbolize a given
-// address. It is an analogue of addr2line utility and allows to map
-// instruction address to a location in source code at run-time.
+// Symbolizer is used by sanitizers to map instruction address to a location in
+// source code at run-time. Symbolizer either uses __sanitizer_symbolize_*
+// defined in the program, or (if they are missing) tries to find and
+// launch "llvm-symbolizer" commandline tool in a separate process and
+// communicate with it.
 //
-// Symbolizer is planned to use debug information (in DWARF format)
-// in a binary via interface defined in "llvm/DebugInfo/DIContext.h"
-//
-// Symbolizer code should be called from the run-time library of
-// dynamic tools, and generally should not call memory allocation
-// routines or other system library functions intercepted by those tools.
-// Instead, Symbolizer code should use their replacements, defined in
-// "compiler-rt/lib/sanitizer_common/sanitizer_libc.h".
+// Generally we should try to avoid calling system library functions during
+// symbolization (and use their replacements from sanitizer_libc.h instead).
 //===----------------------------------------------------------------------===//
 #ifndef SANITIZER_SYMBOLIZER_H
 #define SANITIZER_SYMBOLIZER_H
@@ -25,7 +20,6 @@
 #include "sanitizer_allocator_internal.h"
 #include "sanitizer_internal_defs.h"
 #include "sanitizer_libc.h"
-// WARNING: Do not include system headers here. See details above.
 
 namespace __sanitizer {
 
@@ -67,8 +61,24 @@ struct DataInfo {
   uptr size;
 };
 
-class SymbolizerInterface {
+class Symbolizer {
  public:
+  /// Returns platform-specific implementation of Symbolizer. The symbolizer
+  /// must be initialized (with init or disable) before calling this function.
+  static Symbolizer *Get();
+  /// Returns platform-specific implementation of Symbolizer, or null if not
+  /// initialized.
+  static Symbolizer *GetOrNull();
+  /// Returns platform-specific implementation of Symbolizer.  Will
+  /// automatically initialize symbolizer as if by calling Init(0) if needed.
+  static Symbolizer *GetOrInit();
+  /// Initialize and return the symbolizer, given an optional path to an
+  /// external symbolizer.  The path argument is only required for legacy
+  /// reasons as this function will check $PATH for an external symbolizer.  Not
+  /// thread safe.
+  static Symbolizer *Init(const char* path_to_external = 0);
+  /// Initialize the symbolizer in a disabled state.  Not thread safe.
+  static Symbolizer *Disable();
   // Fills at most "max_frames" elements of "frames" with descriptions
   // for a given address (in all inlined functions). Returns the number
   // of descriptions actually filled.
@@ -82,6 +92,9 @@ class SymbolizerInterface {
   virtual bool IsAvailable() {
     return false;
   }
+  virtual bool IsExternalAvailable() {
+    return false;
+  }
   // Release internal caches (if any).
   virtual void Flush() {}
   // Attempts to demangle the provided C++ mangled name.
@@ -89,17 +102,42 @@ class SymbolizerInterface {
     return name;
   }
   virtual void PrepareForSandboxing() {}
-  // Starts external symbolizer program in a subprocess. Sanitizer communicates
-  // with external symbolizer via pipes. If path_to_symbolizer is NULL or empty,
-  // tries to look for llvm-symbolizer in PATH.
-  virtual bool InitializeExternal(const char *path_to_symbolizer) {
-    return false;
-  }
-};
 
-// Returns platform-specific implementation of SymbolizerInterface. It can't be
-// used from multiple threads simultaneously.
-SANITIZER_WEAK_ATTRIBUTE SymbolizerInterface *getSymbolizer();
+  // Allow user to install hooks that would be called before/after Symbolizer
+  // does the actual file/line info fetching. Specific sanitizers may need this
+  // to distinguish system library calls made in user code from calls made
+  // during in-process symbolization.
+  typedef void (*StartSymbolizationHook)();
+  typedef void (*EndSymbolizationHook)();
+  // May be called at most once.
+  void AddHooks(StartSymbolizationHook start_hook,
+                EndSymbolizationHook end_hook);
+
+ private:
+  /// Platform-specific function for creating a Symbolizer object.
+  static Symbolizer *PlatformInit(const char *path_to_external);
+  /// Create a symbolizer and store it to symbolizer_ without checking if one
+  /// already exists.  Not thread safe.
+  static Symbolizer *CreateAndStore(const char *path_to_external);
+
+  static Symbolizer *symbolizer_;
+  static StaticSpinMutex init_mu_;
+
+ protected:
+  Symbolizer();
+
+  static LowLevelAllocator symbolizer_allocator_;
+
+  StartSymbolizationHook start_hook_;
+  EndSymbolizationHook end_hook_;
+  class SymbolizerScope {
+   public:
+    explicit SymbolizerScope(const Symbolizer *sym);
+    ~SymbolizerScope();
+   private:
+    const Symbolizer *sym_;
+  };
+};
 
 }  // namespace __sanitizer