Implement glue for V8 JIT code profiling.

base/debug/profiler.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_DEBUG_PROFILER_H
 #define BASE_DEBUG_PROFILER_H
 
 #include <string>
 
 #include "base/base_export.h"
@@ skipping 37 matching lines @@
 // This class of profiler does not play well with programs that look at the
 // return address, as does e.g. V8. V8 uses the return address to certain
 // runtime functions to find the JIT code that called it, and from there finds
 // the V8 data structures associated to the JS function involved.
 // A return address resolution function is used to fix this. It allows such
 // programs to resolve a location on stack where a return address originally
 // resided, to the shadow stack location where the profiler stashed it.
 typedef uintptr_t (*ReturnAddressLocationResolver)(
     uintptr_t return_addr_location);
 
-// If this binary is instrumented and the instrumentation supplies a return
-// address resolution function, finds and returns the address resolution
-// function. Otherwise returns NULL.
-BASE_EXPORT ReturnAddressLocationResolver
-    GetProfilerReturnAddrResolutionFunc();
+// This type declaration must match V8's FunctionEntryHook.
+typedef void (*DynamicFunctionEntryHook)(uintptr_t function,
+                                         uintptr_t return_addr_location);
+
+// The functions below here are to support profiling V8-generated code.
+// V8 has provisions for generating a call to an entry hook for newly generated
+// JIT code, and it can push symbol information on code generation and advise
+// when the garbage collector moves code. The functions declarations below here
+// make glue between V8's facilities and a profiler.
+
+// This type declaration must match V8's FunctionEntryHook.
+typedef void (*DynamicFunctionEntryHook)(uintptr_t function,
+                                         uintptr_t return_addr_location);
+
+typedef void (*AddDynamicSymbol)(
+    const void* address, size_t length, const char* name, size_t name_len);

[jar (doing other things), 2013/06/22 00:38:14]

nit: Chromium style guide suggests that for declaration and definitions [of
typedefs?? not just methods and functions?] when you have to wrap, put one
pramater decl on each line.

[Sigurður Ásgeirsson, 2013/06/27 17:42:35]

Done.

+typedef void (*MoveDynamicSymbol)(const void* address, const void* new_address);
+
+
+// If this binary is instrumented and the instrumentation supplies a function
+// for each of those purposes, find and return the the function in question.
+// Otherwise returns NULL.
+BASE_EXPORT ReturnAddressLocationResolver GetProfilerReturnAddrResolutionFunc();
+BASE_EXPORT DynamicFunctionEntryHook GetProfilerDynamicFunctionEntryHookFunc();
+BASE_EXPORT AddDynamicSymbol GetProfilerAddDynamicSymbolFunc();
+BASE_EXPORT MoveDynamicSymbol GetProfilerMoveDynamicSymbolFunc();
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_DEBUGGER_H