Get rid or heap allocation in stack sampler to avoid deadlocks.

test/cctest/test-log-ia32.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 //
 // Tests of profiler-related functions from log.h
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
 
 #include <stdlib.h>
 
 #include "v8.h"
 
@@ skipping 76 matching lines @@
 
 
 TEST(PureCStackTrace) {
   TickSample sample;
   StackTracer tracer(reinterpret_cast<unsigned int>(&sample));
   InitTraceEnv(&tracer, &sample);
   CFunc(0);
 #ifdef DEBUG
   // C stack trace works only in debug mode, in release mode EBP is
   // usually treated as a general-purpose register
+  CHECK_GT(sample.frames_count, 0);
   CheckRetAddrIsInCFunction(reinterpret_cast<unsigned int>(sample.stack[0]),
                             reinterpret_cast<unsigned int>(&CFunc));
-  CHECK_EQ(0, sample.stack[1]);
 #endif
 }
 
 
 // --- T r a c e   E x t e n s i o n ---
 
 class TraceExtension : public v8::Extension {
  public:
   TraceExtension() : v8::Extension("v8/trace", kSource) { }
   virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
@@ skipping 100 matching lines @@
               call_trace_code->instruction_size(),
               original, patch, sizeof(patch)));
 
   SetGlobalProperty("JSFuncDoTrace", v8::ToApi<Value>(call_trace));
 
   CompileRun(
       "function JSTrace() {"
       "  JSFuncDoTrace();"
       "};\n"
       "JSTrace();");
-  CHECK_NE(0, *(sample.stack));
+  CHECK_GT(sample.frames_count, 1);
   CheckRetAddrIsInFunction(
       reinterpret_cast<unsigned int>(sample.stack[0]),
       reinterpret_cast<unsigned int>(call_trace_code->instruction_start()),
       call_trace_code->instruction_size());
   Handle<JSFunction> js_trace(JSFunction::cast(*(v8::Utils::OpenHandle(
       *GetGlobalProperty("JSTrace")))));
   v8::internal::Code* js_trace_code = js_trace->code();
   CheckRetAddrIsInFunction(
       reinterpret_cast<unsigned int>(sample.stack[1]),
       reinterpret_cast<unsigned int>(js_trace_code->instruction_start()),
       js_trace_code->instruction_size());
 }
 
 #endif  // ENABLE_LOGGING_AND_PROFILING