Signal thread names in instrumented binaries, even when a debugger is not attached.

base/debug/profiler.cc

Index: base/debug/profiler.cc
diff --git a/base/debug/profiler.cc b/base/debug/profiler.cc
index e1f2514ab1936ef7c78bc88a7d700d313b7a3418..2d9c8243ac6ad7241d34b601982a44290eb56540 100644
--- a/base/debug/profiler.cc
+++ b/base/debug/profiler.cc
@@ -88,17 +88,34 @@ ReturnAddressLocationResolver GetProfilerReturnAddrResolutionFunc() {
 extern "C" IMAGE_DOS_HEADER __ImageBase;
 
 bool IsBinaryInstrumented() {

[jar (doing other things), 2012/05/30 22:30:10]

Does pulling in this function actually pull in all code in this file... and does
that pull in stuff from other files?

Is this really a minimal growth of the executable foot print?  Is this really a
tiny stub, and the real profiler bulk is linked in dynamically on demand?

[I assume you watch this class of stuff... and I assume that most of the
profiler is not currently in Chrome... but perhaps I'll be surprised! ;-) ]

-  HMODULE this_module = reinterpret_cast<HMODULE>(&__ImageBase);
-  base::win::PEImage image(this_module);
-
-  // This should be self-evident, soon as we're executing.
-  DCHECK(image.VerifyMagic());
+  enum InstrumentationCheckState {
+    UNINITIALIZED,
+    INSTRUMENTED_IMAGE,
+    NON_INSTRUMENTED_IMAGE,
+  };
+
+  static InstrumentationCheckState state = UNINITIALIZED;
+
+  if (state == UNINITIALIZED) {
+    HMODULE this_module = reinterpret_cast<HMODULE>(&__ImageBase);
+    base::win::PEImage image(this_module);
+
+    // Check to be sure our image is structured as we'd expect.
+    DCHECK(image.VerifyMagic());
+
+    // Syzygy-instrumented binaries contain a PE image section named ".thunks",
+    // and all Syzygy-modified binaries contain the ".syzygy" image section.
+    // This is a very fast check, as it only looks at the image header.
+    if ((image.GetImageSectionHeaderByName(".thunks") != NULL) &&
+        (image.GetImageSectionHeaderByName(".syzygy") != NULL)) {
+      state = INSTRUMENTED_IMAGE;
+    } else {
+      state = NON_INSTRUMENTED_IMAGE;
+    }
+  }
+  DCHECK(state != UNINITIALIZED);
 
-  // Syzygy-instrumented binaries contain a PE image section named ".thunks",
-  // and all Syzygy-modified binaries contain the ".syzygy" image section.
-  // This is a very fast check, as it only looks at the image header.
-  return (image.GetImageSectionHeaderByName(".thunks") != NULL) &&
-      (image.GetImageSectionHeaderByName(".syzygy") != NULL);
+  return state == INSTRUMENTED_IMAGE;
 }
 
 // Callback function to PEImage::EnumImportChunks.