Create StackFrame::FRAME_TRUST_PREWALKED trust type.

This creates a new frame trust type for prewalked stack frames, as suggested in
the review of https://breakpad.appspot.com/620002/.

R=ted.mielczarek@gmail.com, mark@chromium.org

Review URL: https://breakpad.appspot.com/621002/



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1208 4c0a9323-5329-0410-9bdc-e9ce6186880e

3 files changed, 17 insertions, 8 deletions

diff --git a/src/google_breakpad/processor/stack_frame.h b/src/google_breakpad/processor/stack_frame.h
index 23e69bb4..b55eb9c7 100644
--- a/src/google_breakpad/processor/stack_frame.h
+++ b/src/google_breakpad/processor/stack_frame.h
@@ -45,12 +45,13 @@ struct StackFrame {
   // stack scanning, it can wind up with dubious frames.
   // In rough order of "trust metric".
   enum FrameTrust {
-    FRAME_TRUST_NONE,     // Unknown
-    FRAME_TRUST_SCAN,     // Scanned the stack, found this
-    FRAME_TRUST_CFI_SCAN, // Scanned the stack using call frame info, found this
-    FRAME_TRUST_FP,       // Derived from frame pointer
-    FRAME_TRUST_CFI,      // Derived from call frame info
-    FRAME_TRUST_CONTEXT   // Given as instruction pointer in a context
+    FRAME_TRUST_NONE,      // Unknown
+    FRAME_TRUST_SCAN,      // Scanned the stack, found this
+    FRAME_TRUST_CFI_SCAN,  // Found while scanning stack using call frame info
+    FRAME_TRUST_FP,        // Derived from frame pointer
+    FRAME_TRUST_CFI,       // Derived from call frame info
+    FRAME_TRUST_PREWALKED, // Explicitly provided by some external stack walker.
+    FRAME_TRUST_CONTEXT    // Given as instruction pointer in a context
   };
 
   StackFrame()
@@ -70,6 +71,8 @@ struct StackFrame {
     switch (trust) {
       case StackFrame::FRAME_TRUST_CONTEXT:
         return "given as instruction pointer in context";
+      case StackFrame::FRAME_TRUST_PREWALKED:
+        return "recovered by external stack walker";
       case StackFrame::FRAME_TRUST_CFI:
         return "call frame info";
       case StackFrame::FRAME_TRUST_CFI_SCAN:
diff --git a/src/processor/stackwalker_address_list.cc b/src/processor/stackwalker_address_list.cc
index fdc9b9ae..55656032 100644
--- a/src/processor/stackwalker_address_list.cc
+++ b/src/processor/stackwalker_address_list.cc
@@ -85,7 +85,7 @@ StackFrame* StackwalkerAddressList::GetCallerFrame(const CallStack* stack,
   // explicitly provided.
   StackFrame* frame = new StackFrame();
   frame->instruction = frames_[frame_index];
-  frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
+  frame->trust = StackFrame::FRAME_TRUST_PREWALKED;
   return frame;
 }
 
diff --git a/src/processor/stackwalker_address_list_unittest.cc b/src/processor/stackwalker_address_list_unittest.cc
index 8af63fb1..2eb36cd7 100644
--- a/src/processor/stackwalker_address_list_unittest.cc
+++ b/src/processor/stackwalker_address_list_unittest.cc
@@ -106,8 +106,14 @@ class StackwalkerAddressListTest : public testing::Test {
   void CheckCallStack(const CallStack& call_stack) {
     const std::vector<StackFrame*>* frames = call_stack.frames();
     ASSERT_EQ(arraysize(kDummyFrames), frames->size());
-    for (size_t i = 0; i < arraysize(kDummyFrames); ++i)
+    for (size_t i = 0; i < arraysize(kDummyFrames); ++i) {
       ASSERT_EQ(kDummyFrames[i], frames->at(i)->instruction);
+      if (i == 0) {
+        ASSERT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frames->at(i)->trust);
+      } else {
+        ASSERT_EQ(StackFrame::FRAME_TRUST_PREWALKED, frames->at(i)->trust);
+      }
+    }
     ASSERT_EQ(static_cast<const CodeModule*>(&module2), frames->at(0)->module);
     ASSERT_EQ(static_cast<const CodeModule*>(&module2), frames->at(1)->module);
     ASSERT_EQ(static_cast<const CodeModule*>(&module2), frames->at(2)->module);