More robust stack walks when the IP address in the context frame is invalid (or not in a known module).

This is achieved by:
1. Extending the span of the scan for return address in the conext frame.  Initially, I wanted to extend the span of the scan for all frames but then I noticed that there is code for ARM already that is extending the search only for the context frame.  This kind of makes sense so I decided to reuse the same idea everywhere.
2. Attempting to restore the EBP chain after a successful scan for return address so that the stackwalker can switch back to FRAME_TRUST_CFI for the rest of the frames when possible.

I also fixed the lint errors in the files touched.
Review URL: https://breakpad.appspot.com/605002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1193 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 4 insertions, 4 deletions

diff --git a/src/processor/stackwalker_amd64.cc b/src/processor/stackwalker_amd64.cc
index 737a2496..1cf9132e 100644
--- a/src/processor/stackwalker_amd64.cc
+++ b/src/processor/stackwalker_amd64.cc
@@ -102,10 +102,9 @@ StackwalkerAMD64::StackwalkerAMD64(const SystemInfo* system_info,
                   (sizeof(cfi_register_map_) / sizeof(cfi_register_map_[0]))) {
 }
 
-uint64_t StackFrameAMD64::ReturnAddress() const
-{
+uint64_t StackFrameAMD64::ReturnAddress() const {
   assert(context_validity & StackFrameAMD64::CONTEXT_VALID_RIP);
-  return context.rip;   
+  return context.rip;
 }
 
 StackFrame* StackwalkerAMD64::GetContextFrame() {
@@ -154,7 +153,8 @@ StackFrameAMD64* StackwalkerAMD64::GetCallerByStackScan(
   uint64_t last_rsp = last_frame->context.rsp;
   uint64_t caller_rip_address, caller_rip;
 
-  if (!ScanForReturnAddress(last_rsp, &caller_rip_address, &caller_rip)) {
+  if (!ScanForReturnAddress(last_rsp, &caller_rip_address, &caller_rip,
+                            frames.size() == 1 /* is_context_frame */)) {
     // No plausible return address was found.
     return NULL;
   }