Refactor some bits of StackWalkerX86 / StackFrameX86 out into their respective parent classes so they can be used by other architecture implementations.

R=jimb at http://breakpad.appspot.com/205001/show

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@703 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 35 insertions, 2 deletions

diff --git a/src/google_breakpad/processor/stackwalker.h b/src/google_breakpad/processor/stackwalker.h
index 36d721d1..8dd2a971 100644
--- a/src/google_breakpad/processor/stackwalker.h
+++ b/src/google_breakpad/processor/stackwalker.h
@@ -44,12 +44,12 @@
 #include <set>
 #include <string>
 #include "google_breakpad/common/breakpad_types.h"
+#include "google_breakpad/processor/code_modules.h"
+#include "google_breakpad/processor/memory_region.h"
 
 namespace google_breakpad {
 
 class CallStack;
-class CodeModules;
-class MemoryRegion;
 class MinidumpContext;
 class SourceLineResolverInterface;
 struct StackFrame;
@@ -108,6 +108,39 @@ class Stackwalker {
   // Returns false otherwise.
   bool InstructionAddressSeemsValid(u_int64_t address);
 
+  // Scan the stack starting at location_start, looking for an address
+  // that looks like a valid instruction pointer. Addresses must
+  // 1) be contained in the current stack memory
+  // 2) pass the checks in InstructionAddressSeemsValid
+  //
+  // Returns true if a valid-looking instruction pointer was found.
+  // When returning true, sets location_found to the address at which
+  // the value was found, and ip_found to the value contained at that
+  // location in memory.
+  template<typename InstructionType>
+  bool ScanForReturnAddress(InstructionType location_start,
+                            InstructionType *location_found,
+                            InstructionType *ip_found) {
+    const int kRASearchWords = 15;
+    for (InstructionType location = location_start;
+         location <= location_start + kRASearchWords * sizeof(InstructionType);
+         location += sizeof(InstructionType)) {
+      InstructionType ip;
+      if (!memory_->GetMemoryAtAddress(location, &ip))
+        break;
+
+      if (modules_ && modules_->GetModuleForAddress(ip) &&
+          InstructionAddressSeemsValid(ip)) {
+
+        *ip_found = ip;
+        *location_found = location;
+        return true;
+      }
+    }
+    // nothing found
+    return false;
+  }
+
   // Information about the system that produced the minidump.  Subclasses
   // and the SymbolSupplier may find this information useful.
   const SystemInfo *system_info_;