Adding support for mips.

Support for mips cpu is added to all breakapad targets including unittests.

BUG=none
TEST=unittests

Review URL: https://breakpad.appspot.com/614002



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1212 4c0a9323-5329-0410-9bdc-e9ce6186880e

10 files changed, 1435 insertions, 1 deletions

diff --git a/src/processor/minidump.cc b/src/processor/minidump.cc
index 851d0664..c7f2bcaa 100755
--- a/src/processor/minidump.cc
+++ b/src/processor/minidump.cc
@@ -844,6 +844,71 @@ bool MinidumpContext::Read(uint32_t expected_size) {
         break;
       }
 
+      case MD_CONTEXT_MIPS: {
+        if (expected_size != sizeof(MDRawContextMIPS)) {
+          BPLOG(ERROR) << "MinidumpContext MIPS size mismatch, " 
+                       << expected_size 
+                       << " != " 
+                       << sizeof(MDRawContextMIPS);
+          return false;
+        }
+
+        scoped_ptr<MDRawContextMIPS> context_mips(new MDRawContextMIPS());
+
+        // Set the context_flags member, which has already been read, and
+        // read the rest of the structure beginning with the first member
+        // after context_flags.
+        context_mips->context_flags = context_flags;
+
+        size_t flags_size = sizeof(context_mips->context_flags);
+        uint8_t* context_after_flags =
+            reinterpret_cast<uint8_t*>(context_mips.get()) + flags_size;
+        if (!minidump_->ReadBytes(context_after_flags,
+                                  sizeof(MDRawContextMIPS) - flags_size)) {
+          BPLOG(ERROR) << "MinidumpContext could not read MIPS context";
+          return false;
+        }
+
+        // Do this after reading the entire MDRawContext structure because
+        // GetSystemInfo may seek minidump to a new position.
+        if (!CheckAgainstSystemInfo(cpu_type)) {
+          BPLOG(ERROR) << "MinidumpContext MIPS does not match system info";
+          return false;
+        }
+
+        if (minidump_->swap()) {
+          // context_mips->context_flags was already swapped.
+          for (int ireg_index = 0;
+               ireg_index < MD_CONTEXT_MIPS_GPR_COUNT;
+               ++ireg_index) {
+            Swap(&context_mips->iregs[ireg_index]);
+          }
+	  Swap(&context_mips->mdhi);
+	  Swap(&context_mips->mdlo);
+          for (int dsp_index = 0;
+               dsp_index < MD_CONTEXT_MIPS_DSP_COUNT;
+               ++dsp_index) {
+            Swap(&context_mips->hi[dsp_index]);
+            Swap(&context_mips->lo[dsp_index]);
+          }
+	  Swap(&context_mips->dsp_control);
+          Swap(&context_mips->epc);
+          Swap(&context_mips->badvaddr);
+          Swap(&context_mips->status);
+          Swap(&context_mips->cause);
+          for (int fpr_index = 0;
+               fpr_index < MD_FLOATINGSAVEAREA_MIPS_FPR_COUNT;
+               ++fpr_index) {
+            Swap(&context_mips->float_save.regs[fpr_index]);
+          }
+          Swap(&context_mips->float_save.fpcsr);
+          Swap(&context_mips->float_save.fir);
+        }
+        context_.ctx_mips = context_mips.release();
+
+        break;
+      }
+
       default: {
         // Unknown context type - Don't log as an error yet. Let the
         // caller work that out.
@@ -901,6 +966,9 @@ bool MinidumpContext::GetInstructionPointer(uint64_t* ip) const {
   case MD_CONTEXT_X86:
     *ip = context_.x86->eip;
     break;
+  case MD_CONTEXT_MIPS:
+    *ip = context_.ctx_mips->epc;
+    break;
   default:
     // This should never happen.
     BPLOG(ERROR) << "Unknown CPU architecture in GetInstructionPointer";
@@ -965,6 +1033,15 @@ const MDRawContextARM* MinidumpContext::GetContextARM() const {
   return context_.arm;
 }
 
+const MDRawContextMIPS* MinidumpContext::GetContextMIPS() const {
+  if (GetContextCPU() != MD_CONTEXT_MIPS) {
+    BPLOG(ERROR) << "MinidumpContext cannot get MIPS context";
+    return NULL;
+  }
+
+  return context_.ctx_mips;
+}
+
 void MinidumpContext::FreeContext() {
   switch (GetContextCPU()) {
     case MD_CONTEXT_X86:
@@ -991,6 +1068,10 @@ void MinidumpContext::FreeContext() {
       delete context_.arm;
       break;
 
+    case MD_CONTEXT_MIPS:
+      delete context_.ctx_mips;
+      break;
+
     default:
       // There is no context record (valid_ is false) or there's a
       // context record for an unknown CPU (shouldn't happen, only known
@@ -1060,6 +1141,11 @@ bool MinidumpContext::CheckAgainstSystemInfo(uint32_t context_cpu_type) {
       if (system_info_cpu_type == MD_CPU_ARCHITECTURE_ARM)
         return_value = true;
       break;
+
+    case MD_CONTEXT_MIPS:
+      if (system_info_cpu_type == MD_CPU_ARCHITECTURE_MIPS)
+        return_value = true;
+      break;
   }
 
   BPLOG_IF(ERROR, !return_value) << "MinidumpContext CPU " <<
@@ -1338,6 +1424,53 @@ void MinidumpContext::Print() {
       break;
     }
 
+    case MD_CONTEXT_MIPS: {
+      const MDRawContextMIPS* context_mips = GetContextMIPS();
+      printf("MDRawContextMIPS\n");
+      printf("  context_flags        = 0x%x\n",
+             context_mips->context_flags);
+      for (int ireg_index = 0;
+           ireg_index < MD_CONTEXT_MIPS_GPR_COUNT;
+           ++ireg_index) {
+        printf("  iregs[%2d]           = 0x%" PRIx64 "\n",
+               ireg_index, context_mips->iregs[ireg_index]);
+      }
+      printf("  mdhi                 = 0x%" PRIx64 "\n",
+             context_mips->mdhi);
+      printf("  mdlo                 = 0x%" PRIx64 "\n",
+             context_mips->mdhi);
+      for (int dsp_index = 0;
+           dsp_index < MD_CONTEXT_MIPS_DSP_COUNT;
+           ++dsp_index) {
+        printf("  hi[%1d]              = 0x%" PRIx32 "\n",
+               dsp_index, context_mips->hi[dsp_index]);
+        printf("  lo[%1d]              = 0x%" PRIx32 "\n",
+               dsp_index, context_mips->lo[dsp_index]);
+      }
+      printf("  dsp_control          = 0x%" PRIx32 "\n",
+             context_mips->dsp_control);
+      printf("  epc                  = 0x%" PRIx64 "\n",
+             context_mips->epc);
+      printf("  badvaddr             = 0x%" PRIx64 "\n",
+             context_mips->badvaddr);
+      printf("  status               = 0x%" PRIx32 "\n",
+             context_mips->status);
+      printf("  cause                = 0x%" PRIx32 "\n",
+             context_mips->cause);
+
+      for (int fpr_index = 0;
+           fpr_index < MD_FLOATINGSAVEAREA_MIPS_FPR_COUNT;
+           ++fpr_index) {
+        printf("  float_save.regs[%2d] = 0x%" PRIx64 "\n",
+               fpr_index, context_mips->float_save.regs[fpr_index]);
+      }
+      printf("  float_save.fpcsr     = 0x%" PRIx32 "\n",
+             context_mips->float_save.fpcsr);
+      printf("  float_save.fir       = 0x%" PRIx32 "\n",
+             context_mips->float_save.fir);
+      break;
+    }
+
     default: {
       break;
     }
diff --git a/src/processor/minidump_processor.cc b/src/processor/minidump_processor.cc
index 51ee1164..17daa997 100644
--- a/src/processor/minidump_processor.cc
+++ b/src/processor/minidump_processor.cc
@@ -505,6 +505,11 @@ bool MinidumpProcessor::GetCPUInfo(Minidump *dump, SystemInfo *info) {
       break;
     }
 
+    case MD_CPU_ARCHITECTURE_MIPS: {
+      info->cpu = "mips";
+      break;
+    }
+
     default: {
       // Assign the numeric architecture ID into the CPU string.
       char cpu_string[7];
diff --git a/src/processor/minidump_stackwalk.cc b/src/processor/minidump_stackwalk.cc
index 756d8d0b..a49ed061 100644
--- a/src/processor/minidump_stackwalk.cc
+++ b/src/processor/minidump_stackwalk.cc
@@ -72,6 +72,7 @@ using google_breakpad::StackFrameSPARC;
 using google_breakpad::StackFrameX86;
 using google_breakpad::StackFrameAMD64;
 using google_breakpad::StackFrameARM;
+using google_breakpad::StackFrameMIPS;
 
 // Separator character for machine readable output.
 static const char kOutputSeparator = '|';
@@ -271,7 +272,63 @@ static void PrintStack(const CallStack *stack, const string &cpu) {
         sequence = PrintRegister("lr", frame_arm->context.iregs[14], sequence);
       if (frame_arm->context_validity & StackFrameARM::CONTEXT_VALID_PC)
         sequence = PrintRegister("pc", frame_arm->context.iregs[15], sequence);
-    }
+    } else if (cpu == "mips") {
+      const StackFrameMIPS* frame_mips =
+        reinterpret_cast<const StackFrameMIPS*>(frame);
+
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_GP)
+        sequence = PrintRegister64("gp",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_GP],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_SP)
+        sequence = PrintRegister64("sp",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_SP],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_FP)
+        sequence = PrintRegister64("fp",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_FP],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_RA)
+        sequence = PrintRegister64("ra",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_RA],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_PC)
+        sequence = PrintRegister64("pc", frame_mips->context.epc, sequence);
+
+      // Save registers s0-s7
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S0)
+        sequence = PrintRegister64("s0",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S0],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S1)
+        sequence = PrintRegister64("s1",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S1],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S2)
+        sequence = PrintRegister64("s2",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S2],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S3)
+        sequence = PrintRegister64("s3",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S3],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S4)
+        sequence = PrintRegister64("s4",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S4],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S5)
+        sequence = PrintRegister64("s5",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S5],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S6)
+        sequence = PrintRegister64("s6",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S6],
+                     sequence);
+      if (frame_mips->context_validity & StackFrameMIPS::CONTEXT_VALID_S7)
+        sequence = PrintRegister64("s7",
+                     frame_mips->context.iregs[MD_CONTEXT_MIPS_REG_S7],
+                     sequence);
+    } 
     printf("\n    Found by: %s\n", frame->trust_description().c_str());
   }
 }
diff --git a/src/processor/minidump_unittest.cc b/src/processor/minidump_unittest.cc
index d16bbc62..bb7dac64 100644
--- a/src/processor/minidump_unittest.cc
+++ b/src/processor/minidump_unittest.cc
@@ -1150,4 +1150,117 @@ TEST(Dump, OneExceptionARMOldFlags) {
   EXPECT_EQ(0x2e951ef7U, raw_context.cpsr);
 }
 
+TEST(Dump, OneExceptionMIPS) {
+  Dump dump(0, kLittleEndian);
+
+  MDRawContextMIPS raw_context;
+  raw_context.context_flags = MD_CONTEXT_MIPS_INTEGER;
+  raw_context.iregs[0] = 0x3ecba80d;
+  raw_context.iregs[1] = 0x382583b9;
+  raw_context.iregs[2] = 0x7fccc03f;
+  raw_context.iregs[3] = 0xf62f8ec2;
+  raw_context.iregs[4] = 0x46a6a6a8;
+  raw_context.iregs[5] = 0x6a5025e2;
+  raw_context.iregs[6] = 0xd9fabb4a;
+  raw_context.iregs[7] = 0x6913f540;
+  raw_context.iregs[8] = 0xbffe6eda;
+  raw_context.iregs[9] = 0xb2ce1e2d;
+  raw_context.iregs[10] = 0x659caaa4;
+  raw_context.iregs[11] = 0xf0e0d0c0;
+  raw_context.iregs[12] = 0xa9b8c7d6;
+  raw_context.iregs[13] = 0x12345678;
+  raw_context.iregs[14] = 0xabcd1234;
+  raw_context.iregs[15] = 0x10203040;
+  raw_context.iregs[16] = 0xa80d3ecb;
+  raw_context.iregs[17] = 0x83b93825;
+  raw_context.iregs[18] = 0xc03f7fcc;
+  raw_context.iregs[19] = 0x8ec2f62f;
+  raw_context.iregs[20] = 0xa6a846a6;
+  raw_context.iregs[21] = 0x25e26a50;
+  raw_context.iregs[22] = 0xbb4ad9fa;
+  raw_context.iregs[23] = 0xf5406913;
+  raw_context.iregs[24] = 0x6edabffe;
+  raw_context.iregs[25] = 0x1e2db2ce;
+  raw_context.iregs[26] = 0xaaa4659c;
+  raw_context.iregs[27] = 0xd0c0f0e0;
+  raw_context.iregs[28] = 0xc7d6a9b8;
+  raw_context.iregs[29] = 0x56781234;
+  raw_context.iregs[30] = 0x1234abcd;
+  raw_context.iregs[31] = 0x30401020;
+
+  Context context(dump, raw_context);
+
+  Exception exception(dump, context,
+                      0x1234abcd,  // Thread id.
+                      0xdcba4321,  // Exception code.
+                      0xf0e0d0c0,  // Exception flags.
+                      0x0919a9b9); // Exception address.
+  
+  dump.Add(&context);
+  dump.Add(&exception);
+  dump.Finish();
+
+  string contents;
+  ASSERT_TRUE(dump.GetContents(&contents));
+
+  istringstream minidump_stream(contents);
+  Minidump minidump(minidump_stream);
+  ASSERT_TRUE(minidump.Read());
+  ASSERT_EQ(1U, minidump.GetDirectoryEntryCount());
+
+  MinidumpException *md_exception = minidump.GetException();
+  ASSERT_TRUE(md_exception != NULL);
+
+  uint32_t thread_id;
+  ASSERT_TRUE(md_exception->GetThreadID(&thread_id));
+  ASSERT_EQ(0x1234abcdU, thread_id);
+
+  const MDRawExceptionStream* raw_exception = md_exception->exception();
+  ASSERT_TRUE(raw_exception != NULL);
+  EXPECT_EQ(0xdcba4321, raw_exception->exception_record.exception_code);
+  EXPECT_EQ(0xf0e0d0c0, raw_exception->exception_record.exception_flags);
+  EXPECT_EQ(0x0919a9b9U,
+            raw_exception->exception_record.exception_address);
+
+  MinidumpContext* md_context = md_exception->GetContext();
+  ASSERT_TRUE(md_context != NULL);
+  ASSERT_EQ((uint32_t) MD_CONTEXT_MIPS, md_context->GetContextCPU());
+  const MDRawContextMIPS* md_raw_context = md_context->GetContextMIPS();
+  ASSERT_TRUE(md_raw_context != NULL);
+  ASSERT_EQ((uint32_t) MD_CONTEXT_MIPS_INTEGER,
+            (md_raw_context->context_flags & MD_CONTEXT_MIPS_INTEGER));
+  EXPECT_EQ(0x3ecba80dU, raw_context.iregs[0]);
+  EXPECT_EQ(0x382583b9U, raw_context.iregs[1]);
+  EXPECT_EQ(0x7fccc03fU, raw_context.iregs[2]);
+  EXPECT_EQ(0xf62f8ec2U, raw_context.iregs[3]);
+  EXPECT_EQ(0x46a6a6a8U, raw_context.iregs[4]);
+  EXPECT_EQ(0x6a5025e2U, raw_context.iregs[5]);
+  EXPECT_EQ(0xd9fabb4aU, raw_context.iregs[6]);
+  EXPECT_EQ(0x6913f540U, raw_context.iregs[7]);
+  EXPECT_EQ(0xbffe6edaU, raw_context.iregs[8]);
+  EXPECT_EQ(0xb2ce1e2dU, raw_context.iregs[9]);
+  EXPECT_EQ(0x659caaa4U, raw_context.iregs[10]);
+  EXPECT_EQ(0xf0e0d0c0U, raw_context.iregs[11]);
+  EXPECT_EQ(0xa9b8c7d6U, raw_context.iregs[12]);
+  EXPECT_EQ(0x12345678U, raw_context.iregs[13]);
+  EXPECT_EQ(0xabcd1234U, raw_context.iregs[14]);
+  EXPECT_EQ(0x10203040U, raw_context.iregs[15]);
+  EXPECT_EQ(0xa80d3ecbU, raw_context.iregs[16]);
+  EXPECT_EQ(0x83b93825U, raw_context.iregs[17]);
+  EXPECT_EQ(0xc03f7fccU, raw_context.iregs[18]);
+  EXPECT_EQ(0x8ec2f62fU, raw_context.iregs[19]);
+  EXPECT_EQ(0xa6a846a6U, raw_context.iregs[20]);
+  EXPECT_EQ(0x25e26a50U, raw_context.iregs[21]);
+  EXPECT_EQ(0xbb4ad9faU, raw_context.iregs[22]);
+  EXPECT_EQ(0xf5406913U, raw_context.iregs[23]);
+  EXPECT_EQ(0x6edabffeU, raw_context.iregs[24]);
+  EXPECT_EQ(0x1e2db2ceU, raw_context.iregs[25]);
+  EXPECT_EQ(0xaaa4659cU, raw_context.iregs[26]);
+  EXPECT_EQ(0xd0c0f0e0U, raw_context.iregs[27]);
+  EXPECT_EQ(0xc7d6a9b8U, raw_context.iregs[28]);
+  EXPECT_EQ(0x56781234U, raw_context.iregs[29]);
+  EXPECT_EQ(0x1234abcdU, raw_context.iregs[30]);
+  EXPECT_EQ(0x30401020U, raw_context.iregs[31]);
+}
+
 }  // namespace
diff --git a/src/processor/stackwalker.cc b/src/processor/stackwalker.cc
index c8438ccf..8a6b422d 100644
--- a/src/processor/stackwalker.cc
+++ b/src/processor/stackwalker.cc
@@ -53,6 +53,7 @@
 #include "processor/stackwalker_x86.h"
 #include "processor/stackwalker_amd64.h"
 #include "processor/stackwalker_arm.h"
+#include "processor/stackwalker_mips.h"
 
 namespace google_breakpad {
 
@@ -230,6 +231,12 @@ Stackwalker* Stackwalker::StackwalkerForCPU(
                                              context->GetContextSPARC(),
                                              memory, modules, frame_symbolizer);
       break;
+ 
+    case MD_CONTEXT_MIPS:
+      cpu_stackwalker = new StackwalkerMIPS(system_info,
+                                            context->GetContextMIPS(),
+                                            memory, modules, frame_symbolizer);
+      break;
 
     case MD_CONTEXT_ARM:
       int fp_register = -1;
diff --git a/src/processor/stackwalker_mips.cc b/src/processor/stackwalker_mips.cc
new file mode 100644
index 00000000..74f7f57d
--- /dev/null
+++ b/src/processor/stackwalker_mips.cc
@@ -0,0 +1,300 @@
+// Copyright (c) 2013 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// stackwalker_mips.cc: MIPS-specific stackwalker.
+//
+// See stackwalker_mips.h for documentation.
+//
+// Author: Tata Elxsi
+
+#include "common/scoped_ptr.h"
+#include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/code_modules.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/source_line_resolver_interface.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "processor/cfi_frame_info.h"
+#include "processor/logging.h"
+#include "processor/postfix_evaluator-inl.h"
+#include "processor/stackwalker_mips.h"
+#include "processor/windows_frame_info.h"
+#include "google_breakpad/common/minidump_cpu_mips.h"
+
+namespace google_breakpad {
+
+StackwalkerMIPS::StackwalkerMIPS(const SystemInfo* system_info,
+                                 const MDRawContextMIPS* context,
+                                 MemoryRegion* memory,
+                                 const CodeModules* modules,
+                                 StackFrameSymbolizer* resolver_helper)
+    : Stackwalker(system_info, memory, modules, resolver_helper),
+      context_(context) {
+  if (memory_ && memory_->GetBase() + memory_->GetSize() - 1 > 0xffffffff) {
+    BPLOG(ERROR) << "Memory out of range for stackwalking: "
+                 << HexString(memory_->GetBase())
+                 << "+"
+                 << HexString(memory_->GetSize());
+    memory_ = NULL;
+  }
+}
+
+StackFrame* StackwalkerMIPS::GetContextFrame() {
+  if (!context_) {
+    BPLOG(ERROR) << "Can't get context frame without context.";
+    return NULL;
+  }
+
+  StackFrameMIPS* frame = new StackFrameMIPS();
+
+  // The instruction pointer is stored directly in a register, so pull it
+  // straight out of the CPU context structure.
+  frame->context = *context_;
+  frame->context_validity = StackFrameMIPS::CONTEXT_VALID_ALL;
+  frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
+  frame->instruction = frame->context.epc;
+
+  return frame;
+}
+
+// Register names for mips.
+static const char* const kRegisterNames[] = {
+   "$zero", "$at", "$v0", "$v1", "$a0", "$a1", "$a2", "$a3", "$to", "$t1",
+   "$t2",   "$t3", "$t4", "$t5", "$t6", "$t7", "$s0", "$s1", "$s2", "$s3",
+   "$s4",   "$s5", "$s6", "$s7", "$t8", "$t9", "$k0", "$k1", "$gp", "$sp",
+   "$fp",   "$ra", NULL
+  // TODO(gordanac): add float point save registers
+};
+
+StackFrameMIPS* StackwalkerMIPS::GetCallerByCFIFrameInfo(
+    const vector<StackFrame*>& frames,
+    CFIFrameInfo* cfi_frame_info) {
+  StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back());
+
+  unsigned long sp = 0, pc = 0;
+
+  // Populate a dictionary with the valid register values in last_frame.
+  CFIFrameInfo::RegisterValueMap<uint32_t> callee_registers;
+  // Use the STACK CFI data to recover the caller's register values.
+  CFIFrameInfo::RegisterValueMap<uint32_t> caller_registers;
+
+  for (int i = 0; kRegisterNames[i]; ++i) {
+    caller_registers[kRegisterNames[i]] = last_frame->context.iregs[i];
+    callee_registers[kRegisterNames[i]] = last_frame->context.iregs[i];
+  }
+
+  if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_,
+                                      &caller_registers))  {
+    return NULL;
+  }
+
+  CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator entry =
+      caller_registers.find(".cfa");
+
+  if (entry != caller_registers.end()) {
+    sp = entry->second;
+    caller_registers["$sp"] = entry->second;
+  }
+
+  entry = caller_registers.find(".ra");
+  if (entry != caller_registers.end()) {
+    caller_registers["$ra"] = entry->second;
+    pc = entry->second - 2 * sizeof(pc);
+  }
+  caller_registers["$pc"] = pc;
+  // Construct a new stack frame given the values the CFI recovered.
+  scoped_ptr<StackFrameMIPS> frame(new StackFrameMIPS());
+
+  for (int i = 0; kRegisterNames[i]; ++i) {
+    CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator caller_entry =
+        caller_registers.find(kRegisterNames[i]);
+
+    if (caller_entry != caller_registers.end()) {
+      // The value of this register is recovered; fill the context with the
+      // value from caller_registers.
+      frame->context.iregs[i] = caller_entry->second;
+      frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i);
+    } else if ((i >= INDEX_MIPS_REG_S0 && i <= INDEX_MIPS_REG_S7 ||
+                i > INDEX_MIPS_REG_GP && i < INDEX_MIPS_REG_RA) &&
+               (last_frame->context_validity &
+                StackFrameMIPS::RegisterValidFlag(i))) {
+      // If the STACK CFI data doesn't mention some callee-save register, and
+      // it is valid in the callee, assume the callee has not yet changed it.
+      // Calee-save registers according to the MIPS o32 ABI specification are:
+      // $s0 to $s7
+      // $sp, $s8
+      frame->context.iregs[i] = last_frame->context.iregs[i];
+      frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i);
+    }
+  }
+
+  frame->context.epc = caller_registers["$pc"];
+  frame->instruction = caller_registers["$pc"];
+  frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC;
+  
+  frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = caller_registers["$ra"];
+  frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA;
+
+  frame->trust = StackFrame::FRAME_TRUST_CFI;
+
+  return frame.release();
+}
+
+StackFrame* StackwalkerMIPS::GetCallerFrame(const CallStack* stack,
+                                            bool stack_scan_allowed) {
+  if (!memory_ || !stack) {
+    BPLOG(ERROR) << "Can't get caller frame without memory or stack";
+    return NULL;
+  }
+
+  const vector<StackFrame*>& frames = *stack->frames();
+  StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back());
+  scoped_ptr<StackFrameMIPS> new_frame;
+
+  // See if there is DWARF call frame information covering this address.
+  scoped_ptr<CFIFrameInfo> cfi_frame_info(
+    frame_symbolizer_->FindCFIFrameInfo(last_frame));
+  if (cfi_frame_info.get())
+    new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
+
+  // If caller frame is not found in CFI try analyzing the stack.
+  if (stack_scan_allowed && !new_frame.get()) {
+    new_frame.reset(GetCallerByStackScan(frames));
+  }
+
+  // If nothing worked, tell the caller.
+  if (!new_frame.get()) {
+    return NULL;
+  }
+
+  // Treat an instruction address of 0 as end-of-stack.
+  if (new_frame->context.epc == 0) {
+    return NULL;
+  }
+
+  // If the new stack pointer is at a lower address than the old, then
+  // that's clearly incorrect. Treat this as end-of-stack to enforce
+  // progress and avoid infinite loops.
+  if (new_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] <=
+      last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]) {
+    return NULL;
+  }
+  
+  return new_frame.release();
+}
+
+StackFrameMIPS* StackwalkerMIPS::GetCallerByStackScan(
+    const vector<StackFrame*>& frames) {
+  const uint32_t kMaxFrameStackSize = 1024;
+  const uint32_t kMinArgsOnStack = 4;
+
+  StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back());
+
+  uint32_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP];
+  uint32_t caller_pc, caller_sp, caller_fp;
+
+  // Return address cannot be obtained directly.
+  // Force stackwalking.
+
+  // We cannot use frame pointer to get the return address.
+  // We'll scan the stack for a
+  // return address. This can happen if last_frame is executing code
+  // for a module for which we don't have symbols.
+  int count = kMaxFrameStackSize / sizeof(caller_pc);
+
+  if (frames.size() > 1) {
+      // In case of mips32 ABI stack frame of a nonleaf function
+      // must have minimum stack frame assigned for 4 arguments (4 words).
+      // Move stack pointer for 4 words to avoid reporting non-existing frames
+      // for all frames except the topmost one.
+      // There is no way of knowing if topmost frame belongs to a leaf or
+      // a nonleaf function.
+      last_sp +=  kMinArgsOnStack * sizeof(caller_pc);
+      // Adjust 'count' so that return address is scanned only in limits 
+      // of one stack frame.
+      count -= kMinArgsOnStack;
+  }
+
+  do {
+    // Scanning for return address from stack pointer of the last frame.
+    if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc, count)) {
+      // If we can't find an instruction pointer even with stack scanning,
+      // give up.
+      BPLOG(ERROR) << " ScanForReturnAddress failed ";
+      return NULL;
+    }
+    // Get $fp stored in the stack frame.
+    if (!memory_->GetMemoryAtAddress(caller_sp - sizeof(caller_pc),
+                                     &caller_fp)) {
+      BPLOG(INFO) << " GetMemoryAtAddress for fp failed " ;
+      return NULL;
+    }
+
+    count = count - (caller_sp - last_sp) / sizeof(caller_pc);
+    // Now scan the next address in the stack.
+    last_sp = caller_sp + sizeof(caller_pc);
+  } while ((caller_fp - caller_sp >= kMaxFrameStackSize) && count > 0);
+
+  if (!count) {
+    BPLOG(INFO) << " No frame found " ;
+    return NULL;
+  }
+
+  // ScanForReturnAddress found a reasonable return address. Advance
+  // $sp to the location above the one where the return address was
+  // found. 
+  caller_sp += sizeof(caller_pc);
+  // caller_pc is actually containing $ra value;
+  // $pc is two instructions before $ra,
+  // so the caller_pc needs to be decremented accordingly.
+  caller_pc -= 2 * sizeof(caller_pc);
+
+
+  // Create a new stack frame (ownership will be transferred to the caller)
+  // and fill it in.
+  StackFrameMIPS* frame = new StackFrameMIPS();
+  frame->trust = StackFrame::FRAME_TRUST_SCAN;
+  frame->context = last_frame->context;
+  frame->context.epc = caller_pc;
+  frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC;
+  frame->instruction = caller_pc;
+
+  frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] = caller_sp;
+  frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_SP;
+  frame->context.iregs[MD_CONTEXT_MIPS_REG_FP] = caller_fp;
+  frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_FP;
+
+  frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] =
+      caller_pc + 2 * sizeof(caller_pc);
+  frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA;
+
+  return frame;
+}
+
+}  // namespace google_breakpad
+
diff --git a/src/processor/stackwalker_mips.h b/src/processor/stackwalker_mips.h
new file mode 100644
index 00000000..5f97791f
--- /dev/null
+++ b/src/processor/stackwalker_mips.h
@@ -0,0 +1,85 @@
+// Copyright (c) 2013 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// stackwalker_mips.h: MIPS-specific stackwalker.
+//
+// Provides stack frames given MIPS register context and a memory region
+// corresponding to a MIPSstack.
+//
+// Author: Tata Elxsi
+
+#ifndef PROCESSOR_STACKWALKER_MIPS_H__
+#define PROCESSOR_STACKWALKER_MIPS_H__
+
+#include "google_breakpad/common/breakpad_types.h"
+#include "google_breakpad/common/minidump_format.h"
+#include "google_breakpad/processor/stackwalker.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "processor/cfi_frame_info.h"
+
+namespace google_breakpad {
+
+class CodeModules;
+
+class StackwalkerMIPS : public Stackwalker {
+ public:
+  // Context is a MIPS context object that gives access to mips-specific
+  // register state corresponding to the innermost called frame to be
+  // included in the stack.  The other arguments are passed directly
+  // through to the base Stackwalker constructor.
+  StackwalkerMIPS(const SystemInfo* system_info,
+                  const MDRawContextMIPS* context,
+                  MemoryRegion* memory,
+                  const CodeModules* modules,
+                  StackFrameSymbolizer* frame_symbolizer);
+
+ private:
+  // Implementation of Stackwalker, using mips context and stack conventions.
+  virtual StackFrame* GetContextFrame();
+  virtual StackFrame* GetCallerFrame(const CallStack* stack,
+                                     bool stack_scan_allowed);
+
+  // Use cfi_frame_info (derived from STACK CFI records) to construct
+  // the frame that called frames.back(). The caller takes ownership
+  // of the returned frame. Return NULL on failure.
+  StackFrameMIPS* GetCallerByCFIFrameInfo(const vector<StackFrame*>& frames,
+                                          CFIFrameInfo* cfi_frame_info);
+
+  // Scan the stack for plausible return address and frame pointer pair. 
+  // The caller takes ownership of the returned frame. Return NULL on failure.
+  StackFrameMIPS* GetCallerByStackScan(const vector<StackFrame*>& frames);
+
+  // Stores the CPU context corresponding to the innermost stack frame to
+  // be returned by GetContextFrame.
+  const MDRawContextMIPS* context_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // PROCESSOR_STACKWALKER_MIPS_H__
diff --git a/src/processor/stackwalker_mips_unittest.cc b/src/processor/stackwalker_mips_unittest.cc
new file mode 100644
index 00000000..ed4be4f5
--- /dev/null
+++ b/src/processor/stackwalker_mips_unittest.cc
@@ -0,0 +1,697 @@
+// Copyright (c) 2013, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Original author: Gordana Cmiljanovic <gordana.cmiljanovic@imgtec.com>
+
+// stackwalker_mips_unittest.cc: Unit tests for StackwalkerMIPS class.
+
+#include <string.h>
+#include <string>
+#include <vector>
+
+#include "breakpad_googletest_includes.h"
+#include "common/test_assembler.h"
+#include "common/using_std_string.h"
+#include "google_breakpad/common/minidump_format.h"
+#include "google_breakpad/processor/basic_source_line_resolver.h"
+#include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/code_module.h"
+#include "google_breakpad/processor/source_line_resolver_interface.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "processor/stackwalker_unittest_utils.h"
+#include "processor/stackwalker_mips.h"
+#include "processor/windows_frame_info.h"
+
+using google_breakpad::BasicSourceLineResolver;
+using google_breakpad::CallStack;
+using google_breakpad::CodeModule;
+using google_breakpad::StackFrameSymbolizer;
+using google_breakpad::StackFrame;
+using google_breakpad::StackFrameMIPS;
+using google_breakpad::Stackwalker;
+using google_breakpad::StackwalkerMIPS;
+using google_breakpad::SystemInfo;
+using google_breakpad::WindowsFrameInfo;
+using google_breakpad::test_assembler::kLittleEndian;
+using google_breakpad::test_assembler::Label;
+using google_breakpad::test_assembler::Section;
+using std::vector;
+using testing::_;
+using testing::AnyNumber;
+using testing::Return;
+using testing::SetArgumentPointee;
+using testing::Test;
+
+class StackwalkerMIPSFixture {
+ public:
+  StackwalkerMIPSFixture()
+    : stack_section(kLittleEndian),
+      // Give the two modules reasonable standard locations and names
+      // for tests to play with.
+      module1(0x00400000, 0x10000, "module1", "version1"),
+      module2(0x00500000, 0x10000, "module2", "version2") {
+    // Identify the system as a Linux system.
+    system_info.os = "Linux";
+    system_info.os_short = "linux";
+    system_info.os_version = "Observant Opossum";  // Jealous Jellyfish
+    system_info.cpu = "mips";
+    system_info.cpu_info = "";
+
+    // Put distinctive values in the raw CPU context.
+    BrandContext(&raw_context);
+
+    // Create some modules with some stock debugging information.
+    modules.Add(&module1);
+    modules.Add(&module2);
+
+    // By default, none of the modules have symbol info; call
+    // SetModuleSymbols to override this.
+    EXPECT_CALL(supplier, GetCStringSymbolData(_, _, _, _, _))
+      .WillRepeatedly(Return(MockSymbolSupplier::NOT_FOUND));
+
+    // Avoid GMOCK WARNING "Uninteresting mock function call - returning
+    // directly" for FreeSymbolData().
+    EXPECT_CALL(supplier, FreeSymbolData(_)).Times(AnyNumber());
+
+    // Reset max_frames_scanned since it's static.
+    Stackwalker::set_max_frames_scanned(1024);    
+  }
+
+  // Set the Breakpad symbol information that supplier should return for
+  // MODULE to INFO.
+  void SetModuleSymbols(MockCodeModule* module, const string& info) {
+    size_t buffer_size;
+    char* buffer = supplier.CopySymbolDataAndOwnTheCopy(info, &buffer_size);
+    EXPECT_CALL(supplier, GetCStringSymbolData(module, &system_info, _, _, _))
+      .WillRepeatedly(DoAll(SetArgumentPointee<3>(buffer),
+                            SetArgumentPointee<4>(buffer_size),
+                            Return(MockSymbolSupplier::FOUND)));
+  }
+
+  // Populate stack_region with the contents of stack_section. Use
+  // stack_section.start() as the region's starting address.
+  void RegionFromSection() {
+    string contents;
+    ASSERT_TRUE(stack_section.GetContents(&contents));
+    stack_region.Init(stack_section.start().Value(), contents);
+  }
+
+  // Fill RAW_CONTEXT with pseudo-random data, for round-trip checking.
+  void BrandContext(MDRawContextMIPS* raw_context) {
+    uint8_t x = 173;
+    for (size_t i = 0; i < sizeof(*raw_context); ++i)
+      reinterpret_cast<uint8_t*>(raw_context)[i] = (x += 17);
+  }
+
+  SystemInfo system_info;
+  MDRawContextMIPS raw_context;
+  Section stack_section;
+  MockMemoryRegion stack_region;
+  MockCodeModule module1;
+  MockCodeModule module2;
+  MockCodeModules modules;
+  MockSymbolSupplier supplier;
+  BasicSourceLineResolver resolver;
+  CallStack call_stack;
+  const vector<StackFrame*>* frames;
+};
+
+class SanityCheck: public StackwalkerMIPSFixture, public Test { };
+
+TEST_F(SanityCheck, NoResolver) {
+  stack_section.start() = 0x80000000;
+  stack_section.D32(0).D32(0x0);
+  RegionFromSection();
+  raw_context.epc = 0x00400020;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = 0x80000000;
+
+  StackFrameSymbolizer frame_symbolizer(NULL, NULL);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                        &frame_symbolizer);
+  // This should succeed, even without a resolver or supplier.
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(1U, modules_without_symbols.size());
+  ASSERT_EQ("module1", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(1U, frames->size());
+  StackFrameMIPS* frame = static_cast<StackFrameMIPS*>(frames->at(0));
+  // Check that the values from the original raw context made it
+  // through to the context in the stack frame.
+  EXPECT_EQ(0, memcmp(&raw_context, &frame->context, sizeof(raw_context)));
+}
+
+class GetContextFrame: public StackwalkerMIPSFixture, public Test { };
+
+TEST_F(GetContextFrame, Simple) {
+  stack_section.start() = 0x80000000;
+  stack_section.D32(0).D32(0x0);
+  RegionFromSection();
+  raw_context.epc = 0x00400020;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = 0x80000000;
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(1U, modules_without_symbols.size());
+  ASSERT_EQ("module1", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  StackFrameMIPS* frame = static_cast<StackFrameMIPS*>(frames->at(0));
+  // Check that the values from the original raw context made it
+  // through to the context in the stack frame.
+  EXPECT_EQ(0, memcmp(&raw_context, &frame->context, sizeof(raw_context)));
+}
+
+// The stackwalker should be able to produce the context frame even
+// without stack memory present.
+TEST_F(GetContextFrame, NoStackMemory) {
+  raw_context.epc = 0x00400020;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = 0x80000000;
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, NULL, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(1U, modules_without_symbols.size());
+  ASSERT_EQ("module1", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  StackFrameMIPS* frame = static_cast<StackFrameMIPS*>(frames->at(0));
+  // Check that the values from the original raw context made it
+  // through to the context in the stack frame.
+  EXPECT_EQ(0, memcmp(&raw_context, &frame->context, sizeof(raw_context)));
+}
+
+class GetCallerFrame: public StackwalkerMIPSFixture, public Test { };
+
+TEST_F(GetCallerFrame, ScanWithoutSymbols) {
+  // When the stack walker resorts to scanning the stack,
+  // only addresses located within loaded modules are
+  // considered valid return addresses.
+  // Force scanning through three frames to ensure that the
+  // stack pointer is set properly in scan-recovered frames.
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x00400100;
+  uint32_t return_address2 = 0x00400900;
+  Label frame1_sp, frame2_sp;
+  stack_section
+    // frame 0
+    .Append(16, 0)                      // space
+
+    .D32(0x00490000)                    // junk that's not
+    .D32(0x00600000)                    // a return address
+
+    .D32(frame1_sp)                     // stack pointer
+    .D32(return_address1)               // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(16, 0)                      // space
+
+    .D32(0xF0000000)                    // more junk
+    .D32(0x0000000D)
+
+    .D32(frame2_sp)                     // stack pointer
+    .D32(return_address2)               // actual return address
+    // frame 2
+    .Mark(&frame2_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.epc = 0x00405510;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = stack_section.start().Value();
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_RA] = return_address1;
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(1U, modules_without_symbols.size());
+  ASSERT_EQ("module1", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(3U, frames->size());
+
+  StackFrameMIPS* frame0 = static_cast<StackFrameMIPS*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameMIPS::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+
+  StackFrameMIPS* frame1 = static_cast<StackFrameMIPS*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame1->trust);
+  ASSERT_EQ((StackFrameMIPS::CONTEXT_VALID_PC |
+             StackFrameMIPS::CONTEXT_VALID_SP |
+             StackFrameMIPS::CONTEXT_VALID_FP |
+             StackFrameMIPS::CONTEXT_VALID_RA),
+            frame1->context_validity);
+  EXPECT_EQ(return_address1 - 2 * sizeof(return_address1), frame1->context.epc);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_MIPS_REG_SP]);
+
+  StackFrameMIPS* frame2 = static_cast<StackFrameMIPS*>(frames->at(2));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame2->trust);
+  ASSERT_EQ((StackFrameMIPS::CONTEXT_VALID_PC |
+             StackFrameMIPS::CONTEXT_VALID_SP |
+             StackFrameMIPS::CONTEXT_VALID_FP |
+             StackFrameMIPS::CONTEXT_VALID_RA),
+            frame2->context_validity);
+  EXPECT_EQ(return_address2 - 2 * sizeof(return_address2), frame2->context.epc);
+  EXPECT_EQ(frame2_sp.Value(), frame2->context.iregs[MD_CONTEXT_MIPS_REG_SP]);
+}
+
+TEST_F(GetCallerFrame, ScanWithFunctionSymbols) {
+  // During stack scanning, if a potential return address
+  // is located within a loaded module that has symbols,
+  // it is only considered a valid return address if it
+  // lies within a function's bounds.
+  stack_section.start() = 0x80000000;
+  uint32_t return_address = 0x00500200;
+  Label frame1_sp;
+  stack_section
+    // frame 0
+    .Append(16, 0)                      // space
+
+    .D32(0x00490000)                    // junk that's not
+    .D32(0x00600000)                    // a return address
+    
+    .D32(0x00401000)                    // a couple of plausible addresses
+    .D32(0x0050F000)                    // that are not within functions
+
+    .D32(frame1_sp)                     // stack pointer
+    .D32(return_address)                // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.epc = 0x00400200;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = stack_section.start().Value();
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_RA] = return_address;
+
+  SetModuleSymbols(&module1,
+                   // The youngest frame's function.
+                   "FUNC 100 400 10 monotreme\n");
+  SetModuleSymbols(&module2,
+                   // The calling frame's function.
+                   "FUNC 100 400 10 marsupial\n");
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(0U, modules_without_symbols.size());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameMIPS* frame0 = static_cast<StackFrameMIPS*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameMIPS::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+  EXPECT_EQ("monotreme", frame0->function_name);
+  EXPECT_EQ(0x00400100U, frame0->function_base);
+
+  StackFrameMIPS* frame1 = static_cast<StackFrameMIPS*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame1->trust);
+  ASSERT_EQ((StackFrameMIPS::CONTEXT_VALID_PC |
+             StackFrameMIPS::CONTEXT_VALID_SP |
+             StackFrameMIPS::CONTEXT_VALID_FP |
+             StackFrameMIPS::CONTEXT_VALID_RA),
+            frame1->context_validity);
+  EXPECT_EQ(return_address - 2 * sizeof(return_address), frame1->context.epc);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_MIPS_REG_SP]);
+  EXPECT_EQ("marsupial", frame1->function_name);
+  EXPECT_EQ(0x00500100U, frame1->function_base);
+}
+
+TEST_F(GetCallerFrame, CheckStackFrameSizeLimit) {
+  // If the stackwalker resorts to stack scanning, it will scan only
+  // 1024 bytes of stack which correspondes to maximum size of stack frame.
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x00500100;
+  uint32_t return_address2 = 0x00500900;
+  Label frame1_sp, frame2_sp;
+  stack_section
+    // frame 0
+    .Append(32, 0)                      // space
+
+    .D32(0x00490000)                    // junk that's not
+    .D32(0x00600000)                    // a return address
+
+    .Append(96, 0)                      // more space
+
+    .D32(frame1_sp)                     // stack pointer
+    .D32(return_address1)               // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(128 * 4, 0)                 // space
+
+    .D32(0x00F00000)                    // more junk
+    .D32(0x0000000D)
+
+    .Append(128 * 4, 0)                 // more space
+
+    .D32(frame2_sp)                     // stack pointer
+    .D32(return_address2)               // actual return address
+                                        // (won't be found)
+    // frame 2
+    .Mark(&frame2_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.epc = 0x00405510;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = stack_section.start().Value();
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_RA] = return_address1;
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(2U, modules_without_symbols.size());
+  ASSERT_EQ("module1", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ("module2", modules_without_symbols[1]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameMIPS* frame0 = static_cast<StackFrameMIPS*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameMIPS::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+
+  StackFrameMIPS* frame1 = static_cast<StackFrameMIPS*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame1->trust);
+  ASSERT_EQ((StackFrameMIPS::CONTEXT_VALID_PC |
+             StackFrameMIPS::CONTEXT_VALID_SP |
+             StackFrameMIPS::CONTEXT_VALID_FP |
+             StackFrameMIPS::CONTEXT_VALID_RA),
+            frame1->context_validity);
+  EXPECT_EQ(return_address1 - 2 * sizeof(return_address1), frame1->context.epc);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_MIPS_REG_SP]);
+}
+
+// Test that set_max_frames_scanned prevents using stack scanning
+// to find caller frames.
+TEST_F(GetCallerFrame, ScanningNotAllowed) {
+  // When the stack walker resorts to scanning the stack,
+  // only fixed number of frames are allowed to be scanned out from stack
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x00500100;
+  uint32_t return_address2 = 0x00500900;
+  Label frame1_sp, frame2_sp;
+  stack_section
+    // frame 0
+    .Append(32, 0)                      // space
+
+    .D32(0x00490000)                    // junk that's not
+    .D32(0x00600000)                    // a return address
+
+    .Append(96, 0)                      // more space
+
+    .D32(frame1_sp)                     // stack pointer
+    .D32(return_address1)               // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(128 * 4, 0)                 // space
+
+    .D32(0x00F00000)                    // more junk
+    .D32(0x0000000D)
+
+    .Append(128 * 4, 0)                 // more space
+
+    .D32(frame2_sp)                     // stack pointer
+    .D32(return_address2)               // actual return address
+                                        // (won't be found)
+    // frame 2
+    .Mark(&frame2_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.epc = 0x00405510;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = stack_section.start().Value();
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_RA] = return_address1;
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  Stackwalker::set_max_frames_scanned(0);
+                         
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(1U, modules_without_symbols.size());
+  ASSERT_EQ("module1", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(1U, frames->size());
+
+  StackFrameMIPS* frame0 = static_cast<StackFrameMIPS*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameMIPS::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+}
+
+struct CFIFixture: public StackwalkerMIPSFixture {
+  CFIFixture() {
+    // Provide some STACK CFI records;
+    SetModuleSymbols(&module1,
+                     // The youngest frame's function.
+                     "FUNC 4000 1000 0 enchiridion\n"
+                     // Initially, nothing has been pushed on the stack,
+                     // and the return address is still in the $ra register.
+                     "STACK CFI INIT 4000 1000 .cfa: $sp 0 + .ra: $ra\n"
+                     // Move stack pointer.
+                     "STACK CFI 4004 .cfa: $sp 32 +\n"
+                     // store $fp and ra
+                     "STACK CFI 4008 $fp: .cfa -8 + ^ .ra: .cfa -4 + ^\n"
+                     // restore $fp
+                     "STACK CFI 400c .cfa: $fp 32 +\n"
+                     // restore $sp
+                     "STACK CFI 4018 .cfa: $sp 32 +\n"
+
+                     "STACK CFI 4020 $fp: $fp .cfa: $sp 0 + .ra: .ra\n"
+
+                     // The calling function.
+                     "FUNC 5000 1000 0 epictetus\n"
+                     // Initially, nothing has been pushed on the stack,
+                     // and the return address is still in the $ra register.
+                     "STACK CFI INIT 5000 1000 .cfa: $sp .ra: $ra\n"
+                     // Mark it as end of stack.
+                     "STACK CFI INIT 5000 8 .cfa: $sp 0 + .ra: $ra\n"
+
+                     // A function whose CFI makes the stack pointer
+                     // go backwards.
+                     "FUNC 6000 1000 20 palinal\n"
+                     "STACK CFI INIT 6000 1000 .cfa: $sp 4 - .ra: $ra\n"
+
+                     // A function with CFI expressions that can't be
+                     // evaluated.
+                     "FUNC 7000 1000 20 rhetorical\n"
+                     "STACK CFI INIT 7000 1000 .cfa: moot .ra: ambiguous\n"
+                   );
+
+    // Provide some distinctive values for the caller's registers.
+    expected.epc = 0x00405508;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S0] = 0x0;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S1] = 0x1;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S2] = 0x2;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S3] = 0x3;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S4] = 0x4;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S5] = 0x5;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S6] = 0x6;
+    expected.iregs[MD_CONTEXT_MIPS_REG_S7] = 0x7;
+    expected.iregs[MD_CONTEXT_MIPS_REG_SP] = 0x80000000;
+    expected.iregs[MD_CONTEXT_MIPS_REG_FP] = 0x80000000;
+    expected.iregs[MD_CONTEXT_MIPS_REG_RA] = 0x00405510;
+
+    // Expect CFI to recover all callee-save registers. Since CFI is the
+    // only stack frame construction technique we have, aside from the
+    // context frame itself, there's no way for us to have a set of valid
+    // registers smaller than this.
+    expected_validity = (StackFrameMIPS::CONTEXT_VALID_PC |
+                         StackFrameMIPS::CONTEXT_VALID_S0 |
+                         StackFrameMIPS::CONTEXT_VALID_S1 |
+                         StackFrameMIPS::CONTEXT_VALID_S2 |
+                         StackFrameMIPS::CONTEXT_VALID_S3 |
+                         StackFrameMIPS::CONTEXT_VALID_S4 |
+                         StackFrameMIPS::CONTEXT_VALID_S5 |
+                         StackFrameMIPS::CONTEXT_VALID_S6 |
+                         StackFrameMIPS::CONTEXT_VALID_S7 |
+                         StackFrameMIPS::CONTEXT_VALID_SP |
+                         StackFrameMIPS::CONTEXT_VALID_FP |
+                         StackFrameMIPS::CONTEXT_VALID_RA);
+
+    // By default, context frames provide all registers, as normal.
+    context_frame_validity = StackFrameMIPS::CONTEXT_VALID_ALL;
+
+    // By default, registers are unchanged.
+    raw_context = expected;
+  }
+
+  // Walk the stack, using stack_section as the contents of the stack
+  // and raw_context as the current register values. (Set the stack
+  // pointer to the stack's starting address.) Expect two stack
+  // frames; in the older frame, expect the callee-saves registers to
+  // have values matching those in 'expected'.
+  void CheckWalk() {
+    RegionFromSection();
+    raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = stack_section.start().Value();
+
+    StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+    StackwalkerMIPS walker(&system_info, &raw_context, &stack_region,
+                           &modules, &frame_symbolizer);
+    vector<const CodeModule*> modules_without_symbols;
+    vector<const CodeModule*> modules_with_corrupt_symbols;
+    ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                            &modules_with_corrupt_symbols));
+    ASSERT_EQ(0U, modules_without_symbols.size());
+    ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+    frames = call_stack.frames();
+    ASSERT_EQ(2U, frames->size());
+
+    StackFrameMIPS* frame0 = static_cast<StackFrameMIPS*>(frames->at(0));
+    EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+    ASSERT_EQ(StackFrameMIPS::CONTEXT_VALID_ALL, frame0->context_validity);
+    EXPECT_EQ("enchiridion", frame0->function_name);
+    EXPECT_EQ(0x00404000U, frame0->function_base);
+
+    StackFrameMIPS* frame1 = static_cast<StackFrameMIPS*>(frames->at(1));
+    EXPECT_EQ(StackFrame::FRAME_TRUST_CFI, frame1->trust);
+    ASSERT_EQ(expected_validity, frame1->context_validity);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S0],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S0]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S1],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S1]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S2],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S2]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S3],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S3]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S4],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S4]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S5],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S5]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S6],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S6]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_S7],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_S7]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_FP],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_FP]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_RA],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_RA]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_MIPS_REG_SP],
+              frame1->context.iregs[MD_CONTEXT_MIPS_REG_SP]);
+    EXPECT_EQ(expected.epc, frame1->context.epc);
+    EXPECT_EQ(expected.epc, frame1->instruction);
+    EXPECT_EQ("epictetus", frame1->function_name);
+    EXPECT_EQ(0x00405000U, frame1->function_base);    
+  }
+
+  // The values we expect to find for the caller's registers.
+  MDRawContextMIPS expected;
+
+  // The validity mask for expected.
+  int expected_validity;
+
+  // The validity mask to impose on the context frame.
+  int context_frame_validity;
+};
+
+class CFI: public CFIFixture, public Test { };
+
+// TODO(gordanac): add CFI tests
+
+TEST_F(CFI, At4004) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_MIPS_REG_SP];
+  stack_section
+    // frame0
+    .Append(24, 0)               // space
+    .D32(frame1_sp)              // stack pointer
+    .D32(0x00405510)             // return address
+    .Mark(&frame1_sp);           // This effectively sets stack_section.start().
+  raw_context.epc = 0x00404004;
+  CheckWalk();
+}
+
+// Check that we reject rules that would cause the stack pointer to
+// move in the wrong direction.
+TEST_F(CFI, RejectBackwards) {
+  raw_context.epc = 0x40005000;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = 0x80000000;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_RA] = 0x00405510;
+  
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(0U, modules_without_symbols.size());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(1U, frames->size());
+}
+
+// Check that we reject rules whose expressions' evaluation fails.
+TEST_F(CFI, RejectBadExpressions) {
+  raw_context.epc = 0x00407000;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_SP] = 0x80000000;
+  raw_context.iregs[MD_CONTEXT_MIPS_REG_RA] = 0x00405510;
+  
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerMIPS walker(&system_info, &raw_context, &stack_region, &modules,
+                         &frame_symbolizer);
+  vector<const CodeModule*> modules_without_symbols;
+  vector<const CodeModule*> modules_with_corrupt_symbols;
+  ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+                          &modules_with_corrupt_symbols));
+  ASSERT_EQ(0U, modules_without_symbols.size());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(1U, frames->size());
+}
diff --git a/src/processor/synth_minidump.cc b/src/processor/synth_minidump.cc
index 0940a357..2cfbb088 100644
--- a/src/processor/synth_minidump.cc
+++ b/src/processor/synth_minidump.cc
@@ -195,6 +195,42 @@ Context::Context(const Dump &dump, const MDRawContextARM &context)
   assert(Size() == sizeof(MDRawContextARM));
 }
 
+Context::Context(const Dump &dump, const MDRawContextMIPS &context)
+    : Section(dump) {
+  // The caller should have properly set the CPU type flag.
+  assert(context.context_flags & MD_CONTEXT_MIPS);
+  D32(context.context_flags);
+  D32(context._pad0);
+
+  for (int i = 0; i < MD_CONTEXT_MIPS_GPR_COUNT; ++i)
+    D64(context.iregs[i]);
+
+  D64(context.mdhi);
+  D64(context.mdlo);
+
+  for (int i = 0; i < MD_CONTEXT_MIPS_DSP_COUNT; ++i)
+    D32(context.hi[i]);
+
+  for (int i = 0; i < MD_CONTEXT_MIPS_DSP_COUNT; ++i)
+    D32(context.lo[i]);
+
+  D32(context.dsp_control);
+  D32(context._pad1);
+
+  D64(context.epc);
+  D64(context.badvaddr);
+  D32(context.status);
+  D32(context.cause);
+
+  for (int i = 0; i < MD_FLOATINGSAVEAREA_MIPS_FPR_COUNT; ++i)
+    D64(context.float_save.regs[i]);
+
+  D32(context.float_save.fpcsr);
+  D32(context.float_save.fir);
+
+  assert(Size() == sizeof(MDRawContextMIPS));
+}
+
 Thread::Thread(const Dump &dump,
                uint32_t thread_id, const Memory &stack, const Context &context,
                uint32_t suspend_count, uint32_t priority_class,
diff --git a/src/processor/synth_minidump.h b/src/processor/synth_minidump.h
index fbc1e29b..8dac8784 100644
--- a/src/processor/synth_minidump.h
+++ b/src/processor/synth_minidump.h
@@ -228,6 +228,7 @@ class Context: public Section {
   // Create a context belonging to DUMP whose contents are a copy of CONTEXT.
   Context(const Dump &dump, const MDRawContextX86 &context);
   Context(const Dump &dump, const MDRawContextARM &context);
+  Context(const Dump &dump, const MDRawContextMIPS &context);
   // Add an empty context to the dump.
   Context(const Dump &dump) : Section(dump) {}
   // Add constructors for other architectures here. Remember to byteswap.