Breakpad processor: Unit tests for StackwalkerX86.

Issue 53001 (http://breakpad.appspot.com/53001) defines the
TestAssembler classes; those, along with a new set of mock classes
defined in stackwalker_unittest_utils.h, make it possible for us to
actually do proper unit testing of a stack walker. These tests get us
full code coverage for stackwalker_x86.cc.

a=jimblandy, r=mmentovai


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@548 4c0a9323-5329-0410-9bdc-e9ce6186880e

2 files changed, 879 insertions, 0 deletions

diff --git a/src/processor/stackwalker_unittest_utils.h b/src/processor/stackwalker_unittest_utils.h
new file mode 100644
index 00000000..a7bff3e8
--- /dev/null
+++ b/src/processor/stackwalker_unittest_utils.h
@@ -0,0 +1,175 @@
+// -*- mode: C++ -*-
+
+// Copyright (c) 2010, 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: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+
+// Mock classes for writing stackwalker tests, shared amongst architectures.
+
+#ifndef PROCESSOR_STACKWALKER_UNITTEST_UTILS_H_
+#define PROCESSOR_STACKWALKER_UNITTEST_UTILS_H_
+
+#include <stdlib.h>
+#include <string>
+#include <vector>
+
+#include "google_breakpad/common/breakpad_types.h"
+#include "google_breakpad/processor/code_module.h"
+#include "google_breakpad/processor/code_modules.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/symbol_supplier.h"
+#include "google_breakpad/processor/system_info.h"
+
+class MockMemoryRegion: public google_breakpad::MemoryRegion {
+ public:
+  MockMemoryRegion(): base_address_(0) { }
+
+  // Set this region's address and contents. If we have placed an
+  // instance of this class in a test fixture class, individual tests
+  // can use this to provide the region's contents.
+  void Init(u_int64_t base_address, const std::string &contents) {
+    base_address_ = base_address;
+    contents_ = contents;
+  }
+
+  u_int64_t GetBase() const { return base_address_; }
+  u_int32_t GetSize() const { return contents_.size(); }
+
+  bool GetMemoryAtAddress(u_int64_t address, u_int8_t  *value) const {
+    return GetMemoryLittleEndian(address, value);
+  }
+  bool GetMemoryAtAddress(u_int64_t address, u_int16_t *value) const {
+    return GetMemoryLittleEndian(address, value);
+  }
+  bool GetMemoryAtAddress(u_int64_t address, u_int32_t *value) const {
+    return GetMemoryLittleEndian(address, value);
+  }
+  bool GetMemoryAtAddress(u_int64_t address, u_int64_t *value) const {
+    return GetMemoryLittleEndian(address, value);
+  }
+
+ private:
+  // Fetch a little-endian value from ADDRESS in contents_ whose size
+  // is BYTES, and store it in *VALUE. Return true on success.
+  template<typename ValueType>
+  bool GetMemoryLittleEndian(u_int64_t address, ValueType *value) const {
+    if (address < base_address_ ||
+        address - base_address_ + sizeof(ValueType) > contents_.size())
+      return false;
+    ValueType v = 0;
+    int start = address - base_address_;
+    // The loop condition is odd, but it's correct for size_t.
+    for (size_t i = sizeof(ValueType) - 1; i < sizeof(ValueType); i--)
+      v = (v << 8) | static_cast<unsigned char>(contents_[start + i]);
+    *value = v;
+    return true;
+  }
+
+  u_int64_t base_address_;
+  std::string contents_;
+};
+
+class MockCodeModule: public google_breakpad::CodeModule {
+ public:
+  MockCodeModule(u_int64_t base_address, u_int64_t size,
+                 const std::string &code_file, const std::string &version)
+      : base_address_(base_address), size_(size), code_file_(code_file) { }
+
+  u_int64_t base_address()       const { return base_address_; }
+  u_int64_t size()               const { return size_; }
+  std::string code_file()        const { return code_file_; }
+  std::string code_identifier()  const { return code_file_; }
+  std::string debug_file()       const { return code_file_; }
+  std::string debug_identifier() const { return code_file_; }
+  std::string version()          const { return version_; }
+  const google_breakpad::CodeModule *Copy() const {
+    abort(); // Tests won't use this.
+  }
+
+ private:
+  u_int64_t base_address_;
+  u_int64_t size_;
+  std::string code_file_;
+  std::string version_;
+};
+
+class MockCodeModules: public google_breakpad::CodeModules {
+ public:  
+  typedef google_breakpad::CodeModule CodeModule;
+  typedef google_breakpad::CodeModules CodeModules;
+
+  void Add(const MockCodeModule *module) { 
+    modules_.push_back(module);
+  }
+
+  unsigned int module_count() const { return modules_.size(); }
+
+  const CodeModule *GetModuleForAddress(u_int64_t address) const {
+    for (ModuleVector::const_iterator i = modules_.begin();
+         i != modules_.end(); i++) {
+      const MockCodeModule *module = *i;
+      if (module->base_address() <= address &&
+          address - module->base_address() < module->size())
+        return module;
+    }
+    return NULL;
+  };
+
+  const CodeModule *GetMainModule() const { return modules_[0]; }
+
+  const CodeModule *GetModuleAtSequence(unsigned int sequence) const {
+    return modules_.at(sequence);
+  }
+
+  const CodeModule *GetModuleAtIndex(unsigned int index) const {
+    return modules_.at(index);
+  }
+
+  const CodeModules *Copy() const { abort(); } // Tests won't use this.
+
+ private:  
+  typedef std::vector<const MockCodeModule *> ModuleVector;
+  ModuleVector modules_;
+};
+
+class MockSymbolSupplier: public google_breakpad::SymbolSupplier {
+ public:
+  typedef google_breakpad::CodeModule CodeModule;
+  typedef google_breakpad::SystemInfo SystemInfo;
+  MOCK_METHOD3(GetSymbolFile, SymbolResult(const CodeModule *module,
+                                           const SystemInfo *system_info,
+                                           std::string *symbol_file));
+  MOCK_METHOD4(GetSymbolFile, SymbolResult(const CodeModule *module,
+                                           const SystemInfo *system_info,
+                                           std::string *symbol_file,
+                                           std::string *symbol_data));
+};
+
+#endif // PROCESSOR_STACKWALKER_UNITTEST_UTILS_H_
diff --git a/src/processor/stackwalker_x86_unittest.cc b/src/processor/stackwalker_x86_unittest.cc
new file mode 100644
index 00000000..5381c482
--- /dev/null
+++ b/src/processor/stackwalker_x86_unittest.cc
@@ -0,0 +1,704 @@
+// Copyright (c) 2010, 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: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+
+// stackwalker_x86_unittest.cc: Unit tests for StackwalkerX86 class.
+
+#include <string>
+#include <vector>
+
+#include "breakpad_googletest_includes.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/source_line_resolver_interface.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "processor/stackwalker_unittest_utils.h"
+#include "processor/stackwalker_x86.h"
+#include "processor/test_assembler.h"
+#include "processor/windows_frame_info.h"
+
+using google_breakpad::BasicSourceLineResolver;
+using google_breakpad::CallStack;
+using google_breakpad::StackFrame;
+using google_breakpad::StackFrameX86;
+using google_breakpad::StackwalkerX86;
+using google_breakpad::SystemInfo;
+using google_breakpad::WindowsFrameInfo;
+using google_breakpad::TestAssembler::kLittleEndian;
+using google_breakpad::TestAssembler::Label;
+using google_breakpad::TestAssembler::Section;
+using std::string;
+using std::vector;
+using testing::_;
+using testing::Return;
+using testing::SetArgumentPointee;
+using testing::Test;
+
+class StackwalkerX86Fixture {
+ public:
+  StackwalkerX86Fixture()
+    : stack_section(kLittleEndian),
+      // Give the two modules reasonable standard locations and names
+      // for tests to play with.
+      module1(0x40000000, 0x10000, "module1", "version1"),
+      module2(0x50000000, 0x10000, "module2", "version2") {
+    // Identify the system as a Linux system.
+    system_info.os = "Linux";
+    system_info.os_short = "linux";
+    system_info.os_version = "Salacious Skink";
+    system_info.cpu = "x86";
+    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, GetSymbolFile(_, _, _, _))
+      .WillRepeatedly(Return(MockSymbolSupplier::NOT_FOUND));
+  }
+
+  // Set the Breakpad symbol information that supplier should return for
+  // MODULE to INFO.
+  void SetModuleSymbols(MockCodeModule *module, const string &info) {
+    EXPECT_CALL(supplier, GetSymbolFile(module, &system_info, _, _))
+      .WillRepeatedly(DoAll(SetArgumentPointee<3>(info),
+                            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(MDRawContextX86 *raw_context) {
+    u_int8_t x = 173;
+    for (size_t i = 0; i < sizeof(*raw_context); i++)
+      reinterpret_cast<u_int8_t *>(raw_context)[i] = (x += 17);
+  }
+  
+  SystemInfo system_info;
+  MDRawContextX86 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 GetContextFrame: public StackwalkerX86Fixture, public Test { };
+
+TEST_F(GetContextFrame, Simple) {
+  stack_section.start() = 0x80000000;
+  stack_section.D32(0).D32(0); // end-of-stack marker
+  RegionFromSection();
+  raw_context.eip = 0x40000200;
+  raw_context.ebp = 0x80000000;
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  StackFrameX86 *frame = static_cast<StackFrameX86 *>(frames->at(0));
+  // Check that the values from the original raw context made it
+  // through to the context in the stack frame.
+  EXPECT_TRUE(memcmp(&raw_context, &frame->context, sizeof(raw_context)) == 0);
+}
+
+class GetCallerFrame: public StackwalkerX86Fixture, public Test { };
+
+// Walk a traditional frame. A traditional frame saves the caller's
+// %ebp just below the return address, and has its own %ebp pointing
+// at the saved %ebp.
+TEST_F(GetCallerFrame, Traditional) {
+  stack_section.start() = 0x80000000;
+  Label frame0_ebp, frame1_ebp;
+  stack_section
+    .Append(12, 0)                      // frame 0: space
+    .Mark(&frame0_ebp)                  // frame 0 %ebp points here
+    .D32(frame1_ebp)                    // frame 0: saved %ebp
+    .D32(0x40008679)                    // frame 0: return address
+    .Append(8, 0)                       // frame 1: space
+    .Mark(&frame1_ebp)                  // frame 1 %ebp points here
+    .D32(0)                             // frame 1: saved %ebp (stack end)
+    .D32(0);                            // frame 1: return address (stack end)
+  RegionFromSection();
+  raw_context.eip = 0x4000c7a5;
+  raw_context.esp = stack_section.start().Value();
+  raw_context.ebp = frame0_ebp.Value();
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  EXPECT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x4000c7a5U, frame0->instruction);
+  EXPECT_EQ(0x4000c7a5U, frame0->context.eip);
+  EXPECT_EQ(frame0_ebp.Value(), frame0->context.ebp);
+  EXPECT_EQ(NULL, frame0->windows_frame_info);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_FP, frame1->trust);
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x40008679U, frame1->instruction + 1);
+  EXPECT_EQ(0x40008679U, frame1->context.eip);
+  EXPECT_EQ(frame1_ebp.Value(), frame1->context.ebp);
+  EXPECT_EQ(NULL, frame1->windows_frame_info);
+}
+
+// Walk a traditional frame, but use a bogus %ebp value, forcing a scan
+// of the stack for something that looks like a return address.
+TEST_F(GetCallerFrame, TraditionalScan) {
+  stack_section.start() = 0x80000000;
+  Label frame1_ebp;
+  stack_section
+    // frame 0
+    .D32(0xf065dc76)    // locals area:
+    .D32(0x46ee2167)    // garbage that doesn't look like
+    .D32(0xbab023ec)    // a return address
+    .D32(frame1_ebp)    // saved %ebp (%ebp fails to point here, forcing scan)
+    .D32(0x4000129d)    // return address
+    // frame 1
+    .Append(8, 0)       // space
+    .Mark(&frame1_ebp)  // %ebp points here
+    .D32(0)             // saved %ebp (stack end)
+    .D32(0);            // return address (stack end)
+
+  RegionFromSection();
+  raw_context.eip = 0x4000f49d;
+  raw_context.esp = stack_section.start().Value();
+  // Make the frame pointer bogus, to make the stackwalker scan the stack
+  // for something that looks like a return address.
+  raw_context.ebp = 0xd43eed6e;
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x4000f49dU, frame0->instruction);
+  EXPECT_EQ(0x4000f49dU, frame0->context.eip);
+  EXPECT_EQ(stack_section.start().Value(), frame0->context.esp);
+  EXPECT_EQ(0xd43eed6eU, frame0->context.ebp);
+  EXPECT_EQ(NULL, frame0->windows_frame_info);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_SCAN, frame1->trust);
+  // I'd argue that CONTEXT_VALID_EBP shouldn't be here, since the
+  // walker does not actually fetch the EBP after a scan (forcing the
+  // next frame to be scanned as well). But we'll grandfather the existing
+  // behavior in for now.
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x4000129dU, frame1->instruction + 1);
+  EXPECT_EQ(0x4000129dU, frame1->context.eip);
+  EXPECT_EQ(0x80000014U, frame1->context.esp);
+  EXPECT_EQ(0xd43eed6eU, frame1->context.ebp);
+  EXPECT_EQ(NULL, frame1->windows_frame_info);
+}
+
+// Use Windows frame data (a "STACK WIN 4" record, from a
+// FrameTypeFrameData DIA record) to walk a stack frame.
+TEST_F(GetCallerFrame, WindowsFrameData) {
+  SetModuleSymbols(&module1,
+                   "STACK WIN 4 aa85 176 0 0 4 10 4 0 1"
+                   " $T2 $esp .cbSavedRegs + ="
+                   " $T0 .raSearchStart ="
+                   " $eip $T0 ^ ="
+                   " $esp $T0 4 + ="
+                   " $ebx $T2 4  - ^ ="
+                   " $edi $T2 8  - ^ ="
+                   " $esi $T2 12 - ^ ="
+                   " $ebp $T2 16 - ^ =\n");
+  Label frame1_esp, frame1_ebp;
+  stack_section.start() = 0x80000000;
+  stack_section
+    // frame 0
+    .D32(frame1_ebp)                    // saved regs: %ebp
+    .D32(0xa7120d1a)                    //             %esi
+    .D32(0x630891be)                    //             %edi
+    .D32(0x9068a878)                    //             %ebx
+    .D32(0xa08ea45f)                    // locals: unused
+    .D32(0x40001350)                    // return address
+    // frame 1
+    .Mark(&frame1_esp)
+    .Append(12, 0)                      // empty space
+    .Mark(&frame1_ebp)
+    .D32(0)                             // saved %ebp (stack end)
+    .D32(0);                            // saved %eip (stack end)
+
+  RegionFromSection();
+  raw_context.eip = 0x4000aa85;
+  raw_context.esp = stack_section.start().Value();
+  raw_context.ebp = 0xf052c1de;         // should not be needed to walk frame
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x4000aa85U, frame0->instruction);
+  EXPECT_EQ(0x4000aa85U, frame0->context.eip);
+  EXPECT_EQ(stack_section.start().Value(), frame0->context.esp);
+  EXPECT_EQ(0xf052c1deU, frame0->context.ebp);
+  EXPECT_TRUE(frame0->windows_frame_info != NULL);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CFI, frame1->trust);
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP
+             | StackFrameX86::CONTEXT_VALID_EBX
+             | StackFrameX86::CONTEXT_VALID_ESI
+             | StackFrameX86::CONTEXT_VALID_EDI),
+            frame1->context_validity);
+  EXPECT_EQ(0x40001350U, frame1->instruction + 1);
+  EXPECT_EQ(0x40001350U, frame1->context.eip);
+  EXPECT_EQ(frame1_esp.Value(), frame1->context.esp);
+  EXPECT_EQ(frame1_ebp.Value(), frame1->context.ebp);
+  EXPECT_EQ(0x9068a878U, frame1->context.ebx);
+  EXPECT_EQ(0xa7120d1aU, frame1->context.esi);
+  EXPECT_EQ(0x630891beU, frame1->context.edi);
+  EXPECT_EQ(NULL, frame1->windows_frame_info);
+}
+
+// Use Windows frame data (a "STACK WIN 4" record, from a
+// FrameTypeFrameData DIA record) to walk a frame, and depend on the
+// parameter size from the callee as well.
+TEST_F(GetCallerFrame, WindowsFrameDataParameterSize) {
+  SetModuleSymbols(&module1, "FUNC 1000 100 c module1::wheedle\n");
+  SetModuleSymbols(&module2,
+                   // Note bogus parameter size in FUNC record; we should
+                   // prefer the STACK WIN record, and see '4' below.
+                   "FUNC aa85 176 beef module2::whine\n"
+                   "STACK WIN 4 aa85 176 0 0 4 10 4 0 1"
+                   " $T2 $esp .cbLocals + .cbSavedRegs + ="
+                   " $T0 .raSearchStart ="
+                   " $eip $T0 ^ ="
+                   " $esp $T0 4 + ="
+                   " $ebp $T0 20 - ^ ="
+                   " $ebx $T0 8 - ^ =\n");
+  Label frame0_esp, frame0_ebp;
+  Label frame1_esp;
+  Label frame2_esp, frame2_ebp;
+  stack_section.start() = 0x80000000;
+  stack_section
+    // frame 0, in module1::wheedle.  Traditional frame.
+    .Mark(&frame0_esp)
+    .Append(16, 0)      // frame space
+    .Mark(&frame0_ebp)
+    .D32(0x6fa902e0)    // saved %ebp.  Not a frame pointer.
+    .D32(0x5000aa95)    // return address, in module2::whine
+    // frame 1, in module2::whine.  FrameData frame.
+    .Mark(&frame1_esp)
+    .D32(0xbaa0cb7a)    // argument 3 passed to module1::wheedle
+    .D32(0xbdc92f9f)    // argument 2
+    .D32(0x0b1d8442)    // argument 1
+    .D32(frame2_ebp)    // saved %ebp
+    .D32(0xb1b90a15)    // unused
+    .D32(0xf18e072d)    // unused
+    .D32(0x2558c7f3)    // saved %ebx
+    .D32(0x0365e25e)    // unused
+    .D32(0x2a179e38)    // return address; $T0 points here
+    // frame 2, in no module
+    .Mark(&frame2_esp)
+    .Append(12, 0)      // empty space
+    .Mark(&frame2_ebp)
+    .D32(0)             // saved %ebp (stack end)
+    .D32(0);            // saved %eip (stack end)
+
+  RegionFromSection();
+  raw_context.eip = 0x40001004; // in module1::wheedle
+  raw_context.esp = stack_section.start().Value();
+  raw_context.ebp = frame0_ebp.Value();
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(3U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x40001004U, frame0->instruction);
+  EXPECT_EQ(0x40001004U, frame0->context.eip);
+  EXPECT_EQ(frame0_esp.Value(), frame0->context.esp);
+  EXPECT_EQ(frame0_ebp.Value(), frame0->context.ebp);
+  EXPECT_EQ(&module1, frame0->module);
+  EXPECT_EQ("module1::wheedle", frame0->function_name);
+  EXPECT_EQ(0x40001000U, frame0->function_base);
+  // The FUNC record for module1::wheedle should have produced a
+  // WindowsFrameInfo structure with only the parameter size valid.
+  ASSERT_TRUE(frame0->windows_frame_info != NULL);
+  EXPECT_EQ(WindowsFrameInfo::VALID_PARAMETER_SIZE,
+            frame0->windows_frame_info->valid);
+  EXPECT_EQ(12U, frame0->windows_frame_info->parameter_size);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_FP, frame1->trust);
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x5000aa95U, frame1->instruction + 1);
+  EXPECT_EQ(0x5000aa95U, frame1->context.eip);
+  EXPECT_EQ(frame1_esp.Value(), frame1->context.esp);
+  EXPECT_EQ(0x6fa902e0U, frame1->context.ebp);
+  EXPECT_EQ(&module2, frame1->module);
+  EXPECT_EQ("module2::whine", frame1->function_name);
+  EXPECT_EQ(0x5000aa85U, frame1->function_base);
+  ASSERT_TRUE(frame1->windows_frame_info != NULL);
+  EXPECT_EQ(WindowsFrameInfo::VALID_ALL, frame1->windows_frame_info->valid);
+  // This should not see the 0xbeef parameter size from the FUNC
+  // record, but should instead see the STACK WIN record.
+  EXPECT_EQ(4U, frame1->windows_frame_info->parameter_size);
+
+  StackFrameX86 *frame2 = static_cast<StackFrameX86 *>(frames->at(2));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CFI, frame2->trust);
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP
+             | StackFrameX86::CONTEXT_VALID_EBX),
+            frame2->context_validity);
+  EXPECT_EQ(0x2a179e38U, frame2->instruction + 1);
+  EXPECT_EQ(0x2a179e38U, frame2->context.eip);
+  EXPECT_EQ(frame2_esp.Value(), frame2->context.esp);
+  EXPECT_EQ(frame2_ebp.Value(), frame2->context.ebp);
+  EXPECT_EQ(0x2558c7f3U, frame2->context.ebx);
+  EXPECT_EQ(NULL, frame2->module);
+  EXPECT_EQ(NULL, frame2->windows_frame_info);
+}
+
+// Use Windows frame data (a "STACK WIN 4" record, from a
+// FrameTypeFrameData DIA record) to walk a stack frame, where the
+// expression fails to yield both an $eip and an $ebp value, and we
+// must scan.
+TEST_F(GetCallerFrame, WindowsFrameDataScan) {
+  SetModuleSymbols(&module1,
+                   "STACK WIN 4 c8c 111 0 0 4 10 4 0 1 bad program string\n");
+  // Mark frame 1's PC as the end of the stack.
+  SetModuleSymbols(&module2,
+                   "FUNC 7c38 accf 0 module2::function\n"
+                   "STACK WIN 4 7c38 accf 0 0 4 10 4 0 1 $eip 0 = $ebp 0 =\n");
+  Label frame1_esp;
+  stack_section.start() = 0x80000000;
+  stack_section
+    // frame 0
+    .Append(16, 0x2a)                   // unused, garbage
+    .D32(0x50007ce9)                    // return address
+    // frame 1
+    .Mark(&frame1_esp)
+    .Append(8, 0);                      // empty space
+
+  RegionFromSection();
+  raw_context.eip = 0x40000c9c;
+  raw_context.esp = stack_section.start().Value();
+  raw_context.ebp = 0x2ae314cd;         // should not be needed to walk frame
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x40000c9cU, frame0->instruction);
+  EXPECT_EQ(0x40000c9cU, frame0->context.eip);
+  EXPECT_EQ(stack_section.start().Value(), frame0->context.esp);
+  EXPECT_EQ(0x2ae314cdU, frame0->context.ebp);
+  EXPECT_TRUE(frame0->windows_frame_info != NULL);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_SCAN, frame1->trust);
+  // I'd argue that CONTEXT_VALID_EBP shouldn't be here, since the
+  // walker does not actually fetch the EBP after a scan (forcing the
+  // next frame to be scanned as well). But we'll grandfather the existing
+  // behavior in for now.
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x50007ce9U, frame1->instruction + 1);
+  EXPECT_EQ(0x50007ce9U, frame1->context.eip);
+  EXPECT_EQ(frame1_esp.Value(), frame1->context.esp);
+  EXPECT_TRUE(frame1->windows_frame_info != NULL);
+}
+
+// Use Windows frame data (a "STACK WIN 4" record, from a
+// FrameTypeFrameData DIA record) to walk a stack frame, where the
+// expression yields an $eip that falls outside of any module, and we
+// must scan.
+TEST_F(GetCallerFrame, WindowsFrameDataBadEIPScan) {
+  SetModuleSymbols(&module1,
+                   "STACK WIN 4 6e6 e7 0 0 0 8 4 0 1"
+                   // A traditional frame, actually.
+                   " $eip $ebp 4 + ^ = $esp $ebp 8 + = $ebp $ebp ^ =\n");
+  // Mark frame 1's PC as the end of the stack.
+  SetModuleSymbols(&module2,
+                   "FUNC cfdb 8406 0 module2::function\n"
+                   "STACK WIN 4 cfdb 8406 0 0 0 0 0 0 1 $eip 0 = $ebp 0 =\n");
+  stack_section.start() = 0x80000000;
+
+  // In this stack, the context's %ebp is pointing at the wrong place, so
+  // we need to scan to find the return address, and then scan again to find
+  // the caller's saved %ebp.
+  Label frame0_ebp, frame1_ebp, frame1_esp;
+  stack_section
+    // frame 0
+    .Append(8, 0x2a)            // garbage
+    .Mark(&frame0_ebp)          // frame 0 %ebp points here, but should point
+                                // at *** below
+    // The STACK WIN record says that the following two values are
+    // frame 1's saved %ebp and return address, but the %ebp is wrong;
+    // they're garbage. We will scan for the right values.
+    .D32(0x3d937b2b)            // alleged to be frame 1's saved %ebp
+    .D32(0x17847f5b)            // alleged to be frame 1's return address
+    .D32(frame1_ebp)            // frame 1's real saved %ebp; scan will find
+    .D32(0x2b2b2b2b)            // first word of realigned register save area
+    // *** frame 0 %ebp ought to be pointing here
+    .D32(0x2c2c2c2c)            // realigned locals area
+    .D32(0x5000d000)            // frame 1's real saved %eip; scan will find
+    // Frame 1, in module2::function. The STACK WIN record describes
+    // this as the oldest frame, without referring to its contents, so
+    // we don't need to 
+    .Mark(&frame1_esp)
+    .Mark(&frame1_ebp)          // frame 1 %ebp points here
+    // A dummy value for frame 1's %ebp to point at. The scan recognizes the
+    // saved %ebp because it points to a valid word in the stack memory region.
+    .D32(0x2d2d2d2d);
+
+  RegionFromSection();
+  raw_context.eip = 0x40000700;
+  raw_context.esp = stack_section.start().Value();
+  raw_context.ebp = frame0_ebp.Value();
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x40000700U, frame0->instruction);
+  EXPECT_EQ(0x40000700U, frame0->context.eip);
+  EXPECT_EQ(stack_section.start().Value(), frame0->context.esp);
+  EXPECT_EQ(frame0_ebp.Value(), frame0->context.ebp);
+  EXPECT_TRUE(frame0->windows_frame_info != NULL);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CFI_SCAN, frame1->trust);
+  // I'd argue that CONTEXT_VALID_EBP shouldn't be here, since the
+  // walker does not actually fetch the EBP after a scan (forcing the
+  // next frame to be scanned as well). But we'll grandfather the existing
+  // behavior in for now.
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x5000d000U, frame1->instruction + 1);
+  EXPECT_EQ(0x5000d000U, frame1->context.eip);
+  EXPECT_EQ(frame1_esp.Value(), frame1->context.esp);
+  EXPECT_EQ(frame1_ebp.Value(), frame1->context.ebp);
+  EXPECT_TRUE(frame1->windows_frame_info != NULL);
+}
+
+// Use Windows FrameTypeFPO data to walk a stack frame for a function that
+// does not modify %ebp from the value it had in the caller.
+TEST_F(GetCallerFrame, WindowsFPOUnchangedEBP) {
+  SetModuleSymbols(&module1,
+                   // Note bogus parameter size in FUNC record; we should
+                   // prefer the STACK WIN record, and see '8' below.
+                   "FUNC e8a8 100 feeb module1::discombobulated\n"
+                   "STACK WIN 0 e8a8 100 0 0 8 4 10 0 0 0\n");
+  Label frame0_esp;
+  Label frame1_esp, frame1_ebp;
+  stack_section.start() = 0x80000000;
+  stack_section
+    // frame 0, in module1::wheedle.  FrameTypeFPO (STACK WIN 0) frame.
+    .Mark(&frame0_esp)
+    // no outgoing parameters; this is the youngest frame.
+    .D32(0x7c521352)    // four bytes of saved registers
+    .Append(0x10, 0x42) // local area
+    .D32(0x40009b5b)    // return address, in module1, no function
+    // frame 1, in module1, no function.
+    .Mark(&frame1_esp)
+    .D32(0xf60ea7fc)    // junk
+    .Mark(&frame1_ebp)
+    .D32(0)             // saved %ebp (stack end)
+    .D32(0);            // saved %eip (stack end)
+
+  RegionFromSection();
+  raw_context.eip = 0x4000e8b8; // in module1::whine
+  raw_context.esp = stack_section.start().Value();
+  // Frame pointer unchanged from caller.
+  raw_context.ebp = frame1_ebp.Value();
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x4000e8b8U, frame0->instruction);
+  EXPECT_EQ(0x4000e8b8U, frame0->context.eip);
+  EXPECT_EQ(frame0_esp.Value(), frame0->context.esp);
+  EXPECT_EQ(frame1_ebp.Value(), frame0->context.ebp); // unchanged from caller
+  EXPECT_EQ(&module1, frame0->module);
+  EXPECT_EQ("module1::discombobulated", frame0->function_name);
+  EXPECT_EQ(0x4000e8a8U, frame0->function_base);
+  // The STACK WIN record for module1::discombobulated should have
+  // produced a fully populated WindowsFrameInfo structure.
+  ASSERT_TRUE(frame0->windows_frame_info != NULL);
+  EXPECT_EQ(WindowsFrameInfo::VALID_ALL, frame0->windows_frame_info->valid);
+  EXPECT_EQ(0x10U, frame0->windows_frame_info->local_size);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CFI, frame1->trust);
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x40009b5bU, frame1->instruction + 1);
+  EXPECT_EQ(0x40009b5bU, frame1->context.eip);
+  EXPECT_EQ(frame1_esp.Value(), frame1->context.esp);
+  EXPECT_EQ(frame1_ebp.Value(), frame1->context.ebp);
+  EXPECT_EQ(&module1, frame1->module);
+  EXPECT_EQ("", frame1->function_name);
+  EXPECT_EQ(NULL, frame1->windows_frame_info);
+}
+
+// Use Windows FrameTypeFPO data to walk a stack frame for a function
+// that uses %ebp for its own purposes, saving the value it had in the
+// caller in the standard place in the saved register area.
+TEST_F(GetCallerFrame, WindowsFPOUsedEBP) {
+  SetModuleSymbols(&module1,
+                   // Note bogus parameter size in FUNC record; we should
+                   // prefer the STACK WIN record, and see '8' below.
+                   "FUNC 9aa8 e6 abbe module1::RaisedByTheAliens\n"
+                   "STACK WIN 0 9aa8 e6 a 0 10 8 4 0 0 1\n");
+  Label frame0_esp;
+  Label frame1_esp, frame1_ebp;
+  stack_section.start() = 0x80000000;
+  stack_section
+    // frame 0, in module1::wheedle.  FrameTypeFPO (STACK WIN 0) frame.
+    .Mark(&frame0_esp)
+    // no outgoing parameters; this is the youngest frame.
+    .D32(frame1_ebp)    // saved register area: saved %ebp
+    .D32(0xb68bd5f9)    // saved register area: something else
+    .D32(0xd25d05fc)    // local area
+    .D32(0x4000debe)    // return address, in module1, no function
+    // frame 1, in module1, no function.
+    .Mark(&frame1_esp)
+    .D32(0xf0c9a974)    // junk
+    .Mark(&frame1_ebp)
+    .D32(0)             // saved %ebp (stack end)
+    .D32(0);            // saved %eip (stack end)
+
+  RegionFromSection();
+  raw_context.eip = 0x40009ab8; // in module1::RaisedByTheAliens
+  raw_context.esp = stack_section.start().Value();
+  // RaisedByTheAliens uses %ebp for its own mysterious purposes.
+  raw_context.ebp = 0xecbdd1a5;
+
+  StackwalkerX86 walker(&system_info, &raw_context, &stack_region, &modules,
+                        &supplier, &resolver);
+  ASSERT_TRUE(walker.Walk(&call_stack));
+  frames = call_stack.frames();
+  ASSERT_EQ(2U, frames->size());
+
+  StackFrameX86 *frame0 = static_cast<StackFrameX86 *>(frames->at(0));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameX86::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0x40009ab8U, frame0->instruction);
+  EXPECT_EQ(0x40009ab8U, frame0->context.eip);
+  EXPECT_EQ(frame0_esp.Value(), frame0->context.esp);
+  EXPECT_EQ(0xecbdd1a5, frame0->context.ebp);
+  EXPECT_EQ(&module1, frame0->module);
+  EXPECT_EQ("module1::RaisedByTheAliens", frame0->function_name);
+  EXPECT_EQ(0x40009aa8U, frame0->function_base);
+  // The STACK WIN record for module1::RaisedByTheAliens should have
+  // produced a fully populated WindowsFrameInfo structure.
+  ASSERT_TRUE(frame0->windows_frame_info != NULL);
+  EXPECT_EQ(WindowsFrameInfo::VALID_ALL, frame0->windows_frame_info->valid);
+  EXPECT_EQ("", frame0->windows_frame_info->program_string);
+  EXPECT_TRUE(frame0->windows_frame_info->allocates_base_pointer);
+
+  StackFrameX86 *frame1 = static_cast<StackFrameX86 *>(frames->at(1));
+  EXPECT_EQ(StackFrameX86::FRAME_TRUST_CFI, frame1->trust);
+  ASSERT_EQ((StackFrameX86::CONTEXT_VALID_EIP
+             | StackFrameX86::CONTEXT_VALID_ESP
+             | StackFrameX86::CONTEXT_VALID_EBP),
+            frame1->context_validity);
+  EXPECT_EQ(0x4000debeU, frame1->instruction + 1);
+  EXPECT_EQ(0x4000debeU, frame1->context.eip);
+  EXPECT_EQ(frame1_esp.Value(), frame1->context.esp);
+  EXPECT_EQ(frame1_ebp.Value(), frame1->context.ebp);
+  EXPECT_EQ(&module1, frame1->module);
+  EXPECT_EQ("", frame1->function_name);
+  EXPECT_EQ(NULL, frame1->windows_frame_info);
+}