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diff --git a/externals/breakpad/src/processor/stackwalker_arm_unittest.cc b/externals/breakpad/src/processor/stackwalker_arm_unittest.cc
new file mode 100644
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+++ b/externals/breakpad/src/processor/stackwalker_arm_unittest.cc
@@ -0,0 +1,982 @@
+// Copyright 2010 Google LLC
+//
+// 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 LLC 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_arm_unittest.cc: Unit tests for StackwalkerARM class.
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>  // Must come first
+#endif
+
+#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_arm.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::StackFrameARM;
+using google_breakpad::Stackwalker;
+using google_breakpad::StackwalkerARM;
+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::DoAll;
+using testing::Return;
+using testing::SetArgumentPointee;
+using testing::Test;
+
+class StackwalkerARMFixture {
+ public:
+  StackwalkerARMFixture()
+    : 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 = "Lugubrious Labrador";
+    system_info.cpu = "arm";
+    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(MDRawContextARM *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;
+  MDRawContextARM 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 StackwalkerARMFixture, public Test { };
+
+TEST_F(SanityCheck, NoResolver) {
+  // Since we have no call frame information, and all unwinding
+  // requires call frame information, the stack walk will end after
+  // the first frame.
+  StackFrameSymbolizer frame_symbolizer(NULL, NULL);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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(0U, modules_without_symbols.size());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(1U, frames->size());
+  StackFrameARM *frame = static_cast<StackFrameARM*>(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 StackwalkerARMFixture, public Test { };
+
+TEST_F(GetContextFrame, Simple) {
+  // Since we have no call frame information, and all unwinding
+  // requires call frame information, the stack walk will end after
+  // the first frame.
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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());
+  StackFrameARM *frame = static_cast<StackFrameARM*>(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) {
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, 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(0U, modules_without_symbols.size());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(1U, frames->size());
+  StackFrameARM *frame = static_cast<StackFrameARM*>(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 StackwalkerARMFixture, 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 = 0x50000100;
+  uint32_t return_address2 = 0x50000900;
+  Label frame1_sp, frame2_sp;
+  stack_section
+    // frame 0
+    .Append(16, 0)                      // space
+
+    .D32(0x40090000)                    // junk that's not
+    .D32(0x60000000)                    // a return address
+
+    .D32(return_address1)               // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(16, 0)                      // space
+
+    .D32(0xF0000000)                    // more junk
+    .D32(0x0000000D)
+
+    .D32(return_address2)               // actual return address
+    // frame 2
+    .Mark(&frame2_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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(3U, frames->size());
+
+  StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+
+  StackFrameARM *frame1 = static_cast<StackFrameARM*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame1->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame1->context_validity);
+  EXPECT_EQ(return_address1, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+
+  StackFrameARM *frame2 = static_cast<StackFrameARM*>(frames->at(2));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame2->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame2->context_validity);
+  EXPECT_EQ(return_address2, frame2->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(frame2_sp.Value(), frame2->context.iregs[MD_CONTEXT_ARM_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 = 0x50000200;
+  Label frame1_sp;
+
+  stack_section
+    // frame 0
+    .Append(16, 0)                      // space
+
+    .D32(0x40090000)                    // junk that's not
+    .D32(0x60000000)                    // a return address
+
+    .D32(0x40001000)                    // a couple of plausible addresses
+    .D32(0x5000F000)                    // that are not within functions
+
+    .D32(return_address)                // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40000200;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
+
+  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);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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());
+
+  StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameARM::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(0x40000100U, frame0->function_base);
+
+  StackFrameARM *frame1 = static_cast<StackFrameARM*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame1->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame1->context_validity);
+  EXPECT_EQ(return_address, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+  EXPECT_EQ("marsupial", frame1->function_name);
+  EXPECT_EQ(0x50000100U, frame1->function_base);
+}
+
+TEST_F(GetCallerFrame, ScanFirstFrame) {
+  // If the stackwalker resorts to stack scanning, it will scan much
+  // farther to find the caller of the context frame.
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x50000100;
+  uint32_t return_address2 = 0x50000900;
+  Label frame1_sp, frame2_sp;
+  stack_section
+    // frame 0
+    .Append(32, 0)                      // space
+
+    .D32(0x40090000)                    // junk that's not
+    .D32(0x60000000)                    // a return address
+
+    .Append(96, 0)                      // more space
+
+    .D32(return_address1)               // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(32, 0)                      // space
+
+    .D32(0xF0000000)                    // more junk
+    .D32(0x0000000D)
+
+    .Append(136, 0)                     // more space
+
+    .D32(return_address2)               // actual return address
+                                        // (won't be found)
+    // frame 2
+    .Mark(&frame2_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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());
+
+  StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+
+  StackFrameARM *frame1 = static_cast<StackFrameARM*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame1->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame1->context_validity);
+  EXPECT_EQ(return_address1, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_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 addresses located within loaded modules are
+  // considered valid return addresses.
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x50000100;
+  uint32_t return_address2 = 0x50000900;
+  Label frame1_sp, frame2_sp;
+  stack_section
+    // frame 0
+    .Append(16, 0)                      // space
+
+    .D32(0x40090000)                    // junk that's not
+    .D32(0x60000000)                    // a return address
+
+    .D32(return_address1)               // actual return address
+    // frame 1
+    .Mark(&frame1_sp)
+    .Append(16, 0)                      // space
+
+    .D32(0xF0000000)                    // more junk
+    .D32(0x0000000D)
+
+    .D32(return_address2)               // actual return address
+    // frame 2
+    .Mark(&frame2_sp)
+    .Append(32, 0);                     // end of stack
+  RegionFromSection();
+
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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());
+
+  StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+}
+
+struct CFIFixture: public StackwalkerARMFixture {
+  CFIFixture() {
+    // Provide a bunch of STACK CFI records; we'll walk to the caller
+    // from every point in this series, expecting to find the same set
+    // of register values.
+    SetModuleSymbols(&module1,
+                     // The youngest frame's function.
+                     "FUNC 4000 1000 10 enchiridion\n"
+                     // Initially, nothing has been pushed on the stack,
+                     // and the return address is still in the link register.
+                     "STACK CFI INIT 4000 100 .cfa: sp .ra: lr\n"
+                     // Push r4, the frame pointer, and the link register.
+                     "STACK CFI 4001 .cfa: sp 12 + r4: .cfa 12 - ^"
+                     " r11: .cfa 8 - ^ .ra: .cfa 4 - ^\n"
+                     // Save r4..r7 in r0..r3: verify that we populate
+                     // the youngest frame with all the values we have.
+                     "STACK CFI 4002 r4: r0 r5: r1 r6: r2 r7: r3\n"
+                     // Restore r4..r7. Save the non-callee-saves register r1.
+                     "STACK CFI 4003 .cfa: sp 16 + r1: .cfa 16 - ^"
+                     " r4: r4 r5: r5 r6: r6 r7: r7\n"
+                     // Move the .cfa back four bytes, to point at the return
+                     // address, and restore the sp explicitly.
+                     "STACK CFI 4005 .cfa: sp 12 + r1: .cfa 12 - ^"
+                     " r11: .cfa 4 - ^ .ra: .cfa ^ sp: .cfa 4 +\n"
+                     // Recover the PC explicitly from a new stack slot;
+                     // provide garbage for the .ra.
+                     "STACK CFI 4006 .cfa: sp 16 + pc: .cfa 16 - ^\n"
+
+                     // The calling function.
+                     "FUNC 5000 1000 10 epictetus\n"
+                     // Mark it as end of stack.
+                     "STACK CFI INIT 5000 1000 .cfa: 0 .ra: 0\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: lr\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.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
+    expected.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
+    expected.iregs[4] = 0xb5d55e68;
+    expected.iregs[5] = 0xebd134f3;
+    expected.iregs[6] = 0xa31e74bc;
+    expected.iregs[7] = 0x2dcb16b3;
+    expected.iregs[8] = 0x2ada2137;
+    expected.iregs[9] = 0xbbbb557d;
+    expected.iregs[10] = 0x48bf8ca7;
+    expected.iregs[MD_CONTEXT_ARM_REG_FP] = 0x8112e110;
+
+    // Expect CFI to recover all callee-saves 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 = (StackFrameARM::CONTEXT_VALID_PC |
+                         StackFrameARM::CONTEXT_VALID_SP |
+                         StackFrameARM::CONTEXT_VALID_R4 |
+                         StackFrameARM::CONTEXT_VALID_R5 |
+                         StackFrameARM::CONTEXT_VALID_R6 |
+                         StackFrameARM::CONTEXT_VALID_R7 |
+                         StackFrameARM::CONTEXT_VALID_R8 |
+                         StackFrameARM::CONTEXT_VALID_R9 |
+                         StackFrameARM::CONTEXT_VALID_R10 |
+                         StackFrameARM::CONTEXT_VALID_FP);
+
+    // By default, context frames provide all registers, as normal.
+    context_frame_validity = StackFrameARM::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_ARM_REG_SP] = stack_section.start().Value();
+
+    StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+    StackwalkerARM walker(&system_info, &raw_context, -1, &stack_region,
+                          &modules, &frame_symbolizer);
+    walker.SetContextFrameValidity(context_frame_validity);
+    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());
+
+    StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+    EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+    ASSERT_EQ(context_frame_validity, frame0->context_validity);
+    EXPECT_EQ("enchiridion", frame0->function_name);
+    EXPECT_EQ(0x40004000U, frame0->function_base);
+
+    StackFrameARM *frame1 = static_cast<StackFrameARM*>(frames->at(1));
+    EXPECT_EQ(StackFrame::FRAME_TRUST_CFI, frame1->trust);
+    ASSERT_EQ(expected_validity, frame1->context_validity);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R1)
+      EXPECT_EQ(expected.iregs[1], frame1->context.iregs[1]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R4)
+      EXPECT_EQ(expected.iregs[4], frame1->context.iregs[4]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R5)
+      EXPECT_EQ(expected.iregs[5], frame1->context.iregs[5]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R6)
+      EXPECT_EQ(expected.iregs[6], frame1->context.iregs[6]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R7)
+      EXPECT_EQ(expected.iregs[7], frame1->context.iregs[7]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R8)
+      EXPECT_EQ(expected.iregs[8], frame1->context.iregs[8]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R9)
+      EXPECT_EQ(expected.iregs[9], frame1->context.iregs[9]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_R10)
+      EXPECT_EQ(expected.iregs[10], frame1->context.iregs[10]);
+    if (expected_validity & StackFrameARM::CONTEXT_VALID_FP)
+      EXPECT_EQ(expected.iregs[MD_CONTEXT_ARM_REG_FP],
+                frame1->context.iregs[MD_CONTEXT_ARM_REG_FP]);
+
+    // We would never have gotten a frame in the first place if the SP
+    // and PC weren't valid or ->instruction weren't set.
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_ARM_REG_SP],
+              frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_ARM_REG_PC],
+              frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+    EXPECT_EQ(expected.iregs[MD_CONTEXT_ARM_REG_PC],
+              frame1->instruction + 2);
+    EXPECT_EQ("epictetus", frame1->function_name);
+  }
+
+  // The values we expect to find for the caller's registers.
+  MDRawContextARM 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 { };
+
+TEST_F(CFI, At4000) {
+  stack_section.start() = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004000;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = 0x40005510;
+  CheckWalk();
+}
+
+TEST_F(CFI, At4001) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0xb5d55e68)            // saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0x40005510)            // return address
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004001;
+  raw_context.iregs[4] = 0x635adc9f;                     // distinct callee r4
+  raw_context.iregs[MD_CONTEXT_ARM_REG_FP] = 0xbe145fc4; // distinct callee fp
+  CheckWalk();
+}
+
+// As above, but unwind from a context that has only the PC and SP.
+TEST_F(CFI, At4001LimitedValidity) {
+  context_frame_validity =
+    StackFrameARM::CONTEXT_VALID_PC | StackFrameARM::CONTEXT_VALID_SP;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004001;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_FP] = 0xbe145fc4; // distinct callee fp
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0xb5d55e68)            // saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0x40005510)            // return address
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  expected_validity = (StackFrameARM::CONTEXT_VALID_PC
+                       | StackFrameARM::CONTEXT_VALID_SP
+                       | StackFrameARM::CONTEXT_VALID_FP
+                       | StackFrameARM::CONTEXT_VALID_R4);
+  CheckWalk();
+}
+
+TEST_F(CFI, At4002) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0xfb81ff3d)            // no longer saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0x40005510)            // return address
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004002;
+  raw_context.iregs[0] = 0xb5d55e68;  // saved r4
+  raw_context.iregs[1] = 0xebd134f3;  // saved r5
+  raw_context.iregs[2] = 0xa31e74bc;  // saved r6
+  raw_context.iregs[3] = 0x2dcb16b3;  // saved r7
+  raw_context.iregs[4] = 0xfdd35466;  // distinct callee r4
+  raw_context.iregs[5] = 0xf18c946c;  // distinct callee r5
+  raw_context.iregs[6] = 0xac2079e8;  // distinct callee r6
+  raw_context.iregs[7] = 0xa449829f;  // distinct callee r7
+  raw_context.iregs[MD_CONTEXT_ARM_REG_FP] = 0xbe145fc4; // distinct callee fp
+  CheckWalk();
+}
+
+TEST_F(CFI, At4003) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0x48c8dd5a)            // saved r1 (even though it's not callee-saves)
+    .D32(0xcb78040e)            // no longer saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0x40005510)            // return address
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004003;
+  raw_context.iregs[1] = 0xfb756319;                     // distinct callee r1
+  raw_context.iregs[MD_CONTEXT_ARM_REG_FP] = 0x0a2857ea; // distinct callee fp
+  expected.iregs[1] = 0x48c8dd5a;    // caller's r1
+  expected_validity |= StackFrameARM::CONTEXT_VALID_R1;
+  CheckWalk();
+}
+
+// We have no new rule at module offset 0x4004, so the results here should
+// be the same as those at module offset 0x4003.
+TEST_F(CFI, At4004) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0x48c8dd5a)            // saved r1 (even though it's not callee-saves)
+    .D32(0xcb78040e)            // no longer saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0x40005510)            // return address
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004004;
+  raw_context.iregs[1] = 0xfb756319; // distinct callee r1
+  expected.iregs[1] = 0x48c8dd5a; // caller's r1
+  expected_validity |= StackFrameARM::CONTEXT_VALID_R1;
+  CheckWalk();
+}
+
+// Here we move the .cfa, but provide an explicit rule to recover the SP,
+// so again there should be no change in the registers recovered.
+TEST_F(CFI, At4005) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0x48c8dd5a)            // saved r1 (even though it's not callee-saves)
+    .D32(0xf013f841)            // no longer saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0x40005510)            // return address
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004005;
+  raw_context.iregs[1] = 0xfb756319; // distinct callee r1
+  expected.iregs[1] = 0x48c8dd5a; // caller's r1
+  expected_validity |= StackFrameARM::CONTEXT_VALID_R1;
+  CheckWalk();
+}
+
+// Here we provide an explicit rule for the PC, and have the saved .ra be
+// bogus.
+TEST_F(CFI, At4006) {
+  Label frame1_sp = expected.iregs[MD_CONTEXT_ARM_REG_SP];
+  stack_section
+    .D32(0x40005510)            // saved pc
+    .D32(0x48c8dd5a)            // saved r1 (even though it's not callee-saves)
+    .D32(0xf013f841)            // no longer saved r4
+    .D32(0x8112e110)            // saved fp
+    .D32(0xf8d15783)            // .ra rule recovers this, which is garbage
+    .Mark(&frame1_sp);          // This effectively sets stack_section.start().
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40004006;
+  raw_context.iregs[1] = 0xfb756319; // callee's r1, different from caller's
+  expected.iregs[1] = 0x48c8dd5a; // caller's r1
+  expected_validity |= StackFrameARM::CONTEXT_VALID_R1;
+  CheckWalk();
+}
+
+// Check that we reject rules that would cause the stack pointer to
+// move in the wrong direction.
+TEST_F(CFI, RejectBackwards) {
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40006000;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = 0x40005510;
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40007000;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = 0x80000000;
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, -1, &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());
+}
+
+class StackwalkerARMFixtureIOS : public StackwalkerARMFixture {
+ public:
+  StackwalkerARMFixtureIOS() {
+    // iOS_test is used instead of iOS because the stackwalker has a check to
+    // avoid using CFI for iOS dumps. This is a workaround for bad CFI being
+    // produced by dump_syms for iOS.
+    // https://bugs.chromium.org/p/google-breakpad/issues/detail?id=764
+    system_info.os = "iOS_test";
+    system_info.os_short = "ios_test";
+  }
+};
+
+class GetFramesByFramePointer: public StackwalkerARMFixtureIOS, public Test { };
+
+TEST_F(GetFramesByFramePointer, OnlyFramePointer) {
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x50000100;
+  uint32_t return_address2 = 0x50000900;
+  Label frame1_sp, frame2_sp;
+  Label frame1_fp, frame2_fp;
+  stack_section
+    // frame 0
+    .Append(32, 0)           // Whatever values on the stack.
+    .D32(0x0000000D)         // junk that's not
+    .D32(0xF0000000)         // a return address.
+
+    .Mark(&frame1_fp)        // Next fp will point to the next value.
+    .D32(frame2_fp)          // Save current frame pointer.
+    .D32(return_address2)    // Save current link register.
+    .Mark(&frame1_sp)
+
+    // frame 1
+    .Append(32, 0)           // Whatever values on the stack.
+    .D32(0x0000000D)         // junk that's not
+    .D32(0xF0000000)         // a return address.
+
+    .Mark(&frame2_fp)
+    .D32(0)
+    .D32(0)
+    .Mark(&frame2_sp)
+
+    // frame 2
+    .Append(32, 0)           // Whatever values on the stack.
+    .D32(0x0000000D)         // junk that's not
+    .D32(0xF0000000);        // a return address.
+  RegionFromSection();
+
+
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x40005510;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = return_address1;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_IOS_FP] = frame1_fp.Value();
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, MD_CONTEXT_ARM_REG_IOS_FP,
+                        &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(3U, frames->size());
+
+  StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+
+  StackFrameARM *frame1 = static_cast<StackFrameARM*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_FP, frame1->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_LR |
+             StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame1->context_validity);
+  EXPECT_EQ(return_address1, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(return_address2, frame1->context.iregs[MD_CONTEXT_ARM_REG_LR]);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+  EXPECT_EQ(frame2_fp.Value(),
+            frame1->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
+
+  StackFrameARM *frame2 = static_cast<StackFrameARM*>(frames->at(2));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_FP, frame2->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_LR |
+             StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame2->context_validity);
+  EXPECT_EQ(return_address2, frame2->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(0U, frame2->context.iregs[MD_CONTEXT_ARM_REG_LR]);
+  EXPECT_EQ(frame2_sp.Value(), frame2->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+  EXPECT_EQ(0U, frame2->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
+}
+
+TEST_F(GetFramesByFramePointer, FramePointerAndCFI) {
+  // Provide the standatd STACK CFI records that is obtained when exmining an
+  // executable produced by XCode.
+  SetModuleSymbols(&module1,
+                     // Adding a function in CFI.
+                     "FUNC 4000 1000 10 enchiridion\n"
+
+                     "STACK CFI INIT 4000 100 .cfa: sp 0 + .ra: lr\n"
+                     "STACK CFI 4001 .cfa: sp 8 + .ra: .cfa -4 + ^"
+                     " r7: .cfa -8 + ^\n"
+                     "STACK CFI 4002 .cfa: r7 8 +\n"
+                  );
+
+  stack_section.start() = 0x80000000;
+  uint32_t return_address1 = 0x40004010;
+  uint32_t return_address2 = 0x50000900;
+  Label frame1_sp, frame2_sp;
+  Label frame1_fp, frame2_fp;
+  stack_section
+    // frame 0
+    .Append(32, 0)           // Whatever values on the stack.
+    .D32(0x0000000D)         // junk that's not
+    .D32(0xF0000000)         // a return address.
+
+    .Mark(&frame1_fp)        // Next fp will point to the next value.
+    .D32(frame2_fp)          // Save current frame pointer.
+    .D32(return_address2)    // Save current link register.
+    .Mark(&frame1_sp)
+
+    // frame 1
+    .Append(32, 0)           // Whatever values on the stack.
+    .D32(0x0000000D)         // junk that's not
+    .D32(0xF0000000)         // a return address.
+
+    .Mark(&frame2_fp)
+    .D32(0)
+    .D32(0)
+    .Mark(&frame2_sp)
+
+    // frame 2
+    .Append(32, 0)           // Whatever values on the stack.
+    .D32(0x0000000D)         // junk that's not
+    .D32(0xF0000000);        // a return address.
+  RegionFromSection();
+
+
+  raw_context.iregs[MD_CONTEXT_ARM_REG_PC] = 0x50000400;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_LR] = return_address1;
+  raw_context.iregs[MD_CONTEXT_ARM_REG_IOS_FP] = frame1_fp.Value();
+  raw_context.iregs[MD_CONTEXT_ARM_REG_SP] = stack_section.start().Value();
+
+  StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+  StackwalkerARM walker(&system_info, &raw_context, MD_CONTEXT_ARM_REG_IOS_FP,
+                        &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("module2", modules_without_symbols[0]->debug_file());
+  ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+  frames = call_stack.frames();
+  ASSERT_EQ(3U, frames->size());
+
+  StackFrameARM *frame0 = static_cast<StackFrameARM*>(frames->at(0));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame0->trust);
+  ASSERT_EQ(StackFrameARM::CONTEXT_VALID_ALL, frame0->context_validity);
+  EXPECT_EQ(0, memcmp(&raw_context, &frame0->context, sizeof(raw_context)));
+
+  StackFrameARM *frame1 = static_cast<StackFrameARM*>(frames->at(1));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_FP, frame1->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_LR |
+             StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame1->context_validity);
+  EXPECT_EQ(return_address1, frame1->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(return_address2, frame1->context.iregs[MD_CONTEXT_ARM_REG_LR]);
+  EXPECT_EQ(frame1_sp.Value(), frame1->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+  EXPECT_EQ(frame2_fp.Value(),
+            frame1->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
+  EXPECT_EQ("enchiridion", frame1->function_name);
+  EXPECT_EQ(0x40004000U, frame1->function_base);
+
+
+  StackFrameARM *frame2 = static_cast<StackFrameARM*>(frames->at(2));
+  EXPECT_EQ(StackFrame::FRAME_TRUST_CFI, frame2->trust);
+  ASSERT_EQ((StackFrameARM::CONTEXT_VALID_PC |
+             StackFrameARM::CONTEXT_VALID_LR |
+             StackFrameARM::RegisterValidFlag(MD_CONTEXT_ARM_REG_IOS_FP) |
+             StackFrameARM::CONTEXT_VALID_SP),
+            frame2->context_validity);
+  EXPECT_EQ(return_address2, frame2->context.iregs[MD_CONTEXT_ARM_REG_PC]);
+  EXPECT_EQ(0U, frame2->context.iregs[MD_CONTEXT_ARM_REG_LR]);
+  EXPECT_EQ(frame2_sp.Value(), frame2->context.iregs[MD_CONTEXT_ARM_REG_SP]);
+  EXPECT_EQ(0U, frame2->context.iregs[MD_CONTEXT_ARM_REG_IOS_FP]);
+}