Basic arm cpu support for processor. r=mark at http://breakpad.appspot.com/49011

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@454 4c0a9323-5329-0410-9bdc-e9ce6186880e

9 files changed, 464 insertions, 9 deletions

diff --git a/src/google_breakpad/common/minidump_cpu_arm.h b/src/google_breakpad/common/minidump_cpu_arm.h
new file mode 100644
index 00000000..bd3d934f
--- /dev/null
+++ b/src/google_breakpad/common/minidump_cpu_arm.h
@@ -0,0 +1,130 @@
+/* Copyright (c) 2009, 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. */
+
+/* minidump_format.h: A cross-platform reimplementation of minidump-related
+ * portions of DbgHelp.h from the Windows Platform SDK.
+ *
+ * (This is C99 source, please don't corrupt it with C++.)
+ *
+ * This file contains the necessary definitions to read minidump files
+ * produced on ARM.  These files may be read on any platform provided
+ * that the alignments of these structures on the processing system are
+ * identical to the alignments of these structures on the producing system.
+ * For this reason, precise-sized types are used.  The structures defined
+ * by this file have been laid out to minimize alignment problems by
+ * ensuring that all members are aligned on their natural boundaries.
+ * In some cases, tail-padding may be significant when different ABIs specify
+ * different tail-padding behaviors.  To avoid problems when reading or
+ * writing affected structures, MD_*_SIZE macros are provided where needed,
+ * containing the useful size of the structures without padding.
+ *
+ * Structures that are defined by Microsoft to contain a zero-length array
+ * are instead defined here to contain an array with one element, as
+ * zero-length arrays are forbidden by standard C and C++.  In these cases,
+ * *_minsize constants are provided to be used in place of sizeof.  For a
+ * cleaner interface to these sizes when using C++, see minidump_size.h.
+ *
+ * These structures are also sufficient to populate minidump files.
+ *
+ * Because precise data type sizes are crucial for this implementation to
+ * function properly and portably, a set of primitive types with known sizes
+ * are used as the basis of each structure defined by this file.
+ *
+ * Author: Julian Seward
+ */
+
+/*
+ * ARM support
+ */
+
+#ifndef GOOGLE_BREAKPAD_COMMON_MINIDUMP_CPU_ARM_H__
+#define GOOGLE_BREAKPAD_COMMON_MINIDUMP_CPU_ARM_H__
+
+#define MD_FLOATINGSAVEAREA_ARM_FPR_COUNT 32
+#define MD_FLOATINGSAVEAREA_ARM_FPEXTRA_COUNT 8
+
+/*
+ * Note that these structures *do not* map directly to the CONTEXT
+ * structure defined in WinNT.h in the Windows Mobile SDK. That structure
+ * does not accomodate VFPv3, and I'm unsure if it was ever used in the
+ * wild anyway, as Windows CE only seems to produce "cedumps" which
+ * are not exactly minidumps.
+ */
+typedef struct {
+  u_int64_t	fpscr;      /* FPU status register */
+
+  /* 32 64-bit floating point registers, d0 .. d31. */
+  u_int64_t	regs[MD_FLOATINGSAVEAREA_ARM_FPR_COUNT];
+
+  /* Miscellaneous control words */
+  u_int32_t     extra[MD_FLOATINGSAVEAREA_ARM_FPEXTRA_COUNT];
+} MDFloatingSaveAreaARM;
+
+#define MD_CONTEXT_ARM_GPR_COUNT 16
+
+typedef struct {
+  /* The next field determines the layout of the structure, and which parts
+   * of it are populated
+   */
+  u_int32_t	context_flags;
+
+  /* 16 32-bit integer registers, r0 .. r15
+   * Note the following fixed uses:
+   *   r13 is the stack pointer
+   *   r14 is the link register
+   *   r15 is the program counter
+   */
+  u_int32_t     iregs[MD_CONTEXT_ARM_GPR_COUNT];
+
+  /* CPSR (flags, basically): 32 bits:
+        bit 31 - N (negative)
+        bit 30 - Z (zero)
+        bit 29 - C (carry)
+        bit 28 - V (overflow)
+        bit 27 - Q (saturation flag, sticky)
+     All other fields -- ignore */
+  u_int32_t    cpsr;
+
+  /* The next field is included with MD_CONTEXT_ARM_FLOATING_POINT */
+  MDFloatingSaveAreaARM float_save;
+
+} MDRawContextARM;
+
+/* For (MDRawContextARM).context_flags.  These values indicate the type of
+ * context stored in the structure. */
+#define MD_CONTEXT_ARM_INTEGER           (MD_CONTEXT_ARM | 0x00000002)
+#define MD_CONTEXT_ARM_FLOATING_POINT    (MD_CONTEXT_ARM | 0x00000004)
+
+#define MD_CONTEXT_ARM_FULL              (MD_CONTEXT_ARM_INTEGER | \
+                                          MD_CONTEXT_ARM_FLOATING_POINT)
+
+#define MD_CONTEXT_ARM_ALL               (MD_CONTEXT_ARM_INTEGER | \
+                                          MD_CONTEXT_ARM_FLOATING_POINT)
+
+#endif  /* GOOGLE_BREAKPAD_COMMON_MINIDUMP_CPU_ARM_H__ */
diff --git a/src/google_breakpad/common/minidump_format.h b/src/google_breakpad/common/minidump_format.h
index 4d9e767f..f3b4a46b 100644
--- a/src/google_breakpad/common/minidump_format.h
+++ b/src/google_breakpad/common/minidump_format.h
@@ -112,12 +112,12 @@ typedef struct {
   u_int32_t context_flags;
 } MDRawContextBase;
 
-#include "minidump_cpu_sparc.h"
-#include "minidump_cpu_x86.h"
+#include "minidump_cpu_amd64.h"
+#include "minidump_cpu_arm.h"
 #include "minidump_cpu_ppc.h"
 #include "minidump_cpu_ppc64.h"
-#include "minidump_cpu_amd64.h"
-
+#include "minidump_cpu_sparc.h"
+#include "minidump_cpu_x86.h"
 
 /*
  * WinVer.h
diff --git a/src/google_breakpad/processor/minidump.h b/src/google_breakpad/processor/minidump.h
index 695a7254..2a83c3f0 100644
--- a/src/google_breakpad/processor/minidump.h
+++ b/src/google_breakpad/processor/minidump.h
@@ -179,10 +179,11 @@ class MinidumpContext : public MinidumpStream {
   // Returns raw CPU-specific context data for the named CPU type.  If the
   // context data does not match the CPU type or does not exist, returns
   // NULL.
-  const MDRawContextX86*   GetContextX86() const;
-  const MDRawContextPPC*   GetContextPPC() const;
   const MDRawContextAMD64* GetContextAMD64() const;
+  const MDRawContextARM*   GetContextARM() const;
+  const MDRawContextPPC*   GetContextPPC() const;
   const MDRawContextSPARC* GetContextSPARC() const;
+  const MDRawContextX86*   GetContextX86() const;
  
   // Print a human-readable representation of the object to stdout.
   void Print();
@@ -216,7 +217,8 @@ class MinidumpContext : public MinidumpStream {
     MDRawContextAMD64* amd64;
     // on Solaris SPARC, sparc is defined as a numeric constant,
     // so variables can NOT be named as sparc
-    MDRawContextSPARC*  ctx_sparc;
+    MDRawContextSPARC* ctx_sparc;
+    MDRawContextARM*   arm;
   } context_;
 };
 
diff --git a/src/google_breakpad/processor/stack_frame_cpu.h b/src/google_breakpad/processor/stack_frame_cpu.h
index 3d3003b7..1e414638 100644
--- a/src/google_breakpad/processor/stack_frame_cpu.h
+++ b/src/google_breakpad/processor/stack_frame_cpu.h
@@ -168,6 +168,33 @@ struct StackFrameSPARC : public StackFrame {
   int context_validity;
 };
 
+struct StackFrameARM : public StackFrame {
+  // ContextValidity should eventually contain entries for the validity of
+  // other nonvolatile (callee-save) registers as in
+  // StackFrameX86::ContextValidity. I suspect this list is sufficient
+  // for arm stackwalking.
+  enum ContextValidity {
+    CONTEXT_VALID_NONE = 0,
+    CONTEXT_VALID_R13 = 1 << 0,
+    CONTEXT_VALID_R14 = 1 << 1,
+    CONTEXT_VALID_R15 = 1 << 2,
+    CONTEXT_VALID_ALL = -1
+  };
+
+  StackFrameARM() : context(), context_validity(CONTEXT_VALID_NONE) {}
+
+  // Register state.  This is only fully valid for the topmost frame in a
+  // stack.  In other frames, the values of nonvolatile registers may be
+  // present, given sufficient debugging information.  Refer to
+  // context_validity.
+  MDRawContextARM context;
+
+  // context_validity is actually ContextValidity, but int is used because
+  // the OR operator doesn't work well with enumerated types.  This indicates
+  // which fields in context are valid.
+  int context_validity;
+};
+
 }  // namespace google_breakpad
 
 #endif  // GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_CPU_H__
diff --git a/src/processor/minidump.cc b/src/processor/minidump.cc
index 49118589..771edd64 100644
--- a/src/processor/minidump.cc
+++ b/src/processor/minidump.cc
@@ -620,6 +620,61 @@ bool MinidumpContext::Read(u_int32_t expected_size) {
         break;
       }
 
+      case MD_CONTEXT_ARM: {
+        if (expected_size != sizeof(MDRawContextARM)) {
+          BPLOG(ERROR) << "MinidumpContext arm size mismatch, " <<
+            expected_size << " != " << sizeof(MDRawContextARM);
+          return false;
+        }
+
+        scoped_ptr<MDRawContextARM> context_arm(new MDRawContextARM());
+
+        // 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_arm->context_flags = context_flags;
+
+        size_t flags_size = sizeof(context_arm->context_flags);
+        u_int8_t* context_after_flags =
+            reinterpret_cast<u_int8_t*>(context_arm.get()) + flags_size;
+        if (!minidump_->ReadBytes(context_after_flags,
+                                  sizeof(MDRawContextARM) - flags_size)) {
+          BPLOG(ERROR) << "MinidumpContext could not read arm 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 arm does not match system info";
+          return false;
+        }
+
+        if (minidump_->swap()) {
+          // context_arm->context_flags was already swapped.
+          for (unsigned int ireg_index = 0;
+               ireg_index < MD_CONTEXT_ARM_GPR_COUNT;
+               ++ireg_index) {
+            Swap(&context_arm->iregs[ireg_index]);
+          }
+          Swap(&context_arm->cpsr);
+          Swap(&context_arm->float_save.fpscr);
+          for (unsigned int fpr_index = 0;
+               fpr_index < MD_FLOATINGSAVEAREA_ARM_FPR_COUNT;
+               ++fpr_index) {
+            Swap(&context_arm->float_save.regs[fpr_index]);
+          }
+          for (unsigned int fpe_index = 0;
+               fpe_index < MD_FLOATINGSAVEAREA_ARM_FPEXTRA_COUNT;
+               ++fpe_index) {
+            Swap(&context_arm->float_save.extra[fpe_index]);
+          }
+        }
+        context_.arm = context_arm.release();
+
+        break;
+      }
+
       default: {
         // Unknown context type - Don't log as an error yet. Let the 
         // caller work that out.
@@ -685,6 +740,15 @@ const MDRawContextSPARC* MinidumpContext::GetContextSPARC() const {
   return context_.ctx_sparc;
 }
 
+const MDRawContextARM* MinidumpContext::GetContextARM() const {
+  if (GetContextCPU() != MD_CONTEXT_ARM) {
+    BPLOG(ERROR) << "MinidumpContext cannot get arm context";
+    return NULL;
+  }
+
+  return context_.arm;
+}
+
 void MinidumpContext::FreeContext() {
   switch (GetContextCPU()) {
     case MD_CONTEXT_X86:
@@ -703,6 +767,10 @@ void MinidumpContext::FreeContext() {
       delete context_.ctx_sparc;
       break;
 
+    case MD_CONTEXT_ARM:
+      delete context_.arm;
+      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
@@ -762,6 +830,11 @@ bool MinidumpContext::CheckAgainstSystemInfo(u_int32_t context_cpu_type) {
       if (system_info_cpu_type == MD_CPU_ARCHITECTURE_SPARC)
         return_value = true;
       break;
+
+    case MD_CONTEXT_ARM:
+      if (system_info_cpu_type == MD_CPU_ARCHITECTURE_ARM)
+        return_value = true;
+      break;
   }
 
   BPLOG_IF(ERROR, !return_value) << "MinidumpContext CPU " <<
@@ -967,6 +1040,36 @@ void MinidumpContext::Print() {
       break;
     }
 
+    case MD_CONTEXT_ARM: {
+      const MDRawContextARM* context_arm = GetContextARM();
+      printf("MDRawContextARM\n");
+      printf("  context_flags       = 0x%x\n",
+             context_arm->context_flags);
+      for (unsigned int ireg_index = 0;
+           ireg_index < MD_CONTEXT_ARM_GPR_COUNT;
+           ++ireg_index) {
+        printf("  iregs[%2d]            = 0x%x\n",
+               ireg_index, context_arm->iregs[ireg_index]);
+      }
+      printf("  cpsr                = 0x%x\n", context_arm->cpsr);
+      printf("  float_save.fpscr     = 0x%" PRIx64 "\n",
+      for (unsigned int fpr_index = 0;
+           fpr_index < MD_FLOATINGSAVEAREA_ARM_FPR_COUNT;
+           ++fpr_index) {
+        printf("  float_save.regs[%2d] = 0x%" PRIx64 "\n",
+               fpr_index, context_arm->float_save.regs[fpr_index]);
+      }
+      for (unsigned int fpe_index = 0;
+           fpe_index < MD_FLOATINGSAVEAREA_ARM_FPEXTRA_COUNT;
+           ++fpe_index) {
+        printf("  float_save.extra[%2d] = 0x%" PRIx64 "\n",
+               fpe_index, context_arm->float_save.extra[fpe_index]);
+      }
+
+             context_arm->float_save.fpscr);
+      break;
+    }
+
     default: {
       break;
     }
@@ -2727,8 +2830,8 @@ MinidumpContext* MinidumpException::GetContext() {
 
     scoped_ptr<MinidumpContext> context(new MinidumpContext(minidump_));
 
-    // Don't log as an error if we can still fall back on th thread's context
-    // (which must be possible if we got his far.)
+    // Don't log as an error if we can still fall back on the thread's context
+    // (which must be possible if we got this far.)
     if (!context->Read(exception_.thread_context.data_size)) {
       BPLOG(INFO) << "MinidumpException cannot read context";
       return NULL;
@@ -3006,6 +3109,10 @@ string MinidumpSystemInfo::GetCPU() {
       cpu = "x86";
       break;
 
+    case MD_CPU_ARCHITECTURE_AMD64:
+      cpu = "x86-64";
+      break;
+
     case MD_CPU_ARCHITECTURE_PPC:
       cpu = "ppc";
       break;
@@ -3014,6 +3121,10 @@ string MinidumpSystemInfo::GetCPU() {
       cpu = "sparc";
       break;
 
+    case MD_CPU_ARCHITECTURE_ARM:
+      cpu = "arm";
+      break;
+
     default:
       BPLOG(ERROR) << "MinidumpSystemInfo unknown CPU for architecture " <<
                       HexString(system_info_.processor_architecture);
diff --git a/src/processor/minidump_processor.cc b/src/processor/minidump_processor.cc
index 24b03e9d..e2b5bd3d 100644
--- a/src/processor/minidump_processor.cc
+++ b/src/processor/minidump_processor.cc
@@ -308,6 +308,11 @@ bool MinidumpProcessor::GetCPUInfo(Minidump *dump, SystemInfo *info) {
       break;
     }
 
+    case MD_CPU_ARCHITECTURE_ARM: {
+      info->cpu = "arm";
+      break;
+    }
+
     default: {
       // Assign the numeric architecture ID into the CPU string.
       char cpu_string[7];
diff --git a/src/processor/stackwalker.cc b/src/processor/stackwalker.cc
index 96ee6db0..c8f0da54 100644
--- a/src/processor/stackwalker.cc
+++ b/src/processor/stackwalker.cc
@@ -52,6 +52,7 @@
 #include "processor/stackwalker_sparc.h"
 #include "processor/stackwalker_x86.h"
 #include "processor/stackwalker_amd64.h"
+#include "processor/stackwalker_arm.h"
 
 namespace google_breakpad {
 
@@ -181,6 +182,13 @@ Stackwalker* Stackwalker::StackwalkerForCPU(
                                              memory, modules, supplier,
                                              resolver);
       break;
+
+    case MD_CONTEXT_ARM:
+      cpu_stackwalker = new StackwalkerARM(system_info,
+                                           context->GetContextARM(),
+                                           memory, modules, supplier,
+                                           resolver);
+      break;
   }
 
   BPLOG_IF(ERROR, !cpu_stackwalker) << "Unknown CPU type " << HexString(cpu) <<
diff --git a/src/processor/stackwalker_arm.cc b/src/processor/stackwalker_arm.cc
new file mode 100644
index 00000000..cf241c86
--- /dev/null
+++ b/src/processor/stackwalker_arm.cc
@@ -0,0 +1,92 @@
+// Copyright (c) 2009, 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_arm.cc: arm-specific stackwalker.
+//
+// See stackwalker_arm.h for documentation.
+//
+// Author: Mark Mentovai, Ted Mielczarek
+
+
+#include "processor/stackwalker_arm.h"
+#include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "processor/logging.h"
+
+namespace google_breakpad {
+
+
+StackwalkerARM::StackwalkerARM(const SystemInfo *system_info,
+                               const MDRawContextARM *context,
+                               MemoryRegion *memory,
+                               const CodeModules *modules,
+                               SymbolSupplier *supplier,
+                               SourceLineResolverInterface *resolver)
+    : Stackwalker(system_info, memory, modules, supplier, resolver),
+      context_(context) {
+}
+
+
+StackFrame* StackwalkerARM::GetContextFrame() {
+  if (!context_ || !memory_) {
+    BPLOG(ERROR) << "Can't get context frame without context or memory";
+    return NULL;
+  }
+
+  StackFrameARM *frame = new StackFrameARM();
+
+  // The instruction pointer is stored directly in a register (r15), so pull it
+  // straight out of the CPU context structure.
+  frame->context = *context_;
+  frame->context_validity = StackFrameARM::CONTEXT_VALID_ALL;
+  frame->instruction = frame->context.iregs[15];
+
+  return frame;
+}
+
+
+StackFrame* StackwalkerARM::GetCallerFrame(
+    const CallStack *stack,
+    const vector< linked_ptr<StackFrameInfo> > &stack_frame_info) {
+  if (!memory_ || !stack) {
+    BPLOG(ERROR) << "Can't get caller frame without memory or stack";
+    return NULL;
+  }
+
+  StackFrameARM *last_frame = static_cast<StackFrameARM*>(
+      stack->frames()->back());
+
+  // TODO: Can't actually walk the stack on ARM without the CFI data.
+  // Implement this when the CFI symbol dumper changes have landed.
+  return NULL;
+}
+
+
+}  // namespace google_breakpad
diff --git a/src/processor/stackwalker_arm.h b/src/processor/stackwalker_arm.h
new file mode 100644
index 00000000..4a4756b4
--- /dev/null
+++ b/src/processor/stackwalker_arm.h
@@ -0,0 +1,80 @@
+// Copyright (c) 2009, 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_arm.h: arm-specific stackwalker.
+//
+// Provides stack frames given arm register context and a memory region
+// corresponding to an arm stack.
+//
+// Author: Mark Mentovai, Ted Mielczarek
+
+
+#ifndef PROCESSOR_STACKWALKER_ARM_H__
+#define PROCESSOR_STACKWALKER_ARM_H__
+
+
+#include "google_breakpad/common/breakpad_types.h"
+#include "google_breakpad/common/minidump_format.h"
+#include "google_breakpad/processor/stackwalker.h"
+
+namespace google_breakpad {
+
+class CodeModules;
+
+class StackwalkerARM : public Stackwalker {
+ public:
+  // context is an arm context object that gives access to arm-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.
+  StackwalkerARM(const SystemInfo *system_info,
+                 const MDRawContextARM *context,
+                 MemoryRegion *memory,
+                 const CodeModules *modules,
+                 SymbolSupplier *supplier,
+                 SourceLineResolverInterface *resolver);
+
+ private:
+  // Implementation of Stackwalker, using arm context and stack conventions.
+  // TODO: currently stubbed out, needs CFI symbol dumper support
+  virtual StackFrame* GetContextFrame();
+  virtual StackFrame* GetCallerFrame(
+      const CallStack *stack,
+      const vector< linked_ptr<StackFrameInfo> > &stack_frame_info);
+
+  // Stores the CPU context corresponding to the innermost stack frame to
+  // be returned by GetContextFrame.
+  const MDRawContextARM *context_;
+};
+
+
+}  // namespace google_breakpad
+
+
+#endif  // PROCESSOR_STACKWALKER_ARM_H__