Re-enable libunwind for arm.
Update to handle the new optimized way that libunwind works.
In addition, a small refactor of the BacktraceMap code.
A few new tests of for good measure.
Change-Id: I2f9b4f5ad5a0dfe907b31febee76e4b9b94fb76f
diff --git a/libbacktrace/BacktraceImpl.cpp b/libbacktrace/BacktraceImpl.cpp
new file mode 100644
index 0000000..39296b4
--- /dev/null
+++ b/libbacktrace/BacktraceImpl.cpp
@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+
+#include <string>
+
+#include <backtrace/Backtrace.h>
+#include <backtrace/BacktraceMap.h>
+
+#include "BacktraceImpl.h"
+#include "thread_utils.h"
+
+//-------------------------------------------------------------------------
+// Backtrace functions.
+//-------------------------------------------------------------------------
+Backtrace::Backtrace(BacktraceImpl* impl, pid_t pid, BacktraceMap* map)
+ : pid_(pid), tid_(-1), map_(map), map_shared_(true), impl_(impl) {
+ impl_->SetParent(this);
+
+ if (map_ == NULL) {
+ map_ = BacktraceMap::Create(pid);
+ map_shared_ = false;
+ }
+}
+
+Backtrace::~Backtrace() {
+ if (impl_) {
+ delete impl_;
+ impl_ = NULL;
+ }
+
+ if (map_ && !map_shared_) {
+ delete map_;
+ map_ = NULL;
+ }
+}
+
+bool Backtrace::Unwind(size_t num_ignore_frames) {
+ return impl_->Unwind(num_ignore_frames);
+}
+
+extern "C" char* __cxa_demangle(const char* mangled, char* buf, size_t* len,
+ int* status);
+
+std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
+ std::string func_name = impl_->GetFunctionNameRaw(pc, offset);
+ if (!func_name.empty()) {
+#if defined(__APPLE__)
+ // Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7.
+ if (func_name[0] != '_') {
+ return func_name;
+ }
+#endif
+ char* name = __cxa_demangle(func_name.c_str(), 0, 0, 0);
+ if (name) {
+ func_name = name;
+ free(name);
+ }
+ }
+ return func_name;
+}
+
+bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, uint32_t* out_value) {
+ if (ptr & 3) {
+ BACK_LOGW("invalid pointer %p", (void*)ptr);
+ *out_value = (uint32_t)-1;
+ return false;
+ }
+ return true;
+}
+
+std::string Backtrace::FormatFrameData(size_t frame_num) {
+ if (frame_num >= frames_.size()) {
+ return "";
+ }
+ return FormatFrameData(&frames_[frame_num]);
+}
+
+std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) {
+ const char* map_name;
+ if (frame->map && !frame->map->name.empty()) {
+ map_name = frame->map->name.c_str();
+ } else {
+ map_name = "<unknown>";
+ }
+
+ uintptr_t relative_pc;
+ if (frame->map) {
+ relative_pc = frame->pc - frame->map->start;
+ } else {
+ relative_pc = frame->pc;
+ }
+
+ char buf[512];
+ if (!frame->func_name.empty() && frame->func_offset) {
+ snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s+%" PRIuPTR ")",
+ frame->num, (int)sizeof(uintptr_t)*2, relative_pc, map_name,
+ frame->func_name.c_str(), frame->func_offset);
+ } else if (!frame->func_name.empty()) {
+ snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s)", frame->num,
+ (int)sizeof(uintptr_t)*2, relative_pc, map_name, frame->func_name.c_str());
+ } else {
+ snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s", frame->num,
+ (int)sizeof(uintptr_t)*2, relative_pc, map_name);
+ }
+
+ return buf;
+}
+
+const backtrace_map_t* Backtrace::FindMap(uintptr_t pc) {
+ return map_->Find(pc);
+}
+
+//-------------------------------------------------------------------------
+// BacktraceCurrent functions.
+//-------------------------------------------------------------------------
+BacktraceCurrent::BacktraceCurrent(
+ BacktraceImpl* impl, BacktraceMap* map) : Backtrace(impl, getpid(), map) {
+}
+
+BacktraceCurrent::~BacktraceCurrent() {
+}
+
+bool BacktraceCurrent::ReadWord(uintptr_t ptr, uint32_t* out_value) {
+ if (!VerifyReadWordArgs(ptr, out_value)) {
+ return false;
+ }
+
+ const backtrace_map_t* map = FindMap(ptr);
+ if (map && map->flags & PROT_READ) {
+ *out_value = *reinterpret_cast<uint32_t*>(ptr);
+ return true;
+ } else {
+ BACK_LOGW("pointer %p not in a readable map", reinterpret_cast<void*>(ptr));
+ *out_value = static_cast<uint32_t>(-1);
+ return false;
+ }
+}
+
+//-------------------------------------------------------------------------
+// BacktracePtrace functions.
+//-------------------------------------------------------------------------
+BacktracePtrace::BacktracePtrace(
+ BacktraceImpl* impl, pid_t pid, pid_t tid, BacktraceMap* map)
+ : Backtrace(impl, pid, map) {
+ tid_ = tid;
+}
+
+BacktracePtrace::~BacktracePtrace() {
+}
+
+bool BacktracePtrace::ReadWord(uintptr_t ptr, uint32_t* out_value) {
+ if (!VerifyReadWordArgs(ptr, out_value)) {
+ return false;
+ }
+
+#if defined(__APPLE__)
+ BACK_LOGW("MacOS does not support reading from another pid.");
+ return false;
+#else
+ // ptrace() returns -1 and sets errno when the operation fails.
+ // To disambiguate -1 from a valid result, we clear errno beforehand.
+ errno = 0;
+ *out_value = ptrace(PTRACE_PEEKTEXT, Tid(), reinterpret_cast<void*>(ptr), NULL);
+ if (*out_value == static_cast<uint32_t>(-1) && errno) {
+ BACK_LOGW("invalid pointer %p reading from tid %d, ptrace() strerror(errno)=%s",
+ reinterpret_cast<void*>(ptr), Tid(), strerror(errno));
+ return false;
+ }
+ return true;
+#endif
+}
+
+Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) {
+ if (pid == BACKTRACE_CURRENT_PROCESS || pid == getpid()) {
+ if (tid == BACKTRACE_CURRENT_THREAD || tid == gettid()) {
+ return CreateCurrentObj(map);
+ } else {
+ return CreateThreadObj(tid, map);
+ }
+ } else if (tid == BACKTRACE_CURRENT_THREAD) {
+ return CreatePtraceObj(pid, pid, map);
+ } else {
+ return CreatePtraceObj(pid, tid, map);
+ }
+}