Elf interface for new unwinder.
This cl includes the code to read arm unwind information from a shared
library.
Bug: 23762183
Test: Passes all unit tests. I can dump the arm unwind information
Test: for an arm shared library.
Change-Id: I43501ea2eab843b81de8bd5128401dd1971af8d3
diff --git a/libunwindstack/Regs.cpp b/libunwindstack/Regs.cpp
new file mode 100644
index 0000000..adb6522
--- /dev/null
+++ b/libunwindstack/Regs.cpp
@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2016 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 <assert.h>
+#include <elf.h>
+#include <stdint.h>
+#include <sys/ptrace.h>
+#include <sys/uio.h>
+
+#include <vector>
+
+#include "Elf.h"
+#include "ElfInterface.h"
+#include "Machine.h"
+#include "MapInfo.h"
+#include "Regs.h"
+#include "User.h"
+
+template <typename AddressType>
+uint64_t RegsTmpl<AddressType>::GetRelPc(Elf* elf, const MapInfo* map_info) {
+ uint64_t load_bias = 0;
+ if (elf->valid()) {
+ load_bias = elf->interface()->load_bias();
+ }
+
+ return pc_ - map_info->start + load_bias + map_info->elf_offset;
+}
+
+template <typename AddressType>
+bool RegsTmpl<AddressType>::GetReturnAddressFromDefault(Memory* memory, uint64_t* value) {
+ switch (return_loc_.type) {
+ case LOCATION_REGISTER:
+ assert(return_loc_.value < total_regs_);
+ *value = regs_[return_loc_.value];
+ return true;
+ case LOCATION_SP_OFFSET:
+ AddressType return_value;
+ if (!memory->Read(sp_ + return_loc_.value, &return_value, sizeof(return_value))) {
+ return false;
+ }
+ *value = return_value;
+ return true;
+ case LOCATION_UNKNOWN:
+ default:
+ return false;
+ }
+}
+
+RegsArm::RegsArm() : RegsTmpl<uint32_t>(ARM_REG_LAST, ARM_REG_SP,
+ Location(LOCATION_REGISTER, ARM_REG_LR)) {
+}
+
+uint64_t RegsArm::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
+ if (!elf->valid()) {
+ return rel_pc;
+ }
+
+ uint64_t load_bias = elf->interface()->load_bias();
+ if (rel_pc < load_bias) {
+ return rel_pc;
+ }
+ uint64_t adjusted_rel_pc = rel_pc - load_bias;
+
+ if (adjusted_rel_pc < 5) {
+ return rel_pc;
+ }
+
+ if (adjusted_rel_pc & 1) {
+ // This is a thumb instruction, it could be 2 or 4 bytes.
+ uint32_t value;
+ if (rel_pc < 5 || !elf->memory()->Read(adjusted_rel_pc - 5, &value, sizeof(value)) ||
+ (value & 0xe000f000) != 0xe000f000) {
+ return rel_pc - 2;
+ }
+ }
+ return rel_pc - 4;
+}
+
+RegsArm64::RegsArm64() : RegsTmpl<uint64_t>(ARM64_REG_LAST, ARM64_REG_SP,
+ Location(LOCATION_REGISTER, ARM64_REG_LR)) {
+}
+
+uint64_t RegsArm64::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
+ if (!elf->valid()) {
+ return rel_pc;
+ }
+
+ if (rel_pc < 4) {
+ return rel_pc;
+ }
+ return rel_pc - 4;
+}
+
+RegsX86::RegsX86() : RegsTmpl<uint32_t>(X86_REG_LAST, X86_REG_SP,
+ Location(LOCATION_SP_OFFSET, -4)) {
+}
+
+uint64_t RegsX86::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
+ if (!elf->valid()) {
+ return rel_pc;
+ }
+
+ if (rel_pc == 0) {
+ return 0;
+ }
+ return rel_pc - 1;
+}
+
+RegsX86_64::RegsX86_64() : RegsTmpl<uint64_t>(X86_64_REG_LAST, X86_64_REG_SP,
+ Location(LOCATION_SP_OFFSET, -8)) {
+}
+
+uint64_t RegsX86_64::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
+ if (!elf->valid()) {
+ return rel_pc;
+ }
+
+ if (rel_pc == 0) {
+ return 0;
+ }
+
+ return rel_pc - 1;
+}
+
+static Regs* ReadArm(void* remote_data) {
+ arm_user_regs* user = reinterpret_cast<arm_user_regs*>(remote_data);
+
+ RegsArm* regs = new RegsArm();
+ memcpy(regs->RawData(), &user->regs[0], ARM_REG_LAST * sizeof(uint32_t));
+
+ regs->set_pc(user->regs[ARM_REG_PC]);
+ regs->set_sp(user->regs[ARM_REG_SP]);
+
+ return regs;
+}
+
+static Regs* ReadArm64(void* remote_data) {
+ arm64_user_regs* user = reinterpret_cast<arm64_user_regs*>(remote_data);
+
+ RegsArm64* regs = new RegsArm64();
+ memcpy(regs->RawData(), &user->regs[0], (ARM64_REG_R31 + 1) * sizeof(uint64_t));
+ regs->set_pc(user->pc);
+ regs->set_sp(user->sp);
+
+ return regs;
+}
+
+static Regs* ReadX86(void* remote_data) {
+ x86_user_regs* user = reinterpret_cast<x86_user_regs*>(remote_data);
+
+ RegsX86* regs = new RegsX86();
+ (*regs)[X86_REG_EAX] = user->eax;
+ (*regs)[X86_REG_EBX] = user->ebx;
+ (*regs)[X86_REG_ECX] = user->ecx;
+ (*regs)[X86_REG_EDX] = user->edx;
+ (*regs)[X86_REG_EBP] = user->ebp;
+ (*regs)[X86_REG_EDI] = user->edi;
+ (*regs)[X86_REG_ESI] = user->esi;
+ (*regs)[X86_REG_ESP] = user->esp;
+ (*regs)[X86_REG_EIP] = user->eip;
+
+ regs->set_pc(user->eip);
+ regs->set_sp(user->esp);
+
+ return regs;
+}
+
+static Regs* ReadX86_64(void* remote_data) {
+ x86_64_user_regs* user = reinterpret_cast<x86_64_user_regs*>(remote_data);
+
+ RegsX86_64* regs = new RegsX86_64();
+ (*regs)[X86_64_REG_RAX] = user->rax;
+ (*regs)[X86_64_REG_RBX] = user->rbx;
+ (*regs)[X86_64_REG_RCX] = user->rcx;
+ (*regs)[X86_64_REG_RDX] = user->rdx;
+ (*regs)[X86_64_REG_R8] = user->r8;
+ (*regs)[X86_64_REG_R9] = user->r9;
+ (*regs)[X86_64_REG_R10] = user->r10;
+ (*regs)[X86_64_REG_R11] = user->r11;
+ (*regs)[X86_64_REG_R12] = user->r12;
+ (*regs)[X86_64_REG_R13] = user->r13;
+ (*regs)[X86_64_REG_R14] = user->r14;
+ (*regs)[X86_64_REG_R15] = user->r15;
+ (*regs)[X86_64_REG_RDI] = user->rdi;
+ (*regs)[X86_64_REG_RSI] = user->rsi;
+ (*regs)[X86_64_REG_RBP] = user->rbp;
+ (*regs)[X86_64_REG_RSP] = user->rsp;
+ (*regs)[X86_64_REG_RIP] = user->rip;
+
+ regs->set_pc(user->rip);
+ regs->set_sp(user->rsp);
+
+ return regs;
+}
+
+// This function assumes that reg_data is already aligned to a 64 bit value.
+// If not this could crash with an unaligned access.
+Regs* Regs::RemoteGet(pid_t pid, uint32_t* machine_type) {
+ // Make the buffer large enough to contain the largest registers type.
+ std::vector<uint64_t> buffer(MAX_USER_REGS_SIZE / sizeof(uint64_t));
+ struct iovec io;
+ io.iov_base = buffer.data();
+ io.iov_len = buffer.size() * sizeof(uint64_t);
+
+ if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, reinterpret_cast<void*>(&io)) == -1) {
+ return nullptr;
+ }
+
+ switch (io.iov_len) {
+ case sizeof(x86_user_regs):
+ *machine_type = EM_386;
+ return ReadX86(buffer.data());
+ case sizeof(x86_64_user_regs):
+ *machine_type = EM_X86_64;
+ return ReadX86_64(buffer.data());
+ case sizeof(arm_user_regs):
+ *machine_type = EM_ARM;
+ return ReadArm(buffer.data());
+ case sizeof(arm64_user_regs):
+ *machine_type = EM_AARCH64;
+ return ReadArm64(buffer.data());
+ }
+ return nullptr;
+}