ART: Rework CFA frame initialization and writing code
Move eh_frame initialization code and CFI writing code to
elf_writer_quick to remove hard-wired dependencies on specific
Quick-compiler backends.
Change-Id: I27ee8ce7245da33a20c90e0086b8d4fd0a2baf4d
diff --git a/compiler/elf_writer_quick.cc b/compiler/elf_writer_quick.cc
index 1fde12e..71f02d3 100644
--- a/compiler/elf_writer_quick.cc
+++ b/compiler/elf_writer_quick.cc
@@ -24,6 +24,7 @@
#include "elf_utils.h"
#include "file_output_stream.h"
#include "globals.h"
+#include "leb128.h"
#include "oat.h"
#include "oat_writer.h"
#include "utils.h"
@@ -38,6 +39,25 @@
return ((binding) << 4) + ((type) & 0xf);
}
+static void UpdateWord(std::vector<uint8_t>* buf, int offset, int data) {
+ (*buf)[offset+0] = data;
+ (*buf)[offset+1] = data >> 8;
+ (*buf)[offset+2] = data >> 16;
+ (*buf)[offset+3] = data >> 24;
+}
+
+static void PushWord(std::vector<uint8_t>* buf, int data) {
+ buf->push_back(data & 0xff);
+ buf->push_back((data >> 8) & 0xff);
+ buf->push_back((data >> 16) & 0xff);
+ buf->push_back((data >> 24) & 0xff);
+}
+
+static void PushHalf(std::vector<uint8_t>* buf, int data) {
+ buf->push_back(data & 0xff);
+ buf->push_back((data >> 8) & 0xff);
+}
+
bool ElfWriterQuick::ElfBuilder::Write() {
// The basic layout of the elf file. Order may be different in final output.
// +-------------------------+
@@ -822,37 +842,131 @@
}
}
+static void EncodeUnsignedLeb128(uint32_t data, std::vector<uint8_t>* dst) {
+ size_t encoded_size = UnsignedLeb128Size(data);
+ size_t cur_index = dst->size();
+ dst->resize(dst->size() + encoded_size);
+ uint8_t* write_pos = &((*dst)[cur_index]);
+ uint8_t* write_pos_after = EncodeUnsignedLeb128(write_pos, data);
+ DCHECK_EQ(static_cast<size_t>(write_pos_after - write_pos), encoded_size);
+}
+
+static void EncodeSignedLeb128(int32_t data, std::vector<uint8_t>* dst) {
+ size_t encoded_size = SignedLeb128Size(data);
+ size_t cur_index = dst->size();
+ dst->resize(dst->size() + encoded_size);
+ uint8_t* write_pos = &((*dst)[cur_index]);
+ uint8_t* write_pos_after = EncodeSignedLeb128(write_pos, data);
+ DCHECK_EQ(static_cast<size_t>(write_pos_after - write_pos), encoded_size);
+}
+
+std::vector<uint8_t>* ConstructCIEFrameX86(bool is_x86_64) {
+ std::vector<uint8_t>*cfi_info = new std::vector<uint8_t>;
+
+ // Length (will be filled in later in this routine).
+ PushWord(cfi_info, 0);
+
+ // CIE id: always 0.
+ PushWord(cfi_info, 0);
+
+ // Version: always 1.
+ cfi_info->push_back(0x01);
+
+ // Augmentation: 'zR\0'
+ cfi_info->push_back(0x7a);
+ cfi_info->push_back(0x52);
+ cfi_info->push_back(0x0);
+
+ // Code alignment: 1.
+ EncodeUnsignedLeb128(1, cfi_info);
+
+ // Data alignment.
+ if (is_x86_64) {
+ EncodeSignedLeb128(-8, cfi_info);
+ } else {
+ EncodeSignedLeb128(-4, cfi_info);
+ }
+
+ // Return address register.
+ if (is_x86_64) {
+ // R16(RIP)
+ cfi_info->push_back(0x10);
+ } else {
+ // R8(EIP)
+ cfi_info->push_back(0x08);
+ }
+
+ // Augmentation length: 1.
+ cfi_info->push_back(1);
+
+ // Augmentation data: 0x03 ((DW_EH_PE_absptr << 4) | DW_EH_PE_udata4).
+ cfi_info->push_back(0x03);
+
+ // Initial instructions.
+ if (is_x86_64) {
+ // DW_CFA_def_cfa R7(RSP) 8.
+ cfi_info->push_back(0x0c);
+ cfi_info->push_back(0x07);
+ cfi_info->push_back(0x08);
+
+ // DW_CFA_offset R16(RIP) 1 (* -8).
+ cfi_info->push_back(0x90);
+ cfi_info->push_back(0x01);
+ } else {
+ // DW_CFA_def_cfa R4(ESP) 4.
+ cfi_info->push_back(0x0c);
+ cfi_info->push_back(0x04);
+ cfi_info->push_back(0x04);
+
+ // DW_CFA_offset R8(EIP) 1 (* -4).
+ cfi_info->push_back(0x88);
+ cfi_info->push_back(0x01);
+ }
+
+ // Padding to a multiple of 4
+ while ((cfi_info->size() & 3) != 0) {
+ // DW_CFA_nop is encoded as 0.
+ cfi_info->push_back(0);
+ }
+
+ // Set the length of the CIE inside the generated bytes.
+ uint32_t length = cfi_info->size() - 4;
+ (*cfi_info)[0] = length;
+ (*cfi_info)[1] = length >> 8;
+ (*cfi_info)[2] = length >> 16;
+ (*cfi_info)[3] = length >> 24;
+ return cfi_info;
+}
+
+std::vector<uint8_t>* ConstructCIEFrame(InstructionSet isa) {
+ switch (isa) {
+ case kX86:
+ return ConstructCIEFrameX86(false);
+ case kX86_64:
+ return ConstructCIEFrameX86(true);
+
+ default:
+ // Not implemented.
+ return nullptr;
+ }
+}
+
bool ElfWriterQuick::Write(OatWriter* oat_writer,
const std::vector<const DexFile*>& dex_files_unused,
const std::string& android_root_unused,
bool is_host_unused) {
- const bool debug = false;
- const bool add_symbols = oat_writer->DidAddSymbols();
+ constexpr bool debug = false;
const OatHeader& oat_header = oat_writer->GetOatHeader();
Elf32_Word oat_data_size = oat_header.GetExecutableOffset();
uint32_t oat_exec_size = oat_writer->GetSize() - oat_data_size;
ElfBuilder builder(oat_writer, elf_file_, compiler_driver_->GetInstructionSet(), 0,
- oat_data_size, oat_data_size, oat_exec_size, add_symbols, debug);
+ oat_data_size, oat_data_size, oat_exec_size,
+ compiler_driver_->GetCompilerOptions().GetIncludeDebugSymbols(),
+ debug);
- if (add_symbols) {
- AddDebugSymbols(builder, oat_writer, debug);
- }
-
- bool generateDebugInformation = compiler_driver_->GetCallFrameInformation() != nullptr;
- if (generateDebugInformation) {
- ElfRawSectionBuilder debug_info(".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
- ElfRawSectionBuilder debug_abbrev(".debug_abbrev", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
- ElfRawSectionBuilder debug_str(".debug_str", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
- ElfRawSectionBuilder eh_frame(".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0);
- eh_frame.SetBuffer(*compiler_driver_->GetCallFrameInformation());
-
- FillInCFIInformation(oat_writer, debug_info.GetBuffer(),
- debug_abbrev.GetBuffer(), debug_str.GetBuffer());
- builder.RegisterRawSection(debug_info);
- builder.RegisterRawSection(debug_abbrev);
- builder.RegisterRawSection(eh_frame);
- builder.RegisterRawSection(debug_str);
+ if (compiler_driver_->GetCompilerOptions().GetIncludeDebugSymbols()) {
+ WriteDebugSymbols(builder, oat_writer);
}
if (compiler_driver_->GetCompilerOptions().GetIncludePatchInformation()) {
@@ -865,32 +979,62 @@
return builder.Write();
}
-void ElfWriterQuick::AddDebugSymbols(ElfBuilder& builder, OatWriter* oat_writer, bool debug) {
+void ElfWriterQuick::WriteDebugSymbols(ElfBuilder& builder, OatWriter* oat_writer) {
+ std::unique_ptr<std::vector<uint8_t>> cfi_info(
+ ConstructCIEFrame(compiler_driver_->GetInstructionSet()));
+
+ // Iterate over the compiled methods.
const std::vector<OatWriter::DebugInfo>& method_info = oat_writer->GetCFIMethodInfo();
ElfSymtabBuilder* symtab = &builder.symtab_builder_;
for (auto it = method_info.begin(); it != method_info.end(); ++it) {
symtab->AddSymbol(it->method_name_, &builder.text_builder_, it->low_pc_, true,
it->high_pc_ - it->low_pc_, STB_GLOBAL, STT_FUNC);
+
+ // Include CFI for compiled method, if possible.
+ if (cfi_info.get() != nullptr) {
+ DCHECK(it->compiled_method_ != nullptr);
+
+ // Copy in the FDE, if present
+ const std::vector<uint8_t>* fde = it->compiled_method_->GetCFIInfo();
+ if (fde != nullptr) {
+ // Copy the information into cfi_info and then fix the address in the new copy.
+ int cur_offset = cfi_info->size();
+ cfi_info->insert(cfi_info->end(), fde->begin(), fde->end());
+
+ // Set the 'CIE_pointer' field to cur_offset+4.
+ uint32_t CIE_pointer = cur_offset + 4;
+ uint32_t offset_to_update = cur_offset + sizeof(uint32_t);
+ (*cfi_info)[offset_to_update+0] = CIE_pointer;
+ (*cfi_info)[offset_to_update+1] = CIE_pointer >> 8;
+ (*cfi_info)[offset_to_update+2] = CIE_pointer >> 16;
+ (*cfi_info)[offset_to_update+3] = CIE_pointer >> 24;
+
+ // Set the 'initial_location' field to address the start of the method.
+ offset_to_update = cur_offset + 2*sizeof(uint32_t);
+ const uint32_t quick_code_start = it->low_pc_;
+ (*cfi_info)[offset_to_update+0] = quick_code_start;
+ (*cfi_info)[offset_to_update+1] = quick_code_start >> 8;
+ (*cfi_info)[offset_to_update+2] = quick_code_start >> 16;
+ (*cfi_info)[offset_to_update+3] = quick_code_start >> 24;
+ }
+ }
}
-}
-static void UpdateWord(std::vector<uint8_t>*buf, int offset, int data) {
- (*buf)[offset+0] = data;
- (*buf)[offset+1] = data >> 8;
- (*buf)[offset+2] = data >> 16;
- (*buf)[offset+3] = data >> 24;
-}
+ if (cfi_info.get() != nullptr) {
+ // Now lay down the Elf sections.
+ ElfRawSectionBuilder debug_info(".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ ElfRawSectionBuilder debug_abbrev(".debug_abbrev", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ ElfRawSectionBuilder debug_str(".debug_str", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ ElfRawSectionBuilder eh_frame(".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0);
+ eh_frame.SetBuffer(std::move(*cfi_info.get()));
-static void PushWord(std::vector<uint8_t>*buf, int data) {
- buf->push_back(data & 0xff);
- buf->push_back((data >> 8) & 0xff);
- buf->push_back((data >> 16) & 0xff);
- buf->push_back((data >> 24) & 0xff);
-}
-
-static void PushHalf(std::vector<uint8_t>*buf, int data) {
- buf->push_back(data & 0xff);
- buf->push_back((data >> 8) & 0xff);
+ FillInCFIInformation(oat_writer, debug_info.GetBuffer(), debug_abbrev.GetBuffer(),
+ debug_str.GetBuffer());
+ builder.RegisterRawSection(debug_info);
+ builder.RegisterRawSection(debug_abbrev);
+ builder.RegisterRawSection(eh_frame);
+ builder.RegisterRawSection(debug_str);
+ }
}
void ElfWriterQuick::FillInCFIInformation(OatWriter* oat_writer,