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

1 files changed, 183 insertions, 39 deletions

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 @@ static uint8_t MakeStInfo(uint8_t binding, uint8_t type) {
   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 @@ void ElfWriterQuick::ReservePatchSpace(std::vector<uint8_t>* buffer, bool debug)
   }
 }
 
+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 @@ bool ElfWriterQuick::Write(OatWriter* oat_writer,
   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);
-  }
-}
 
-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;
-}
+    // 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 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);
-}
+  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 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,