Generate .eh_frame_hdr section and PT_GNU_EH_FRAME segment.
Fixes issue 20125400 - ART: Need .eh_frame_hdr and PT_GNU_EH_FRAME
for libunwind.
.eh_frame_hdr serves two purposes. Firstly, it can optionally contain
binary search table for fast eh_frame lookup. This is important for
C++ exception handling, but we do not need it so we omit it.
Secondly, it contains a relative .eh_frame pointer which makes it
easier for run-time code to locate the .eh_frame section.
libunwind seems to rely on this relative pointer.
Bug: 20125400
Change-Id: I7c1e3f68d914f70781404c508395831a3296a7da
diff --git a/compiler/dwarf/dwarf_constants.h b/compiler/dwarf/dwarf_constants.h
index 8e39ca7..61a44cd 100644
--- a/compiler/dwarf/dwarf_constants.h
+++ b/compiler/dwarf/dwarf_constants.h
@@ -658,6 +658,28 @@
DW_CFA_hi_user = 0x3f
};
+enum ExceptionHeaderValueFormat : uint8_t {
+ DW_EH_PE_native = 0x00,
+ DW_EH_PE_uleb128 = 0x01,
+ DW_EH_PE_udata2 = 0x02,
+ DW_EH_PE_udata4 = 0x03,
+ DW_EH_PE_udata8 = 0x04,
+ DW_EH_PE_sleb128 = 0x09,
+ DW_EH_PE_sdata2 = 0x0A,
+ DW_EH_PE_sdata4 = 0x0B,
+ DW_EH_PE_sdata8 = 0x0C,
+ DW_EH_PE_omit = 0xFF,
+};
+
+enum ExceptionHeaderValueApplication : uint8_t {
+ DW_EH_PE_absptr = 0x00,
+ DW_EH_PE_pcrel = 0x10,
+ DW_EH_PE_textrel = 0x20,
+ DW_EH_PE_datarel = 0x30,
+ DW_EH_PE_funcrel = 0x40,
+ DW_EH_PE_aligned = 0x50,
+};
+
} // namespace dwarf
} // namespace art
diff --git a/compiler/dwarf/dwarf_test.cc b/compiler/dwarf/dwarf_test.cc
index 98f691a..edba00a 100644
--- a/compiler/dwarf/dwarf_test.cc
+++ b/compiler/dwarf/dwarf_test.cc
@@ -16,6 +16,7 @@
#include "dwarf_test.h"
+#include "dwarf/dwarf_constants.h"
#include "dwarf/debug_frame_opcode_writer.h"
#include "dwarf/debug_info_entry_writer.h"
#include "dwarf/debug_line_opcode_writer.h"
@@ -119,7 +120,8 @@
DW_CHECK_NEXT("DW_CFA_restore: r5 (ebp)");
DebugFrameOpCodeWriter<> initial_opcodes;
- WriteEhFrameCIE(is64bit, Reg(is64bit ? 16 : 8), initial_opcodes, &eh_frame_data_);
+ WriteEhFrameCIE(is64bit, DW_EH_PE_absptr, Reg(is64bit ? 16 : 8),
+ initial_opcodes, &eh_frame_data_);
std::vector<uintptr_t> eh_frame_patches;
std::vector<uintptr_t> expected_patches { 28 }; // NOLINT
WriteEhFrameFDE(is64bit, 0, 0x01000000, 0x01000000, opcodes.data(),
@@ -132,7 +134,8 @@
TEST_F(DwarfTest, DebugFrame64) {
constexpr bool is64bit = true;
DebugFrameOpCodeWriter<> initial_opcodes;
- WriteEhFrameCIE(is64bit, Reg(16), initial_opcodes, &eh_frame_data_);
+ WriteEhFrameCIE(is64bit, DW_EH_PE_absptr, Reg(16),
+ initial_opcodes, &eh_frame_data_);
DebugFrameOpCodeWriter<> opcodes;
std::vector<uintptr_t> eh_frame_patches;
std::vector<uintptr_t> expected_patches { 32 }; // NOLINT
@@ -170,7 +173,8 @@
DW_CHECK_NEXT("DW_CFA_offset: r14 (r14)");
DW_CHECK_NEXT("DW_CFA_offset: r15 (r15)");
DebugFrameOpCodeWriter<> initial_opcodes;
- WriteEhFrameCIE(is64bit, Reg(16), initial_opcodes, &eh_frame_data_);
+ WriteEhFrameCIE(is64bit, DW_EH_PE_absptr, Reg(16),
+ initial_opcodes, &eh_frame_data_);
std::vector<uintptr_t> eh_frame_patches;
WriteEhFrameFDE(is64bit, 0, 0x0100000000000000, 0x0200000000000000,
opcodes.data(), &eh_frame_data_, &eh_frame_patches);
diff --git a/compiler/dwarf/dwarf_test.h b/compiler/dwarf/dwarf_test.h
index dd5e0c2..cbe700a 100644
--- a/compiler/dwarf/dwarf_test.h
+++ b/compiler/dwarf/dwarf_test.h
@@ -100,30 +100,30 @@
Elf_Sym, Elf_Ehdr, Elf_Phdr, Elf_Shdr> builder(
&code, file.GetFile(), isa, 0, 0, 0, 0, 0, 0, false, false);
typedef ElfRawSectionBuilder<Elf_Word, Elf_Sword, Elf_Shdr> Section;
+ Section debug_info(".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ Section debug_abbrev(".debug_abbrev", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ Section debug_str(".debug_str", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ Section debug_line(".debug_line", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
+ Section eh_frame(".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0);
if (!debug_info_data_.empty()) {
- Section debug_info(".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
debug_info.SetBuffer(debug_info_data_);
- builder.RegisterRawSection(debug_info);
+ builder.RegisterRawSection(&debug_info);
}
if (!debug_abbrev_data_.empty()) {
- Section debug_abbrev(".debug_abbrev", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
debug_abbrev.SetBuffer(debug_abbrev_data_);
- builder.RegisterRawSection(debug_abbrev);
+ builder.RegisterRawSection(&debug_abbrev);
}
if (!debug_str_data_.empty()) {
- Section debug_str(".debug_str", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
debug_str.SetBuffer(debug_str_data_);
- builder.RegisterRawSection(debug_str);
+ builder.RegisterRawSection(&debug_str);
}
if (!debug_line_data_.empty()) {
- Section debug_line(".debug_line", SHT_PROGBITS, 0, nullptr, 0, 1, 0);
debug_line.SetBuffer(debug_line_data_);
- builder.RegisterRawSection(debug_line);
+ builder.RegisterRawSection(&debug_line);
}
if (!eh_frame_data_.empty()) {
- Section eh_frame(".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0);
eh_frame.SetBuffer(eh_frame_data_);
- builder.RegisterRawSection(eh_frame);
+ builder.RegisterRawSection(&eh_frame);
}
builder.Init();
builder.Write();
diff --git a/compiler/dwarf/headers.h b/compiler/dwarf/headers.h
index 760f53c..9f64766 100644
--- a/compiler/dwarf/headers.h
+++ b/compiler/dwarf/headers.h
@@ -22,6 +22,7 @@
#include "dwarf/debug_frame_opcode_writer.h"
#include "dwarf/debug_info_entry_writer.h"
#include "dwarf/debug_line_opcode_writer.h"
+#include "dwarf/dwarf_constants.h"
#include "dwarf/register.h"
#include "dwarf/writer.h"
@@ -36,7 +37,9 @@
// Write common information entry (CIE) to .eh_frame section.
template<typename Allocator>
-void WriteEhFrameCIE(bool is64bit, Reg return_address_register,
+void WriteEhFrameCIE(bool is64bit,
+ ExceptionHeaderValueApplication address_type,
+ Reg return_address_register,
const DebugFrameOpCodeWriter<Allocator>& opcodes,
std::vector<uint8_t>* eh_frame) {
Writer<> writer(eh_frame);
@@ -50,9 +53,9 @@
writer.PushUleb128(return_address_register.num()); // ubyte in DWARF2.
writer.PushUleb128(1); // z: Augmentation data size.
if (is64bit) {
- writer.PushUint8(0x04); // R: ((DW_EH_PE_absptr << 4) | DW_EH_PE_udata8).
+ writer.PushUint8(address_type | DW_EH_PE_udata8); // R: Pointer encoding.
} else {
- writer.PushUint8(0x03); // R: ((DW_EH_PE_absptr << 4) | DW_EH_PE_udata4).
+ writer.PushUint8(address_type | DW_EH_PE_udata4); // R: Pointer encoding.
}
writer.PushData(opcodes.data());
writer.Pad(is64bit ? 8 : 4);