commit 527c9c71f0c6e2f9943ac028e7c050500699a44b
author David Srbecky <dsrbecky@google.com> Fri Apr 17 21:14:10 2015 +0100
committer David Srbecky <dsrbecky@google.com> Tue Apr 21 19:47:42 2015 +0100
tree 09e6794e5b184ce33ca468c972a8ef2faff7f174
parent e7bee3b7d307508243f4a00b5cf8a8867fcaaff5

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

compiler/dwarf/dwarf_test.cc

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);