Relocate DWARF using .oat_patches.
The current solution is to hard-code knowledge of DWARF in the linker.
This works for simple use of DWARF, but breaks as soon as I try to do
anything more complex. Making the linker fully support DWARF would be
non-trivial task and would be essentially rewrite. Using .oat_patches
is much easier solution.
Relocating .debug_* sections required extending .oat_patches to support
more sections than just .text. I have encoded each section as
null-terminated section name followed by ULEB128 deltas.
The ULEB128 encoding shrinks .oat_patches for .text by factor of
about 6 with 64-bit compiler, and factor of 3 with 32-bit compiler.
On the other hand, it grows by the extra .oat_patches for DWARF which
were not present before (if debug symbols are included).
Overall, it is still a clear improvement even with the DWARF patches.
Change-Id: I78ffeda0f8a3da03341995a3b5ef15c954e16e9f
diff --git a/compiler/dwarf/debug_line_opcode_writer.h b/compiler/dwarf/debug_line_opcode_writer.h
index f34acee..77ed154 100644
--- a/compiler/dwarf/debug_line_opcode_writer.h
+++ b/compiler/dwarf/debug_line_opcode_writer.h
@@ -17,6 +17,8 @@
#ifndef ART_COMPILER_DWARF_DEBUG_LINE_OPCODE_WRITER_H_
#define ART_COMPILER_DWARF_DEBUG_LINE_OPCODE_WRITER_H_
+#include <cstdint>
+
#include "dwarf.h"
#include "writer.h"
@@ -119,10 +121,12 @@
if (use_64bit_address_) {
this->PushUleb128(1 + 8);
this->PushUint8(DW_LNE_set_address);
+ patch_locations_.push_back(this->data()->size());
this->PushUint64(absolute_address);
} else {
this->PushUleb128(1 + 4);
this->PushUint8(DW_LNE_set_address);
+ patch_locations_.push_back(this->data()->size());
this->PushUint32(absolute_address);
}
current_address_ = absolute_address;
@@ -204,6 +208,10 @@
return current_line_;
}
+ const std::vector<uintptr_t>& GetPatchLocations() const {
+ return patch_locations_;
+ }
+
using Writer<Allocator>::data;
DebugLineOpCodeWriter(bool use64bitAddress,
@@ -233,6 +241,7 @@
uint64_t current_address_;
int current_file_;
int current_line_;
+ std::vector<uintptr_t> patch_locations_;
DISALLOW_COPY_AND_ASSIGN(DebugLineOpCodeWriter);
};