commit 08c3bcd66dc0101720da78c1d5f49230f4521c75
author Jan Voung <jvoung@chromium.org> Mon Dec 01 17:55:16 2014 -0800
committer Jan Voung <jvoung@chromium.org> Mon Dec 01 17:55:16 2014 -0800
tree 290fea00c6e1ab92349db3e80f10ac876e0f364f
parent 2f6f8605b944b17a307425a81013b51b5a00a1d3

Subzero: Add basic ELFObjectWriter (text section, symtab, strtab, headers).

Able to write out the ELF file header w/ a text section,
a symbol table, and string table. Write text buffer
directly to file after translating each CFG.
This means that the header is written out early w/ fake
data and then we seek back and write the real header
at the very end.

Does not yet handle relocations, data, rodata, constant
pools, bss, or -ffunction-sections, more than 64K sections
or more than 2^24 symbols.

Numbers w/ current NOASSERT=1 build on 176.gcc:

w/out -elf-writer:
    0.233771 (21.1%): [ 1287] emit
    28MB .s file

w/ -elf-writer:
    0.051056 ( 5.6%): [ 1287] emit
    2.4MB .o file

BUG=none
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/678533005

src/assembler.cpp

diff --git a/src/assembler.cpp b/src/assembler.cpp
index b0bd297..a9516e8 100644
--- a/src/assembler.cpp
+++ b/src/assembler.cpp
@@ -20,7 +20,6 @@
 
 #include "assembler.h"
 #include "IceGlobalContext.h"
-#include "IceMemoryRegion.h"
 #include "IceOperand.h"
 
 namespace Ice {
@@ -76,25 +75,6 @@
 
 AssemblerBuffer::~AssemblerBuffer() {}
 
-void AssemblerBuffer::ProcessFixups(const MemoryRegion &region) {
-  for (SizeT I = 0; I < fixups_.size(); ++I) {
-    AssemblerFixup *fixup = fixups_[I];
-    fixup->Process(region, fixup->position());
-  }
-}
-
-void AssemblerBuffer::FinalizeInstructions(const MemoryRegion &instructions) {
-  // Copy the instructions from the buffer.
-  MemoryRegion from(reinterpret_cast<void *>(contents()), Size());
-  instructions.CopyFrom(0, from);
-
-  // Process fixups in the instructions.
-  ProcessFixups(instructions);
-#ifndef NDEBUG
-  fixups_processed_ = true;
-#endif // !NDEBUG
-}
-
 void AssemblerBuffer::ExtendCapacity() {
   intptr_t old_size = Size();
   intptr_t old_capacity = Capacity();
@@ -123,6 +103,11 @@
   assert(Size() == old_size);
 }
 
+llvm::StringRef Assembler::getBufferView() const {
+  return llvm::StringRef(reinterpret_cast<const char *>(buffer_.contents()),
+                         buffer_.Size());
+}
+
 void Assembler::emitIASBytes(GlobalContext *Ctx) const {
   Ostream &Str = Ctx->getStrEmit();
   intptr_t EndPosition = buffer_.Size();