[llvm-commits] [llvm] r72906 - in /llvm/trunk/lib/CodeGen: ELFCodeEmitter.cpp ELFCodeEmitter.h ELFWriter.h
Bruno Cardoso Lopes
bruno.cardoso at gmail.com
Thu Jun 4 17:22:12 PDT 2009
Author: bruno
Date: Thu Jun 4 19:22:10 2009
New Revision: 72906
URL: http://llvm.org/viewvc/llvm-project?rev=72906&view=rev
Log:
ELF Code Emitter now uses CurBufferPtr, BufferBegin and BufferEnd, as do JIT and
MachO Writer. This will change with the arrival of ObjectCodeEmitter and
BinaryObject
Modified:
llvm/trunk/lib/CodeGen/ELFCodeEmitter.cpp
llvm/trunk/lib/CodeGen/ELFCodeEmitter.h
llvm/trunk/lib/CodeGen/ELFWriter.h
Modified: llvm/trunk/lib/CodeGen/ELFCodeEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ELFCodeEmitter.cpp?rev=72906&r1=72905&r2=72906&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ELFCodeEmitter.cpp (original)
+++ llvm/trunk/lib/CodeGen/ELFCodeEmitter.cpp Thu Jun 4 19:22:10 2009
@@ -7,17 +7,17 @@
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "elfce"
+
#include "ELFCodeEmitter.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
-#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Support/Mangler.h"
-#include "llvm/Support/OutputBuffer.h"
+#include "llvm/Support/Debug.h"
//===----------------------------------------------------------------------===//
// ELFCodeEmitter Implementation
@@ -27,39 +27,54 @@
/// startFunction - This callback is invoked when a new machine function is
/// about to be emitted.
-void ELFCodeEmitter::startFunction(MachineFunction &F) {
- // Align the output buffer to the appropriate alignment.
- unsigned Align = 16; // FIXME: GENERICIZE!!
+void ELFCodeEmitter::startFunction(MachineFunction &MF) {
+ const TargetData *TD = TM.getTargetData();
+ const Function *F = MF.getFunction();
+
+ // Align the output buffer to the appropriate alignment, power of 2.
+ unsigned FnAlign = F->getAlignment();
+ unsigned TDAlign = TD->getPrefTypeAlignment(F->getType());
+ unsigned Align = std::max(FnAlign, TDAlign);
+ assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
+
// Get the ELF Section that this function belongs in.
- ES = &EW.getSection(".text", ELFWriter::ELFSection::SHT_PROGBITS,
- ELFWriter::ELFSection::SHF_EXECINSTR |
- ELFWriter::ELFSection::SHF_ALLOC);
- OutBuffer = &ES->SectionData;
- cerr << "FIXME: This code needs to be updated for changes in the "
- << "CodeEmitter interfaces. In particular, this should set "
- << "BufferBegin/BufferEnd/CurBufferPtr, not deal with OutBuffer!";
- abort();
+ ES = &EW.getTextSection();
+
+ // FIXME: better memory management, this will be replaced by BinaryObjects
+ ES->SectionData.reserve(4096);
+ BufferBegin = &ES->SectionData[0];
+ BufferEnd = BufferBegin + ES->SectionData.capacity();
// Upgrade the section alignment if required.
if (ES->Align < Align) ES->Align = Align;
- // Add padding zeros to the end of the buffer to make sure that the
- // function will start on the correct byte alignment within the section.
- OutputBuffer OB(*OutBuffer,
- TM.getTargetData()->getPointerSizeInBits() == 64,
- TM.getTargetData()->isLittleEndian());
- OB.align(Align);
- FnStart = OutBuffer->size();
+ // Round the size up to the correct alignment for starting the new function.
+ ES->Size = (ES->Size + (Align-1)) & (-Align);
+
+ // Snaity check on allocated space for text section
+ assert( ES->Size < 4096 && "no more space in TextSection" );
+
+ // FIXME: Using ES->Size directly here instead of calculating it from the
+ // output buffer size (impossible because the code emitter deals only in raw
+ // bytes) forces us to manually synchronize size and write padding zero bytes
+ // to the output buffer for all non-text sections. For text sections, we do
+ // not synchonize the output buffer, and we just blow up if anyone tries to
+ // write non-code to it. An assert should probably be added to
+ // AddSymbolToSection to prevent calling it on the text section.
+ CurBufferPtr = BufferBegin + ES->Size;
+
+ // Record function start address relative to BufferBegin
+ FnStartPtr = CurBufferPtr;
}
/// finishFunction - This callback is invoked after the function is completely
/// finished.
-bool ELFCodeEmitter::finishFunction(MachineFunction &F) {
- // We now know the size of the function, add a symbol to represent it.
- ELFWriter::ELFSym FnSym(F.getFunction());
+bool ELFCodeEmitter::finishFunction(MachineFunction &MF) {
+ // Add a symbol to represent the function.
+ ELFWriter::ELFSym FnSym(MF.getFunction());
// Figure out the binding (linkage) of the symbol.
- switch (F.getFunction()->getLinkage()) {
+ switch (MF.getFunction()->getLinkage()) {
default:
// appending linkage is illegal for functions.
assert(0 && "Unknown linkage type!");
@@ -79,15 +94,20 @@
break;
}
- ES->Size = OutBuffer->size();
-
+ // Set the symbol type as a function
FnSym.SetType(ELFWriter::ELFSym::STT_FUNC);
+
FnSym.SectionIdx = ES->SectionIdx;
- FnSym.Value = FnStart; // Value = Offset from start of Section.
- FnSym.Size = OutBuffer->size()-FnStart;
+ FnSym.Size = CurBufferPtr-FnStartPtr;
+
+ // Offset from start of Section
+ FnSym.Value = FnStartPtr-BufferBegin;
// Finally, add it to the symtab.
EW.SymbolTable.push_back(FnSym);
+
+ // Update Section Size
+ ES->Size = CurBufferPtr - BufferBegin;
return false;
}
Modified: llvm/trunk/lib/CodeGen/ELFCodeEmitter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ELFCodeEmitter.h?rev=72906&r1=72905&r2=72906&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ELFCodeEmitter.h (original)
+++ llvm/trunk/lib/CodeGen/ELFCodeEmitter.h Thu Jun 4 19:22:10 2009
@@ -22,10 +22,9 @@
ELFWriter &EW;
TargetMachine &TM;
ELFWriter::ELFSection *ES; // Section to write to.
- std::vector<unsigned char> *OutBuffer;
- size_t FnStart;
+ uint8_t *FnStartPtr;
public:
- explicit ELFCodeEmitter(ELFWriter &ew) : EW(ew), TM(EW.TM), OutBuffer(0) {}
+ explicit ELFCodeEmitter(ELFWriter &ew) : EW(ew), TM(EW.TM) {}
void startFunction(MachineFunction &F);
bool finishFunction(MachineFunction &F);
Modified: llvm/trunk/lib/CodeGen/ELFWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ELFWriter.h?rev=72906&r1=72905&r2=72906&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ELFWriter.h (original)
+++ llvm/trunk/lib/CodeGen/ELFWriter.h Thu Jun 4 19:22:10 2009
@@ -168,6 +168,12 @@
return *SN;
}
+ ELFSection &getTextSection() {
+ return getSection(".text", ELFWriter::ELFSection::SHT_PROGBITS,
+ ELFWriter::ELFSection::SHF_EXECINSTR |
+ ELFWriter::ELFSection::SHF_ALLOC);
+ }
+
ELFSection &getDataSection() {
return getSection(".data", ELFSection::SHT_PROGBITS,
ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC);
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