forked from OSchip/llvm-project
124 lines
4.2 KiB
C++
124 lines
4.2 KiB
C++
//===-- ErlangGCPrinter.cpp - Erlang/OTP frametable emitter -----*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the compiler plugin that is used in order to emit
|
|
// garbage collection information in a convenient layout for parsing and
|
|
// loading in the Erlang/OTP runtime.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/CodeGen/AsmPrinter.h"
|
|
#include "llvm/CodeGen/GCMetadataPrinter.h"
|
|
#include "llvm/CodeGen/GCs.h"
|
|
#include "llvm/IR/DataLayout.h"
|
|
#include "llvm/IR/Function.h"
|
|
#include "llvm/IR/Instruction.h"
|
|
#include "llvm/IR/IntrinsicInst.h"
|
|
#include "llvm/IR/Metadata.h"
|
|
#include "llvm/MC/MCAsmInfo.h"
|
|
#include "llvm/MC/MCContext.h"
|
|
#include "llvm/MC/MCSectionELF.h"
|
|
#include "llvm/MC/MCStreamer.h"
|
|
#include "llvm/MC/MCSymbol.h"
|
|
#include "llvm/Target/TargetLoweringObjectFile.h"
|
|
#include "llvm/Target/TargetMachine.h"
|
|
#include "llvm/Target/TargetSubtargetInfo.h"
|
|
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
|
|
class ErlangGCPrinter : public GCMetadataPrinter {
|
|
public:
|
|
void finishAssembly(Module &M, GCModuleInfo &Info, AsmPrinter &AP) override;
|
|
};
|
|
}
|
|
|
|
static GCMetadataPrinterRegistry::Add<ErlangGCPrinter>
|
|
X("erlang", "erlang-compatible garbage collector");
|
|
|
|
void llvm::linkErlangGCPrinter() {}
|
|
|
|
void ErlangGCPrinter::finishAssembly(Module &M, GCModuleInfo &Info,
|
|
AsmPrinter &AP) {
|
|
MCStreamer &OS = *AP.OutStreamer;
|
|
unsigned IntPtrSize = M.getDataLayout().getPointerSize();
|
|
|
|
// Put this in a custom .note section.
|
|
OS.SwitchSection(
|
|
AP.getObjFileLowering().getContext().getELFSection(".note.gc",
|
|
ELF::SHT_PROGBITS, 0));
|
|
|
|
// For each function...
|
|
for (GCModuleInfo::FuncInfoVec::iterator FI = Info.funcinfo_begin(),
|
|
IE = Info.funcinfo_end();
|
|
FI != IE; ++FI) {
|
|
GCFunctionInfo &MD = **FI;
|
|
if (MD.getStrategy().getName() != getStrategy().getName())
|
|
// this function is managed by some other GC
|
|
continue;
|
|
/** A compact GC layout. Emit this data structure:
|
|
*
|
|
* struct {
|
|
* int16_t PointCount;
|
|
* void *SafePointAddress[PointCount];
|
|
* int16_t StackFrameSize; (in words)
|
|
* int16_t StackArity;
|
|
* int16_t LiveCount;
|
|
* int16_t LiveOffsets[LiveCount];
|
|
* } __gcmap_<FUNCTIONNAME>;
|
|
**/
|
|
|
|
// Align to address width.
|
|
AP.EmitAlignment(IntPtrSize == 4 ? 2 : 3);
|
|
|
|
// Emit PointCount.
|
|
OS.AddComment("safe point count");
|
|
AP.EmitInt16(MD.size());
|
|
|
|
// And each safe point...
|
|
for (GCFunctionInfo::iterator PI = MD.begin(), PE = MD.end(); PI != PE;
|
|
++PI) {
|
|
// Emit the address of the safe point.
|
|
OS.AddComment("safe point address");
|
|
MCSymbol *Label = PI->Label;
|
|
AP.EmitLabelPlusOffset(Label /*Hi*/, 0 /*Offset*/, 4 /*Size*/);
|
|
}
|
|
|
|
// Stack information never change in safe points! Only print info from the
|
|
// first call-site.
|
|
GCFunctionInfo::iterator PI = MD.begin();
|
|
|
|
// Emit the stack frame size.
|
|
OS.AddComment("stack frame size (in words)");
|
|
AP.EmitInt16(MD.getFrameSize() / IntPtrSize);
|
|
|
|
// Emit stack arity, i.e. the number of stacked arguments.
|
|
unsigned RegisteredArgs = IntPtrSize == 4 ? 5 : 6;
|
|
unsigned StackArity = MD.getFunction().arg_size() > RegisteredArgs
|
|
? MD.getFunction().arg_size() - RegisteredArgs
|
|
: 0;
|
|
OS.AddComment("stack arity");
|
|
AP.EmitInt16(StackArity);
|
|
|
|
// Emit the number of live roots in the function.
|
|
OS.AddComment("live root count");
|
|
AP.EmitInt16(MD.live_size(PI));
|
|
|
|
// And for each live root...
|
|
for (GCFunctionInfo::live_iterator LI = MD.live_begin(PI),
|
|
LE = MD.live_end(PI);
|
|
LI != LE; ++LI) {
|
|
// Emit live root's offset within the stack frame.
|
|
OS.AddComment("stack index (offset / wordsize)");
|
|
AP.EmitInt16(LI->StackOffset / IntPtrSize);
|
|
}
|
|
}
|
|
}
|