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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/DWARFCFIChecker/DWARFCFIFunctionFrameStreamer.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCStreamer.h"
#include <optional>
using namespace llvm;
void CFIFunctionFrameStreamer::updateReceiver(
const std::optional<MCInst> &NewInst) {
assert(hasUnfinishedDwarfFrameInfo() &&
"should have an unfinished DWARF frame here");
assert(!FrameIndices.empty() &&
"there should be an index available for the current frame");
assert(FrameIndices.size() == LastInstructions.size());
assert(LastInstructions.size() == LastDirectiveIndices.size());
auto Frames = getDwarfFrameInfos();
assert(FrameIndices.back() < Frames.size());
unsigned LastDirectiveIndex = LastDirectiveIndices.back();
unsigned CurrentDirectiveIndex =
Frames[FrameIndices.back()].Instructions.size();
assert(CurrentDirectiveIndex >= LastDirectiveIndex);
const MCDwarfFrameInfo *LastFrame = &Frames[FrameIndices.back()];
ArrayRef<MCCFIInstruction> Directives;
if (LastDirectiveIndex < CurrentDirectiveIndex) {
Directives = ArrayRef<MCCFIInstruction>(LastFrame->Instructions);
Directives =
Directives.drop_front(LastDirectiveIndex)
.drop_back(LastFrame->Instructions.size() - CurrentDirectiveIndex);
}
auto MaybeLastInstruction = LastInstructions.back();
if (MaybeLastInstruction)
// The directives are associated with an instruction.
Receiver->emitInstructionAndDirectives(*MaybeLastInstruction, Directives);
else
// The directives are the prologue directives.
Receiver->startFunctionFrame(false /* TODO: should put isEH here */,
Directives);
// Update the internal state for the top frame.
LastInstructions.back() = NewInst;
LastDirectiveIndices.back() = CurrentDirectiveIndex;
}
void CFIFunctionFrameStreamer::emitInstruction(const MCInst &Inst,
const MCSubtargetInfo &STI) {
if (hasUnfinishedDwarfFrameInfo())
// Send the last instruction with the unsent directives already in the frame
// to the receiver.
updateReceiver(Inst);
}
void CFIFunctionFrameStreamer::emitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
LastInstructions.push_back(std::nullopt);
LastDirectiveIndices.push_back(0);
FrameIndices.push_back(getNumFrameInfos());
MCStreamer::emitCFIStartProcImpl(Frame);
}
void CFIFunctionFrameStreamer::emitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame) {
// Send the last instruction with the final directives of the current frame to
// the receiver.
updateReceiver(std::nullopt);
assert(!FrameIndices.empty() && "There should be at least one frame to pop");
LastDirectiveIndices.pop_back();
LastInstructions.pop_back();
FrameIndices.pop_back();
Receiver->finishFunctionFrame();
MCStreamer::emitCFIEndProcImpl(CurFrame);
}
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