99 lines
3.3 KiB
C++
99 lines
3.3 KiB
C++
//===-- WebAssemblyArgumentMove.cpp - Argument instruction moving ---------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
///
|
|
/// \file
|
|
/// This file moves ARGUMENT instructions after ScheduleDAG scheduling.
|
|
///
|
|
/// Arguments are really live-in registers, however, since we use virtual
|
|
/// registers and LLVM doesn't support live-in virtual registers, we're
|
|
/// currently making do with ARGUMENT instructions which are placed at the top
|
|
/// of the entry block. The trick is to get them to *stay* at the top of the
|
|
/// entry block.
|
|
///
|
|
/// The ARGUMENTS physical register keeps these instructions pinned in place
|
|
/// during liveness-aware CodeGen passes, however one thing which does not
|
|
/// respect this is the ScheduleDAG scheduler. This pass is therefore run
|
|
/// immediately after that.
|
|
///
|
|
/// This is all hopefully a temporary solution until we find a better solution
|
|
/// for describing the live-in nature of arguments.
|
|
///
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
|
|
#include "WebAssembly.h"
|
|
#include "WebAssemblyMachineFunctionInfo.h"
|
|
#include "WebAssemblySubtarget.h"
|
|
#include "WebAssemblyUtilities.h"
|
|
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
|
|
#include "llvm/CodeGen/MachineRegisterInfo.h"
|
|
#include "llvm/CodeGen/Passes.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "wasm-argument-move"
|
|
|
|
namespace {
|
|
class WebAssemblyArgumentMove final : public MachineFunctionPass {
|
|
public:
|
|
static char ID; // Pass identification, replacement for typeid
|
|
WebAssemblyArgumentMove() : MachineFunctionPass(ID) {}
|
|
|
|
StringRef getPassName() const override { return "WebAssembly Argument Move"; }
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.setPreservesCFG();
|
|
AU.addPreserved<MachineBlockFrequencyInfo>();
|
|
AU.addPreservedID(MachineDominatorsID);
|
|
MachineFunctionPass::getAnalysisUsage(AU);
|
|
}
|
|
|
|
bool runOnMachineFunction(MachineFunction &MF) override;
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
char WebAssemblyArgumentMove::ID = 0;
|
|
INITIALIZE_PASS(WebAssemblyArgumentMove, DEBUG_TYPE,
|
|
"Move ARGUMENT instructions for WebAssembly", false, false)
|
|
|
|
FunctionPass *llvm::createWebAssemblyArgumentMove() {
|
|
return new WebAssemblyArgumentMove();
|
|
}
|
|
|
|
bool WebAssemblyArgumentMove::runOnMachineFunction(MachineFunction &MF) {
|
|
LLVM_DEBUG({
|
|
dbgs() << "********** Argument Move **********\n"
|
|
<< "********** Function: " << MF.getName() << '\n';
|
|
});
|
|
|
|
bool Changed = false;
|
|
MachineBasicBlock &EntryMBB = MF.front();
|
|
MachineBasicBlock::iterator InsertPt = EntryMBB.end();
|
|
|
|
// Look for the first NonArg instruction.
|
|
for (MachineInstr &MI : EntryMBB) {
|
|
if (!WebAssembly::isArgument(MI)) {
|
|
InsertPt = MI;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Now move any argument instructions later in the block
|
|
// to before our first NonArg instruction.
|
|
for (MachineInstr &MI : llvm::make_range(InsertPt, EntryMBB.end())) {
|
|
if (WebAssembly::isArgument(MI)) {
|
|
EntryMBB.insert(InsertPt, MI.removeFromParent());
|
|
Changed = true;
|
|
}
|
|
}
|
|
|
|
return Changed;
|
|
}
|