llvm-project/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.cpp
Dan Gohman c3536b263f
[WebAssembly] Define call-indirect-overlong and bulk-memory-opt features (#117087)
This defines some new target features. These are subsets of existing
features that reflect implementation concerns:

- "call-indirect-overlong" - implied by "reference-types"; just the
overlong encoding for the `call_indirect` immediate, and not the actual
reference types.

- "bulk-memory-opt" - implied by "bulk-memory": just `memory.copy` and
`memory.fill`, and not the other instructions in the bulk-memory
proposal.

This is split out from https://github.com/llvm/llvm-project/pull/112035.

---------

Co-authored-by: Heejin Ahn <aheejin@gmail.com>
2024-12-02 17:08:07 -08:00

79 lines
2.6 KiB
C++

//===-- WebAssemblySubtarget.cpp - WebAssembly Subtarget Information ------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file implements the WebAssembly-specific subclass of
/// TargetSubtarget.
///
//===----------------------------------------------------------------------===//
#include "WebAssemblySubtarget.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssemblyInstrInfo.h"
#include "llvm/MC/TargetRegistry.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-subtarget"
#define GET_SUBTARGETINFO_CTOR
#define GET_SUBTARGETINFO_TARGET_DESC
#include "WebAssemblyGenSubtargetInfo.inc"
WebAssemblySubtarget &
WebAssemblySubtarget::initializeSubtargetDependencies(StringRef CPU,
StringRef FS) {
// Determine default and user-specified characteristics
LLVM_DEBUG(llvm::dbgs() << "initializeSubtargetDependencies\n");
if (CPU.empty())
CPU = "generic";
ParseSubtargetFeatures(CPU, /*TuneCPU*/ CPU, FS);
FeatureBitset Bits = getFeatureBits();
// bulk-memory implies bulk-memory-opt
if (HasBulkMemory) {
HasBulkMemoryOpt = true;
Bits.set(WebAssembly::FeatureBulkMemoryOpt);
}
// reference-types implies call-indirect-overlong
if (HasReferenceTypes) {
HasCallIndirectOverlong = true;
Bits.set(WebAssembly::FeatureCallIndirectOverlong);
}
// In case we changed any bits, update `MCSubtargetInfo`'s `FeatureBitset`.
setFeatureBits(Bits);
return *this;
}
WebAssemblySubtarget::WebAssemblySubtarget(const Triple &TT,
const std::string &CPU,
const std::string &FS,
const TargetMachine &TM)
: WebAssemblyGenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS),
TargetTriple(TT), InstrInfo(initializeSubtargetDependencies(CPU, FS)),
TLInfo(TM, *this) {}
bool WebAssemblySubtarget::enableAtomicExpand() const {
// If atomics are disabled, atomic ops are lowered instead of expanded
return hasAtomics();
}
bool WebAssemblySubtarget::enableMachineScheduler() const {
// Disable the MachineScheduler for now. Even with ShouldTrackPressure set and
// enableMachineSchedDefaultSched overridden, it appears to have an overall
// negative effect for the kinds of register optimizations we're doing.
return false;
}
bool WebAssemblySubtarget::useAA() const { return true; }