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llvm-mirror/lib/Target/Sparc/SparcSubtarget.cpp
Craig Topper 10839866a1 [X86][MC][Target] Initial backend support a tune CPU to support -mtune
This patch implements initial backend support for a -mtune CPU controlled by a "tune-cpu" function attribute. If the attribute is not present X86 will use the resolved CPU from target-cpu attribute or command line.

This patch adds MC layer support a tune CPU. Each CPU now has two sets of features stored in their GenSubtargetInfo.inc tables . These features lists are passed separately to the Processor and ProcessorModel classes in tablegen. The tune list defaults to an empty list to avoid changes to non-X86. This annoyingly increases the size of static tables on all target as we now store 24 more bytes per CPU. I haven't quantified the overall impact, but I can if we're concerned.

One new test is added to X86 to show a few tuning features with mismatched tune-cpu and target-cpu/target-feature attributes to demonstrate independent control. Another new test is added to demonstrate that the scheduler model follows the tune CPU.

I have not added a -mtune to llc/opt or MC layer command line yet. With no attributes we'll just use the -mcpu for both. MC layer tools will always follow the normal CPU for tuning.

Differential Revision: https://reviews.llvm.org/D85165
2020-08-14 15:31:50 -07:00

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//===-- SparcSubtarget.cpp - SPARC 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the SPARC specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
#include "SparcSubtarget.h"
#include "Sparc.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
#define DEBUG_TYPE "sparc-subtarget"
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "SparcGenSubtargetInfo.inc"
void SparcSubtarget::anchor() { }
SparcSubtarget &SparcSubtarget::initializeSubtargetDependencies(StringRef CPU,
StringRef FS) {
UseSoftMulDiv = false;
IsV9 = false;
IsLeon = false;
V8DeprecatedInsts = false;
IsVIS = false;
IsVIS2 = false;
IsVIS3 = false;
HasHardQuad = false;
UsePopc = false;
UseSoftFloat = false;
HasNoFSMULD = false;
HasNoFMULS = false;
// Leon features
HasLeonCasa = false;
HasUmacSmac = false;
HasPWRPSR = false;
InsertNOPLoad = false;
FixAllFDIVSQRT = false;
DetectRoundChange = false;
HasLeonCycleCounter = false;
// Determine default and user specified characteristics
std::string CPUName = std::string(CPU);
if (CPUName.empty())
CPUName = (Is64Bit) ? "v9" : "v8";
// Parse features string.
ParseSubtargetFeatures(CPUName, /*TuneCPU*/ CPUName, FS);
// Popc is a v9-only instruction.
if (!IsV9)
UsePopc = false;
return *this;
}
SparcSubtarget::SparcSubtarget(const Triple &TT, const std::string &CPU,
const std::string &FS, const TargetMachine &TM,
bool is64Bit)
: SparcGenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS), TargetTriple(TT),
Is64Bit(is64Bit), InstrInfo(initializeSubtargetDependencies(CPU, FS)),
TLInfo(TM, *this), FrameLowering(*this) {}
int SparcSubtarget::getAdjustedFrameSize(int frameSize) const {
if (is64Bit()) {
// All 64-bit stack frames must be 16-byte aligned, and must reserve space
// for spilling the 16 window registers at %sp+BIAS..%sp+BIAS+128.
frameSize += 128;
// Frames with calls must also reserve space for 6 outgoing arguments
// whether they are used or not. LowerCall_64 takes care of that.
frameSize = alignTo(frameSize, 16);
} else {
// Emit the correct save instruction based on the number of bytes in
// the frame. Minimum stack frame size according to V8 ABI is:
// 16 words for register window spill
// 1 word for address of returned aggregate-value
// + 6 words for passing parameters on the stack
// ----------
// 23 words * 4 bytes per word = 92 bytes
frameSize += 92;
// Round up to next doubleword boundary -- a double-word boundary
// is required by the ABI.
frameSize = alignTo(frameSize, 8);
}
return frameSize;
}
bool SparcSubtarget::enableMachineScheduler() const {
return true;
}