550 lines
16 KiB
C++
550 lines
16 KiB
C++
//===---- Mips16HardFloat.cpp for Mips16 Hard Float --------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines a pass needed for Mips16 Hard Float
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//
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//===----------------------------------------------------------------------===//
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#include "MipsTargetMachine.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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#include <string>
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using namespace llvm;
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#define DEBUG_TYPE "mips16-hard-float"
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namespace {
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class Mips16HardFloat : public ModulePass {
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public:
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static char ID;
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Mips16HardFloat(MipsTargetMachine &TM_) : ModulePass(ID), TM(TM_) {}
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const char *getPassName() const override {
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return "MIPS16 Hard Float Pass";
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}
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bool runOnModule(Module &M) override;
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protected:
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const MipsTargetMachine &TM;
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};
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static void EmitInlineAsm(LLVMContext &C, BasicBlock *BB, StringRef AsmText) {
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std::vector<llvm::Type *> AsmArgTypes;
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std::vector<llvm::Value *> AsmArgs;
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llvm::FunctionType *AsmFTy =
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llvm::FunctionType::get(Type::getVoidTy(C), AsmArgTypes, false);
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llvm::InlineAsm *IA =
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llvm::InlineAsm::get(AsmFTy, AsmText, "", true,
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/* IsAlignStack */ false, llvm::InlineAsm::AD_ATT);
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CallInst::Create(IA, AsmArgs, "", BB);
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}
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char Mips16HardFloat::ID = 0;
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}
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//
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// Return types that matter for hard float are:
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// float, double, complex float, and complex double
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//
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enum FPReturnVariant {
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FRet, DRet, CFRet, CDRet, NoFPRet
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};
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//
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// Determine which FP return type this function has
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//
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static FPReturnVariant whichFPReturnVariant(Type *T) {
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switch (T->getTypeID()) {
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case Type::FloatTyID:
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return FRet;
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case Type::DoubleTyID:
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return DRet;
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case Type::StructTyID:
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if (T->getStructNumElements() != 2)
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break;
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if ((T->getContainedType(0)->isFloatTy()) &&
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(T->getContainedType(1)->isFloatTy()))
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return CFRet;
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if ((T->getContainedType(0)->isDoubleTy()) &&
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(T->getContainedType(1)->isDoubleTy()))
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return CDRet;
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break;
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default:
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break;
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}
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return NoFPRet;
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}
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//
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// Parameter type that matter are float, (float, float), (float, double),
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// double, (double, double), (double, float)
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//
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enum FPParamVariant {
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FSig, FFSig, FDSig,
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DSig, DDSig, DFSig, NoSig
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};
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// which floating point parameter signature variant we are dealing with
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//
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typedef Type::TypeID TypeID;
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const Type::TypeID FloatTyID = Type::FloatTyID;
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const Type::TypeID DoubleTyID = Type::DoubleTyID;
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static FPParamVariant whichFPParamVariantNeeded(Function &F) {
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switch (F.arg_size()) {
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case 0:
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return NoSig;
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case 1:{
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TypeID ArgTypeID = F.getFunctionType()->getParamType(0)->getTypeID();
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switch (ArgTypeID) {
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case FloatTyID:
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return FSig;
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case DoubleTyID:
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return DSig;
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default:
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return NoSig;
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}
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}
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default: {
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TypeID ArgTypeID0 = F.getFunctionType()->getParamType(0)->getTypeID();
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TypeID ArgTypeID1 = F.getFunctionType()->getParamType(1)->getTypeID();
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switch(ArgTypeID0) {
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case FloatTyID: {
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switch (ArgTypeID1) {
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case FloatTyID:
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return FFSig;
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case DoubleTyID:
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return FDSig;
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default:
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return FSig;
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}
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}
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case DoubleTyID: {
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switch (ArgTypeID1) {
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case FloatTyID:
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return DFSig;
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case DoubleTyID:
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return DDSig;
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default:
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return DSig;
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}
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}
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default:
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return NoSig;
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}
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}
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}
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llvm_unreachable("can't get here");
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}
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// Figure out if we need float point based on the function parameters.
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// We need to move variables in and/or out of floating point
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// registers because of the ABI
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//
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static bool needsFPStubFromParams(Function &F) {
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if (F.arg_size() >=1) {
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Type *ArgType = F.getFunctionType()->getParamType(0);
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switch (ArgType->getTypeID()) {
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case Type::FloatTyID:
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case Type::DoubleTyID:
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return true;
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default:
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break;
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}
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}
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return false;
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}
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static bool needsFPReturnHelper(Function &F) {
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Type* RetType = F.getReturnType();
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return whichFPReturnVariant(RetType) != NoFPRet;
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}
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static bool needsFPReturnHelper(FunctionType &FT) {
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Type* RetType = FT.getReturnType();
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return whichFPReturnVariant(RetType) != NoFPRet;
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}
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static bool needsFPHelperFromSig(Function &F) {
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return needsFPStubFromParams(F) || needsFPReturnHelper(F);
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}
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//
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// We swap between FP and Integer registers to allow Mips16 and Mips32 to
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// interoperate
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//
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static std::string swapFPIntParams(FPParamVariant PV, Module *M, bool LE,
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bool ToFP) {
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std::string MI = ToFP ? "mtc1 ": "mfc1 ";
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std::string AsmText;
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switch (PV) {
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case FSig:
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AsmText += MI + "$$4, $$f12\n";
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break;
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case FFSig:
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AsmText += MI + "$$4, $$f12\n";
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AsmText += MI + "$$5, $$f14\n";
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break;
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case FDSig:
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AsmText += MI + "$$4, $$f12\n";
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if (LE) {
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AsmText += MI + "$$6, $$f14\n";
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AsmText += MI + "$$7, $$f15\n";
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} else {
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AsmText += MI + "$$7, $$f14\n";
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AsmText += MI + "$$6, $$f15\n";
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}
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break;
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case DSig:
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if (LE) {
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AsmText += MI + "$$4, $$f12\n";
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AsmText += MI + "$$5, $$f13\n";
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} else {
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AsmText += MI + "$$5, $$f12\n";
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AsmText += MI + "$$4, $$f13\n";
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}
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break;
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case DDSig:
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if (LE) {
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AsmText += MI + "$$4, $$f12\n";
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AsmText += MI + "$$5, $$f13\n";
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AsmText += MI + "$$6, $$f14\n";
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AsmText += MI + "$$7, $$f15\n";
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} else {
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AsmText += MI + "$$5, $$f12\n";
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AsmText += MI + "$$4, $$f13\n";
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AsmText += MI + "$$7, $$f14\n";
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AsmText += MI + "$$6, $$f15\n";
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}
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break;
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case DFSig:
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if (LE) {
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AsmText += MI + "$$4, $$f12\n";
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AsmText += MI + "$$5, $$f13\n";
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} else {
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AsmText += MI + "$$5, $$f12\n";
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AsmText += MI + "$$4, $$f13\n";
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}
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AsmText += MI + "$$6, $$f14\n";
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break;
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case NoSig:
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break;
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}
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return AsmText;
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}
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//
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// Make sure that we know we already need a stub for this function.
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// Having called needsFPHelperFromSig
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//
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static void assureFPCallStub(Function &F, Module *M,
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const MipsTargetMachine &TM) {
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// for now we only need them for static relocation
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if (TM.isPositionIndependent())
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return;
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LLVMContext &Context = M->getContext();
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bool LE = TM.isLittleEndian();
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std::string Name = F.getName();
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std::string SectionName = ".mips16.call.fp." + Name;
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std::string StubName = "__call_stub_fp_" + Name;
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//
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// see if we already have the stub
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//
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Function *FStub = M->getFunction(StubName);
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if (FStub && !FStub->isDeclaration()) return;
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FStub = Function::Create(F.getFunctionType(),
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Function::InternalLinkage, StubName, M);
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FStub->addFnAttr("mips16_fp_stub");
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FStub->addFnAttr(llvm::Attribute::Naked);
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FStub->addFnAttr(llvm::Attribute::NoInline);
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FStub->addFnAttr(llvm::Attribute::NoUnwind);
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FStub->addFnAttr("nomips16");
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FStub->setSection(SectionName);
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BasicBlock *BB = BasicBlock::Create(Context, "entry", FStub);
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FPReturnVariant RV = whichFPReturnVariant(FStub->getReturnType());
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FPParamVariant PV = whichFPParamVariantNeeded(F);
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std::string AsmText;
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AsmText += ".set reorder\n";
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AsmText += swapFPIntParams(PV, M, LE, true);
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if (RV != NoFPRet) {
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AsmText += "move $$18, $$31\n";
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AsmText += "jal " + Name + "\n";
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} else {
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AsmText += "lui $$25, %hi(" + Name + ")\n";
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AsmText += "addiu $$25, $$25, %lo(" + Name + ")\n";
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}
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switch (RV) {
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case FRet:
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AsmText += "mfc1 $$2, $$f0\n";
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break;
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case DRet:
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if (LE) {
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AsmText += "mfc1 $$2, $$f0\n";
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AsmText += "mfc1 $$3, $$f1\n";
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} else {
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AsmText += "mfc1 $$3, $$f0\n";
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AsmText += "mfc1 $$2, $$f1\n";
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}
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break;
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case CFRet:
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if (LE) {
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AsmText += "mfc1 $$2, $$f0\n";
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AsmText += "mfc1 $$3, $$f2\n";
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} else {
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AsmText += "mfc1 $$3, $$f0\n";
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AsmText += "mfc1 $$3, $$f2\n";
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}
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break;
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case CDRet:
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if (LE) {
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AsmText += "mfc1 $$4, $$f2\n";
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AsmText += "mfc1 $$5, $$f3\n";
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AsmText += "mfc1 $$2, $$f0\n";
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AsmText += "mfc1 $$3, $$f1\n";
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} else {
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AsmText += "mfc1 $$5, $$f2\n";
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AsmText += "mfc1 $$4, $$f3\n";
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AsmText += "mfc1 $$3, $$f0\n";
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AsmText += "mfc1 $$2, $$f1\n";
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}
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break;
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case NoFPRet:
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break;
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}
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if (RV != NoFPRet)
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AsmText += "jr $$18\n";
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else
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AsmText += "jr $$25\n";
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EmitInlineAsm(Context, BB, AsmText);
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new UnreachableInst(Context, BB);
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}
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//
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// Functions that are llvm intrinsics and don't need helpers.
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//
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static const char *const IntrinsicInline[] = {
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"fabs", "fabsf",
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"llvm.ceil.f32", "llvm.ceil.f64",
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"llvm.copysign.f32", "llvm.copysign.f64",
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"llvm.cos.f32", "llvm.cos.f64",
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"llvm.exp.f32", "llvm.exp.f64",
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"llvm.exp2.f32", "llvm.exp2.f64",
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"llvm.fabs.f32", "llvm.fabs.f64",
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"llvm.floor.f32", "llvm.floor.f64",
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"llvm.fma.f32", "llvm.fma.f64",
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"llvm.log.f32", "llvm.log.f64",
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"llvm.log10.f32", "llvm.log10.f64",
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"llvm.nearbyint.f32", "llvm.nearbyint.f64",
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"llvm.pow.f32", "llvm.pow.f64",
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"llvm.powi.f32", "llvm.powi.f64",
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"llvm.rint.f32", "llvm.rint.f64",
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"llvm.round.f32", "llvm.round.f64",
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"llvm.sin.f32", "llvm.sin.f64",
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"llvm.sqrt.f32", "llvm.sqrt.f64",
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"llvm.trunc.f32", "llvm.trunc.f64",
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};
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static bool isIntrinsicInline(Function *F) {
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return std::binary_search(std::begin(IntrinsicInline),
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std::end(IntrinsicInline), F->getName());
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}
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//
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// Returns of float, double and complex need to be handled with a helper
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// function.
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//
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static bool fixupFPReturnAndCall(Function &F, Module *M,
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const MipsTargetMachine &TM) {
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bool Modified = false;
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LLVMContext &C = M->getContext();
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Type *MyVoid = Type::getVoidTy(C);
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for (auto &BB: F)
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for (auto &I: BB) {
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if (const ReturnInst *RI = dyn_cast<ReturnInst>(&I)) {
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Value *RVal = RI->getReturnValue();
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if (!RVal) continue;
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//
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// If there is a return value and it needs a helper function,
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// figure out which one and add a call before the actual
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// return to this helper. The purpose of the helper is to move
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// floating point values from their soft float return mapping to
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// where they would have been mapped to in floating point registers.
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//
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Type *T = RVal->getType();
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FPReturnVariant RV = whichFPReturnVariant(T);
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if (RV == NoFPRet) continue;
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static const char *const Helper[NoFPRet] = {
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"__mips16_ret_sf", "__mips16_ret_df", "__mips16_ret_sc",
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"__mips16_ret_dc"
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};
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const char *Name = Helper[RV];
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AttributeSet A;
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Value *Params[] = {RVal};
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Modified = true;
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//
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// These helper functions have a different calling ABI so
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// this __Mips16RetHelper indicates that so that later
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// during call setup, the proper call lowering to the helper
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// functions will take place.
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//
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A = A.addAttribute(C, AttributeSet::FunctionIndex,
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"__Mips16RetHelper");
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A = A.addAttribute(C, AttributeSet::FunctionIndex,
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Attribute::ReadNone);
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A = A.addAttribute(C, AttributeSet::FunctionIndex,
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Attribute::NoInline);
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Value *F = (M->getOrInsertFunction(Name, A, MyVoid, T, nullptr));
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CallInst::Create(F, Params, "", &I);
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} else if (const CallInst *CI = dyn_cast<CallInst>(&I)) {
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FunctionType *FT = CI->getFunctionType();
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Function *F_ = CI->getCalledFunction();
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if (needsFPReturnHelper(*FT) &&
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!(F_ && isIntrinsicInline(F_))) {
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Modified=true;
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F.addFnAttr("saveS2");
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}
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if (F_ && !isIntrinsicInline(F_)) {
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// pic mode calls are handled by already defined
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// helper functions
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if (needsFPReturnHelper(*F_)) {
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Modified=true;
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F.addFnAttr("saveS2");
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}
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if (!TM.isPositionIndependent()) {
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if (needsFPHelperFromSig(*F_)) {
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assureFPCallStub(*F_, M, TM);
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Modified=true;
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}
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}
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}
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}
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}
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return Modified;
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}
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static void createFPFnStub(Function *F, Module *M, FPParamVariant PV,
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const MipsTargetMachine &TM) {
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bool PicMode = TM.isPositionIndependent();
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bool LE = TM.isLittleEndian();
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LLVMContext &Context = M->getContext();
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std::string Name = F->getName();
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std::string SectionName = ".mips16.fn." + Name;
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std::string StubName = "__fn_stub_" + Name;
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std::string LocalName = "$$__fn_local_" + Name;
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Function *FStub = Function::Create
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(F->getFunctionType(),
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Function::InternalLinkage, StubName, M);
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FStub->addFnAttr("mips16_fp_stub");
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FStub->addFnAttr(llvm::Attribute::Naked);
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FStub->addFnAttr(llvm::Attribute::NoUnwind);
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FStub->addFnAttr(llvm::Attribute::NoInline);
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FStub->addFnAttr("nomips16");
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FStub->setSection(SectionName);
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BasicBlock *BB = BasicBlock::Create(Context, "entry", FStub);
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std::string AsmText;
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if (PicMode) {
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AsmText += ".set noreorder\n";
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AsmText += ".cpload $$25\n";
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AsmText += ".set reorder\n";
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AsmText += ".reloc 0, R_MIPS_NONE, " + Name + "\n";
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AsmText += "la $$25, " + LocalName + "\n";
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} else
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AsmText += "la $$25, " + Name + "\n";
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AsmText += swapFPIntParams(PV, M, LE, false);
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AsmText += "jr $$25\n";
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AsmText += LocalName + " = " + Name + "\n";
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EmitInlineAsm(Context, BB, AsmText);
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new UnreachableInst(FStub->getContext(), BB);
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}
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//
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// remove the use-soft-float attribute
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//
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static void removeUseSoftFloat(Function &F) {
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AttributeSet A;
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DEBUG(errs() << "removing -use-soft-float\n");
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A = A.addAttribute(F.getContext(), AttributeSet::FunctionIndex,
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"use-soft-float", "false");
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F.removeAttributes(AttributeSet::FunctionIndex, A);
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if (F.hasFnAttribute("use-soft-float")) {
|
|
DEBUG(errs() << "still has -use-soft-float\n");
|
|
}
|
|
F.addAttributes(AttributeSet::FunctionIndex, A);
|
|
}
|
|
|
|
|
|
//
|
|
// This pass only makes sense when the underlying chip has floating point but
|
|
// we are compiling as mips16.
|
|
// For all mips16 functions (that are not stubs we have already generated), or
|
|
// declared via attributes as nomips16, we must:
|
|
// 1) fixup all returns of float, double, single and double complex
|
|
// by calling a helper function before the actual return.
|
|
// 2) generate helper functions (stubs) that can be called by mips32
|
|
// functions that will move parameters passed normally passed in
|
|
// floating point
|
|
// registers the soft float equivalents.
|
|
// 3) in the case of static relocation, generate helper functions so that
|
|
// mips16 functions can call extern functions of unknown type (mips16 or
|
|
// mips32).
|
|
// 4) TBD. For pic, calls to extern functions of unknown type are handled by
|
|
// predefined helper functions in libc but this work is currently done
|
|
// during call lowering but it should be moved here in the future.
|
|
//
|
|
bool Mips16HardFloat::runOnModule(Module &M) {
|
|
DEBUG(errs() << "Run on Module Mips16HardFloat\n");
|
|
bool Modified = false;
|
|
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
|
|
if (F->hasFnAttribute("nomips16") &&
|
|
F->hasFnAttribute("use-soft-float")) {
|
|
removeUseSoftFloat(*F);
|
|
continue;
|
|
}
|
|
if (F->isDeclaration() || F->hasFnAttribute("mips16_fp_stub") ||
|
|
F->hasFnAttribute("nomips16")) continue;
|
|
Modified |= fixupFPReturnAndCall(*F, &M, TM);
|
|
FPParamVariant V = whichFPParamVariantNeeded(*F);
|
|
if (V != NoSig) {
|
|
Modified = true;
|
|
createFPFnStub(&*F, &M, V, TM);
|
|
}
|
|
}
|
|
return Modified;
|
|
}
|
|
|
|
|
|
ModulePass *llvm::createMips16HardFloatPass(MipsTargetMachine &TM) {
|
|
return new Mips16HardFloat(TM);
|
|
}
|