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https://github.com/c64scene-ar/llvm-6502.git
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1a2265bc01
This creates stubs that help Mips32 functions call Mips16 functions which have floating point parameters that are normally passed in floating point registers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181972 91177308-0d34-0410-b5e6-96231b3b80d8
459 lines
13 KiB
C++
459 lines
13 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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#define DEBUG_TYPE "mips16-hard-float"
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#include "Mips16HardFloat.h"
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#include "llvm/IR/Module.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 <string>
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static void inlineAsmOut
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(LLVMContext &C, StringRef AsmString, BasicBlock *BB ) {
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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),
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AsmArgTypes, false);
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llvm::InlineAsm *IA =
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llvm::InlineAsm::get(AsmFTy, AsmString, "", true,
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/* IsAlignStack */ false,
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llvm::InlineAsm::AD_ATT);
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CallInst::Create(IA, AsmArgs, "", BB);
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}
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namespace {
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class InlineAsmHelper {
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LLVMContext &C;
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BasicBlock *BB;
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public:
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InlineAsmHelper(LLVMContext &C_, BasicBlock *BB_) :
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C(C_), BB(BB_) {
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}
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void Out(StringRef AsmString) {
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inlineAsmOut(C, AsmString, BB);
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}
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};
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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 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 void swapFPIntParams
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(FPParamVariant PV, Module *M, InlineAsmHelper &IAH,
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bool LE, bool ToFP) {
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//LLVMContext &Context = M->getContext();
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std::string MI = ToFP? "mtc1 ": "mfc1 ";
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switch (PV) {
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case FSig:
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IAH.Out(MI + "$$4,$$f12");
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break;
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case FFSig:
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IAH.Out(MI +"$$4,$$f12");
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IAH.Out(MI + "$$5,$$f14");
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break;
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case FDSig:
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IAH.Out(MI + "$$4,$$f12");
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if (LE) {
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IAH.Out(MI + "$$6,$$f14");
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IAH.Out(MI + "$$7,$$f15");
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} else {
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IAH.Out(MI + "$$7,$$f14");
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IAH.Out(MI + "$$6,$$f15");
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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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IAH.Out(MI + "$$4,$$f12");
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IAH.Out(MI + "$$5,$$f13");
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} else {
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IAH.Out(MI + "$$5,$$f12");
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IAH.Out(MI + "$$4,$$f13");
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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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IAH.Out(MI + "$$4,$$f12");
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IAH.Out(MI + "$$5,$$f13");
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IAH.Out(MI + "$$6,$$f14");
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IAH.Out(MI + "$$7,$$f15");
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} else {
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IAH.Out(MI + "$$5,$$f12");
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IAH.Out(MI + "$$4,$$f13");
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IAH.Out(MI + "$$7,$$f14");
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IAH.Out(MI + "$$6,$$f15");
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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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IAH.Out(MI + "$$4,$$f12");
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IAH.Out(MI + "$$5,$$f13");
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} else {
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IAH.Out(MI + "$$5,$$f12");
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IAH.Out(MI + "$$4,$$f13");
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}
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IAH.Out(MI + "$$6,$$f14");
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break;
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case NoSig:
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return;
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}
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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 MipsSubtarget &Subtarget){
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// for now we only need them for static relocation
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if (Subtarget.getRelocationModel() == Reloc::PIC_)
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return;
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LLVMContext &Context = M->getContext();
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bool LE = Subtarget.isLittle();
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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_" + 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::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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InlineAsmHelper IAH(Context, BB);
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FPReturnVariant RV = whichFPReturnVariant(FStub->getReturnType());
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FPParamVariant PV = whichFPParamVariantNeeded(F);
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swapFPIntParams(PV, M, IAH, LE, true);
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if (RV != NoFPRet) {
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IAH.Out("move $$18, $$31");
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IAH.Out("jal " + Name);
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} else {
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IAH.Out("lui $$25,%hi(" + Name + ")");
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IAH.Out("addiu $$25,$$25,%lo(" + Name + ")" );
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}
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switch (RV) {
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case FRet:
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IAH.Out("mfc1 $$2,$$f0");
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break;
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case DRet:
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if (LE) {
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IAH.Out("mfc1 $$2,$$f0");
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IAH.Out("mfc1 $$3,$$f1");
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} else {
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IAH.Out("mfc1 $$3,$$f0");
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IAH.Out("mfc1 $$2,$$f1");
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}
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break;
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case CFRet:
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if (LE) {
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IAH.Out("mfc1 $$2,$$f0");
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IAH.Out("mfc1 $$3,$$f2");
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} else {
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IAH.Out("mfc1 $$3,$$f0");
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IAH.Out("mfc1 $$3,$$f2");
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}
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break;
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case CDRet:
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if (LE) {
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IAH.Out("mfc1 $$4,$$f2");
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IAH.Out("mfc1 $$5,$$f3");
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IAH.Out("mfc1 $$2,$$f0");
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IAH.Out("mfc1 $$3,$$f1");
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} else {
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IAH.Out("mfc1 $$5,$$f2");
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IAH.Out("mfc1 $$4,$$f3");
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IAH.Out("mfc1 $$3,$$f0");
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IAH.Out("mfc1 $$2,$$f1");
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}
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break;
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case NoFPRet:
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break;
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}
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if (RV != NoFPRet)
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IAH.Out("jr $$18");
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else
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IAH.Out("jr $$25");
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new UnreachableInst(Context, BB);
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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
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(Function &F, Module *M, const MipsSubtarget &Subtarget) {
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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 (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
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for (BasicBlock::iterator I = BB->begin(), E = BB->end();
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I != E; ++I) {
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Instruction &Inst = *I;
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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* 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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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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Value *F = (M->getOrInsertFunction(Name, A, MyVoid, T, NULL));
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CallInst::Create(F, Params, "", &Inst );
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} else if (const CallInst *CI = dyn_cast<CallInst>(I)) {
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// pic mode calls are handled by already defined
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// helper functions
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if (Subtarget.getRelocationModel() != Reloc::PIC_ ) {
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Function *F_ = CI->getCalledFunction();
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if (F_ && needsFPHelperFromSig(*F_)) {
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assureFPCallStub(*F_, M, Subtarget);
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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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return Modified;
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}
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static void createFPFnStub(Function *F, Module *M, FPParamVariant PV,
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const MipsSubtarget &Subtarget ) {
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bool PicMode = Subtarget.getRelocationModel() == Reloc::PIC_;
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bool LE = Subtarget.isLittle();
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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::ExternalLinkage, 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("nomips16");
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FStub->setSection(SectionName);
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BasicBlock *BB = BasicBlock::Create(Context, "entry", FStub);
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InlineAsmHelper IAH(Context, BB);
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IAH.Out(" .set macro");
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if (PicMode) {
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IAH.Out(".set noreorder");
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IAH.Out(".cpload $$2");
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IAH.Out(".set reorder");
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IAH.Out(".reloc 0,R_MIPS_NONE," + Name);
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IAH.Out("la $$25," + LocalName);
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}
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else
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IAH.Out("la $$25, " + Name);
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swapFPIntParams(PV, M, IAH, LE, false);
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IAH.Out("jr $$25");
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IAH.Out(LocalName + " = " + Name);
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new UnreachableInst(FStub->getContext(), BB);
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}
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namespace llvm {
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//
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// This pass only makes sense when the underlying chip has floating point but
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// we are compiling as mips16.
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// For all mips16 functions (that are not stubs we have already generated), or
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// declared via attributes as nomips16, we must:
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// 1) fixup all returns of float, double, single and double complex
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// by calling a helper function before the actual return.
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// 2) generate helper functions (stubs) that can be called by mips32 functions
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// that will move parameters passed normally passed in floating point
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// registers the soft float equivalents.
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// 3) in the case of static relocation, generate helper functions so that
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// mips16 functions can call extern functions of unknown type (mips16 or
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// mips32).
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// 4) TBD. For pic, calls to extern functions of unknown type are handled by
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// predefined helper functions in libc but this work is currently done
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// during call lowering but it should be moved here in the future.
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//
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bool Mips16HardFloat::runOnModule(Module &M) {
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DEBUG(errs() << "Run on Module Mips16HardFloat\n");
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bool Modified = false;
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for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
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if (F->isDeclaration() || F->hasFnAttribute("mips16_fp_stub") ||
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F->hasFnAttribute("nomips16")) continue;
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Modified |= fixupFPReturnAndCall(*F, &M, Subtarget);
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FPParamVariant V = whichFPParamVariantNeeded(*F);
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if (V != NoSig) {
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Modified = true;
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createFPFnStub(F, &M, V, Subtarget);
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}
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}
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return Modified;
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}
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char Mips16HardFloat::ID = 0;
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}
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ModulePass *llvm::createMips16HardFloat(MipsTargetMachine &TM) {
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return new Mips16HardFloat(TM);
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}
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