llvm-6502/lib/Target/Mips/Mips16HardFloat.cpp
Reed Kotler fba2a769a1 This patch has two main functions:
1) Fix a specific bug when certain conversion functions are called in a program compiled as mips16 with hard float and
the program is linked as c++. There are two libraries that are reversed in the link order with gcc/g++ and clang/clang++ for
mips16 in this case and the proper stubs will then not be called. These stubs are normally handled in the Mips16HardFloat pass
but in this case we don't know at that time that we need to generate the stubs. This must all be handled later in code generation
and we have moved this functionality to MipsAsmPrinter. When linked as C (gcc or clang) the proper stubs are linked in from libc.

2) Set up the infrastructure to handle 90% of what is in the Mips16HardFloat pass in this new area of MipsAsmPrinter. This is a more
logical place to handle this and we have known for some time that we needed to move the code later and not implement it using
inline asm as we do now but it was not clear exactly where to do this and what mechanism should be used. Now it's clear to us
how to do this and this patch contains the infrastructure to move most of this to MipsAsmPrinter but the actual moving will be done
in a follow on patch. The same infrastructure is used to fix this current bug as described in #1. This change was requested by the list
during the original putback of the Mips16HardFloat pass but was not practical for us do at that time.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201426 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-14 19:16:39 +00:00

543 lines
16 KiB
C++

//===---- Mips16HardFloat.cpp for Mips16 Hard Float --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a pass needed for Mips16 Hard Float
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips16-hard-float"
#include "Mips16HardFloat.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <string>
static void inlineAsmOut
(LLVMContext &C, StringRef AsmString, BasicBlock *BB ) {
std::vector<llvm::Type *> AsmArgTypes;
std::vector<llvm::Value*> AsmArgs;
llvm::FunctionType *AsmFTy =
llvm::FunctionType::get(Type::getVoidTy(C),
AsmArgTypes, false);
llvm::InlineAsm *IA =
llvm::InlineAsm::get(AsmFTy, AsmString, "", true,
/* IsAlignStack */ false,
llvm::InlineAsm::AD_ATT);
CallInst::Create(IA, AsmArgs, "", BB);
}
namespace {
class InlineAsmHelper {
LLVMContext &C;
BasicBlock *BB;
public:
InlineAsmHelper(LLVMContext &C_, BasicBlock *BB_) :
C(C_), BB(BB_) {
}
void Out(StringRef AsmString) {
inlineAsmOut(C, AsmString, BB);
}
};
}
//
// Return types that matter for hard float are:
// float, double, complex float, and complex double
//
enum FPReturnVariant {
FRet, DRet, CFRet, CDRet, NoFPRet
};
//
// Determine which FP return type this function has
//
static FPReturnVariant whichFPReturnVariant(Type *T) {
switch (T->getTypeID()) {
case Type::FloatTyID:
return FRet;
case Type::DoubleTyID:
return DRet;
case Type::StructTyID:
if (T->getStructNumElements() != 2)
break;
if ((T->getContainedType(0)->isFloatTy()) &&
(T->getContainedType(1)->isFloatTy()))
return CFRet;
if ((T->getContainedType(0)->isDoubleTy()) &&
(T->getContainedType(1)->isDoubleTy()))
return CDRet;
break;
default:
break;
}
return NoFPRet;
}
//
// Parameter type that matter are float, (float, float), (float, double),
// double, (double, double), (double, float)
//
enum FPParamVariant {
FSig, FFSig, FDSig,
DSig, DDSig, DFSig, NoSig
};
// which floating point parameter signature variant we are dealing with
//
typedef Type::TypeID TypeID;
const Type::TypeID FloatTyID = Type::FloatTyID;
const Type::TypeID DoubleTyID = Type::DoubleTyID;
static FPParamVariant whichFPParamVariantNeeded(Function &F) {
switch (F.arg_size()) {
case 0:
return NoSig;
case 1:{
TypeID ArgTypeID = F.getFunctionType()->getParamType(0)->getTypeID();
switch (ArgTypeID) {
case FloatTyID:
return FSig;
case DoubleTyID:
return DSig;
default:
return NoSig;
}
}
default: {
TypeID ArgTypeID0 = F.getFunctionType()->getParamType(0)->getTypeID();
TypeID ArgTypeID1 = F.getFunctionType()->getParamType(1)->getTypeID();
switch(ArgTypeID0) {
case FloatTyID: {
switch (ArgTypeID1) {
case FloatTyID:
return FFSig;
case DoubleTyID:
return FDSig;
default:
return FSig;
}
}
case DoubleTyID: {
switch (ArgTypeID1) {
case FloatTyID:
return DFSig;
case DoubleTyID:
return DDSig;
default:
return DSig;
}
}
default:
return NoSig;
}
}
}
llvm_unreachable("can't get here");
}
// Figure out if we need float point based on the function parameters.
// We need to move variables in and/or out of floating point
// registers because of the ABI
//
static bool needsFPStubFromParams(Function &F) {
if (F.arg_size() >=1) {
Type *ArgType = F.getFunctionType()->getParamType(0);
switch (ArgType->getTypeID()) {
case Type::FloatTyID:
case Type::DoubleTyID:
return true;
default:
break;
}
}
return false;
}
static bool needsFPReturnHelper(Function &F) {
Type* RetType = F.getReturnType();
return whichFPReturnVariant(RetType) != NoFPRet;
}
static bool needsFPReturnHelper(const FunctionType &FT) {
Type* RetType = FT.getReturnType();
return whichFPReturnVariant(RetType) != NoFPRet;
}
static bool needsFPHelperFromSig(Function &F) {
return needsFPStubFromParams(F) || needsFPReturnHelper(F);
}
//
// We swap between FP and Integer registers to allow Mips16 and Mips32 to
// interoperate
//
static void swapFPIntParams
(FPParamVariant PV, Module *M, InlineAsmHelper &IAH,
bool LE, bool ToFP) {
//LLVMContext &Context = M->getContext();
std::string MI = ToFP? "mtc1 ": "mfc1 ";
switch (PV) {
case FSig:
IAH.Out(MI + "$$4,$$f12");
break;
case FFSig:
IAH.Out(MI +"$$4,$$f12");
IAH.Out(MI + "$$5,$$f14");
break;
case FDSig:
IAH.Out(MI + "$$4,$$f12");
if (LE) {
IAH.Out(MI + "$$6,$$f14");
IAH.Out(MI + "$$7,$$f15");
} else {
IAH.Out(MI + "$$7,$$f14");
IAH.Out(MI + "$$6,$$f15");
}
break;
case DSig:
if (LE) {
IAH.Out(MI + "$$4,$$f12");
IAH.Out(MI + "$$5,$$f13");
} else {
IAH.Out(MI + "$$5,$$f12");
IAH.Out(MI + "$$4,$$f13");
}
break;
case DDSig:
if (LE) {
IAH.Out(MI + "$$4,$$f12");
IAH.Out(MI + "$$5,$$f13");
IAH.Out(MI + "$$6,$$f14");
IAH.Out(MI + "$$7,$$f15");
} else {
IAH.Out(MI + "$$5,$$f12");
IAH.Out(MI + "$$4,$$f13");
IAH.Out(MI + "$$7,$$f14");
IAH.Out(MI + "$$6,$$f15");
}
break;
case DFSig:
if (LE) {
IAH.Out(MI + "$$4,$$f12");
IAH.Out(MI + "$$5,$$f13");
} else {
IAH.Out(MI + "$$5,$$f12");
IAH.Out(MI + "$$4,$$f13");
}
IAH.Out(MI + "$$6,$$f14");
break;
case NoSig:
return;
}
}
//
// Make sure that we know we already need a stub for this function.
// Having called needsFPHelperFromSig
//
static void assureFPCallStub(Function &F, Module *M,
const MipsSubtarget &Subtarget) {
// for now we only need them for static relocation
if (Subtarget.getRelocationModel() == Reloc::PIC_)
return;
LLVMContext &Context = M->getContext();
bool LE = Subtarget.isLittle();
std::string Name = F.getName();
std::string SectionName = ".mips16.call.fp." + Name;
std::string StubName = "__call_stub_fp_" + Name;
//
// see if we already have the stub
//
Function *FStub = M->getFunction(StubName);
if (FStub && !FStub->isDeclaration()) return;
FStub = Function::Create(F.getFunctionType(),
Function::InternalLinkage, StubName, M);
FStub->addFnAttr("mips16_fp_stub");
FStub->addFnAttr(llvm::Attribute::Naked);
FStub->addFnAttr(llvm::Attribute::NoInline);
FStub->addFnAttr(llvm::Attribute::NoUnwind);
FStub->addFnAttr("nomips16");
FStub->setSection(SectionName);
BasicBlock *BB = BasicBlock::Create(Context, "entry", FStub);
InlineAsmHelper IAH(Context, BB);
IAH.Out(".set reorder");
FPReturnVariant RV = whichFPReturnVariant(FStub->getReturnType());
FPParamVariant PV = whichFPParamVariantNeeded(F);
swapFPIntParams(PV, M, IAH, LE, true);
if (RV != NoFPRet) {
IAH.Out("move $$18, $$31");
IAH.Out("jal " + Name);
} else {
IAH.Out("lui $$25,%hi(" + Name + ")");
IAH.Out("addiu $$25,$$25,%lo(" + Name + ")" );
}
switch (RV) {
case FRet:
IAH.Out("mfc1 $$2,$$f0");
break;
case DRet:
if (LE) {
IAH.Out("mfc1 $$2,$$f0");
IAH.Out("mfc1 $$3,$$f1");
} else {
IAH.Out("mfc1 $$3,$$f0");
IAH.Out("mfc1 $$2,$$f1");
}
break;
case CFRet:
if (LE) {
IAH.Out("mfc1 $$2,$$f0");
IAH.Out("mfc1 $$3,$$f2");
} else {
IAH.Out("mfc1 $$3,$$f0");
IAH.Out("mfc1 $$3,$$f2");
}
break;
case CDRet:
if (LE) {
IAH.Out("mfc1 $$4,$$f2");
IAH.Out("mfc1 $$5,$$f3");
IAH.Out("mfc1 $$2,$$f0");
IAH.Out("mfc1 $$3,$$f1");
} else {
IAH.Out("mfc1 $$5,$$f2");
IAH.Out("mfc1 $$4,$$f3");
IAH.Out("mfc1 $$3,$$f0");
IAH.Out("mfc1 $$2,$$f1");
}
break;
case NoFPRet:
break;
}
if (RV != NoFPRet)
IAH.Out("jr $$18");
else
IAH.Out("jr $$25");
new UnreachableInst(Context, BB);
}
//
// Functions that are llvm intrinsics and don't need helpers.
//
static const char *IntrinsicInline[] =
{"fabs",
"fabsf",
"llvm.ceil.f32", "llvm.ceil.f64",
"llvm.copysign.f32", "llvm.copysign.f64",
"llvm.cos.f32", "llvm.cos.f64",
"llvm.exp.f32", "llvm.exp.f64",
"llvm.exp2.f32", "llvm.exp2.f64",
"llvm.fabs.f32", "llvm.fabs.f64",
"llvm.floor.f32", "llvm.floor.f64",
"llvm.fma.f32", "llvm.fma.f64",
"llvm.log.f32", "llvm.log.f64",
"llvm.log10.f32", "llvm.log10.f64",
"llvm.nearbyint.f32", "llvm.nearbyint.f64",
"llvm.pow.f32", "llvm.pow.f64",
"llvm.powi.f32", "llvm.powi.f64",
"llvm.rint.f32", "llvm.rint.f64",
"llvm.round.f32", "llvm.round.f64",
"llvm.sin.f32", "llvm.sin.f64",
"llvm.sqrt.f32", "llvm.sqrt.f64",
"llvm.trunc.f32", "llvm.trunc.f64",
};
static bool isIntrinsicInline(Function *F) {
return std::binary_search(
IntrinsicInline, array_endof(IntrinsicInline),
F->getName());
}
//
// Returns of float, double and complex need to be handled with a helper
// function.
//
static bool fixupFPReturnAndCall
(Function &F, Module *M, const MipsSubtarget &Subtarget) {
bool Modified = false;
LLVMContext &C = M->getContext();
Type *MyVoid = Type::getVoidTy(C);
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end();
I != E; ++I) {
Instruction &Inst = *I;
if (const ReturnInst *RI = dyn_cast<ReturnInst>(I)) {
Value *RVal = RI->getReturnValue();
if (!RVal) continue;
//
// If there is a return value and it needs a helper function,
// figure out which one and add a call before the actual
// return to this helper. The purpose of the helper is to move
// floating point values from their soft float return mapping to
// where they would have been mapped to in floating point registers.
//
Type *T = RVal->getType();
FPReturnVariant RV = whichFPReturnVariant(T);
if (RV == NoFPRet) continue;
static const char* Helper[NoFPRet] =
{"__mips16_ret_sf", "__mips16_ret_df", "__mips16_ret_sc",
"__mips16_ret_dc"};
const char *Name = Helper[RV];
AttributeSet A;
Value *Params[] = {RVal};
Modified = true;
//
// These helper functions have a different calling ABI so
// this __Mips16RetHelper indicates that so that later
// during call setup, the proper call lowering to the helper
// functions will take place.
//
A = A.addAttribute(C, AttributeSet::FunctionIndex,
"__Mips16RetHelper");
A = A.addAttribute(C, AttributeSet::FunctionIndex,
Attribute::ReadNone);
A = A.addAttribute(C, AttributeSet::FunctionIndex,
Attribute::NoInline);
Value *F = (M->getOrInsertFunction(Name, A, MyVoid, T, NULL));
CallInst::Create(F, Params, "", &Inst );
} else if (const CallInst *CI = dyn_cast<CallInst>(I)) {
const Value* V = CI->getCalledValue();
const Type* T = 0;
if (V) T = V->getType();
const PointerType *PFT=0;
if (T) PFT = dyn_cast<PointerType>(T);
const FunctionType *FT=0;
if (PFT) FT = dyn_cast<FunctionType>(PFT->getElementType());
Function *F_ = CI->getCalledFunction();
if (FT && needsFPReturnHelper(*FT) &&
!(F_ && isIntrinsicInline(F_))) {
Modified=true;
F.addFnAttr("saveS2");
}
if (F_ && !isIntrinsicInline(F_)) {
// pic mode calls are handled by already defined
// helper functions
if (needsFPReturnHelper(*F_)) {
Modified=true;
F.addFnAttr("saveS2");
}
if (Subtarget.getRelocationModel() != Reloc::PIC_ ) {
if (needsFPHelperFromSig(*F_)) {
assureFPCallStub(*F_, M, Subtarget);
Modified=true;
}
}
}
}
}
return Modified;
}
static void createFPFnStub(Function *F, Module *M, FPParamVariant PV,
const MipsSubtarget &Subtarget ) {
bool PicMode = Subtarget.getRelocationModel() == Reloc::PIC_;
bool LE = Subtarget.isLittle();
LLVMContext &Context = M->getContext();
std::string Name = F->getName();
std::string SectionName = ".mips16.fn." + Name;
std::string StubName = "__fn_stub_" + Name;
std::string LocalName = "$$__fn_local_" + Name;
Function *FStub = Function::Create
(F->getFunctionType(),
Function::InternalLinkage, StubName, M);
FStub->addFnAttr("mips16_fp_stub");
FStub->addFnAttr(llvm::Attribute::Naked);
FStub->addFnAttr(llvm::Attribute::NoUnwind);
FStub->addFnAttr(llvm::Attribute::NoInline);
FStub->addFnAttr("nomips16");
FStub->setSection(SectionName);
BasicBlock *BB = BasicBlock::Create(Context, "entry", FStub);
InlineAsmHelper IAH(Context, BB);
IAH.Out(" .set macro");
if (PicMode) {
IAH.Out(".set noreorder");
IAH.Out(".cpload $$25");
IAH.Out(".set reorder");
IAH.Out(".reloc 0,R_MIPS_NONE," + Name);
IAH.Out("la $$25," + LocalName);
}
else {
IAH.Out(".set reorder");
IAH.Out("la $$25," + Name);
}
swapFPIntParams(PV, M, IAH, LE, false);
IAH.Out("jr $$25");
IAH.Out(LocalName + " = " + Name);
new UnreachableInst(FStub->getContext(), BB);
}
//
// remove the use-soft-float attribute
//
static void removeUseSoftFloat(Function &F) {
AttributeSet A;
DEBUG(errs() << "removing -use-soft-float\n");
A = A.addAttribute(F.getContext(), AttributeSet::FunctionIndex,
"use-soft-float", "false");
F.removeAttributes(AttributeSet::FunctionIndex, A);
if (F.hasFnAttribute("use-soft-float")) {
DEBUG(errs() << "still has -use-soft-float\n");
}
F.addAttributes(AttributeSet::FunctionIndex, A);
}
namespace llvm {
//
// 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, Subtarget);
FPParamVariant V = whichFPParamVariantNeeded(*F);
if (V != NoSig) {
Modified = true;
createFPFnStub(F, &M, V, Subtarget);
}
}
return Modified;
}
char Mips16HardFloat::ID = 0;
}
ModulePass *llvm::createMips16HardFloat(MipsTargetMachine &TM) {
return new Mips16HardFloat(TM);
}