//
// 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->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;
}
//
// 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);
}
