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Diffstat (limited to 'lib/Target/Mips/Mips16HardFloat.cpp')
-rw-r--r-- | lib/Target/Mips/Mips16HardFloat.cpp | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/lib/Target/Mips/Mips16HardFloat.cpp b/lib/Target/Mips/Mips16HardFloat.cpp new file mode 100644 index 0000000000..4d1e61bb99 --- /dev/null +++ b/lib/Target/Mips/Mips16HardFloat.cpp @@ -0,0 +1,141 @@ +//===---- 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/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include <string> + +// +// 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; +} + +// +// Returns of float, double and complex need to be handled with a helper +// function. The "AndCal" part is coming in a later patch. +// +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); + Value *F = (M->getOrInsertFunction(Name, A, MyVoid, T, NULL)); + CallInst::Create(F, Params, "", &Inst ); + } + } + return Modified; +} + +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. (Coming in a later patch). +// 3) in the case of static relocation, generate helper functions so that +// mips16 functions can call extern functions of unknown type (mips16 or +// mips32). (Coming in a later patch). +// 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); + } + return Modified; +} + +char Mips16HardFloat::ID = 0; + +} + +ModulePass *llvm::createMips16HardFloat(MipsTargetMachine &TM) { + return new Mips16HardFloat(TM); +} + |