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+//===-- FunctionLoweringInfo.cpp ------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements routines for translating functions from LLVM IR into
+// Machine IR.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "function-lowering-info"
+#include "llvm/CodeGen/FunctionLoweringInfo.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
+#include "llvm/Analysis/DebugInfo.h"
+#include "llvm/CodeGen/Analysis.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include <algorithm>
+using namespace llvm;
+
+/// isUsedOutsideOfDefiningBlock - Return true if this instruction is used by
+/// PHI nodes or outside of the basic block that defines it, or used by a
+/// switch or atomic instruction, which may expand to multiple basic blocks.
+static bool isUsedOutsideOfDefiningBlock(const Instruction *I) {
+ if (I->use_empty()) return false;
+ if (isa<PHINode>(I)) return true;
+ const BasicBlock *BB = I->getParent();
+ for (Value::const_use_iterator UI = I->use_begin(), E = I->use_end();
+ UI != E; ++UI) {
+ const User *U = *UI;
+ if (cast<Instruction>(U)->getParent() != BB || isa<PHINode>(U))
+ return true;
+ }
+ return false;
+}
+
+/// isOnlyUsedInEntryBlock - If the specified argument is only used in the
+/// entry block, return true. This includes arguments used by switches, since
+/// the switch may expand into multiple basic blocks.
+static bool isOnlyUsedInEntryBlock(const Argument *A, bool EnableFastISel) {
+ // With FastISel active, we may be splitting blocks, so force creation
+ // of virtual registers for all non-dead arguments.
+ if (EnableFastISel)
+ return A->use_empty();
+
+ const BasicBlock *Entry = A->getParent()->begin();
+ for (Value::const_use_iterator UI = A->use_begin(), E = A->use_end();
+ UI != E; ++UI) {
+ const User *U = *UI;
+ if (cast<Instruction>(U)->getParent() != Entry || isa<SwitchInst>(U))
+ return false; // Use not in entry block.
+ }
+ return true;
+}
+
+FunctionLoweringInfo::FunctionLoweringInfo(const TargetLowering &tli)
+ : TLI(tli) {
+}
+
+void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) {
+ Fn = &fn;
+ MF = &mf;
+ RegInfo = &MF->getRegInfo();
+
+ // Check whether the function can return without sret-demotion.
+ SmallVector<ISD::OutputArg, 4> Outs;
+ GetReturnInfo(Fn->getReturnType(),
+ Fn->getAttributes().getRetAttributes(), Outs, TLI);
+ CanLowerReturn = TLI.CanLowerReturn(Fn->getCallingConv(), Fn->isVarArg(),
+ Outs, Fn->getContext());
+
+ // Create a vreg for each argument register that is not dead and is used
+ // outside of the entry block for the function.
+ for (Function::const_arg_iterator AI = Fn->arg_begin(), E = Fn->arg_end();
+ AI != E; ++AI)
+ if (!isOnlyUsedInEntryBlock(AI, EnableFastISel))
+ InitializeRegForValue(AI);
+
+ // Initialize the mapping of values to registers. This is only set up for
+ // instruction values that are used outside of the block that defines
+ // them.
+ Function::const_iterator BB = Fn->begin(), EB = Fn->end();
+ for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+ if (const AllocaInst *AI = dyn_cast<AllocaInst>(I))
+ if (const ConstantInt *CUI = dyn_cast<ConstantInt>(AI->getArraySize())) {
+ const Type *Ty = AI->getAllocatedType();
+ uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(Ty);
+ unsigned Align =
+ std::max((unsigned)TLI.getTargetData()->getPrefTypeAlignment(Ty),
+ AI->getAlignment());
+
+ TySize *= CUI->getZExtValue(); // Get total allocated size.
+ if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.
+
+ // The object may need to be placed onto the stack near the stack
+ // protector if one exists. Determine here if this object is a suitable
+ // candidate. I.e., it would trigger the creation of a stack protector.
+ bool MayNeedSP =
+ (AI->isArrayAllocation() ||
+ (TySize > 8 && isa<ArrayType>(Ty) &&
+ cast<ArrayType>(Ty)->getElementType()->isIntegerTy(8)));
+ StaticAllocaMap[AI] =
+ MF->getFrameInfo()->CreateStackObject(TySize, Align, false, MayNeedSP);
+ }
+
+ for (; BB != EB; ++BB)
+ for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+ // Mark values used outside their block as exported, by allocating
+ // a virtual register for them.
+ if (isUsedOutsideOfDefiningBlock(I))
+ if (!isa<AllocaInst>(I) ||
+ !StaticAllocaMap.count(cast<AllocaInst>(I)))
+ InitializeRegForValue(I);
+
+ // Collect llvm.dbg.declare information. This is done now instead of
+ // during the initial isel pass through the IR so that it is done
+ // in a predictable order.
+ if (const DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(I)) {
+ MachineModuleInfo &MMI = MF->getMMI();
+ if (MMI.hasDebugInfo() &&
+ DIVariable(DI->getVariable()).Verify() &&
+ !DI->getDebugLoc().isUnknown()) {
+ // Don't handle byval struct arguments or VLAs, for example.
+ // Non-byval arguments are handled here (they refer to the stack
+ // temporary alloca at this point).
+ const Value *Address = DI->getAddress();
+ if (Address) {
+ if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
+ Address = BCI->getOperand(0);
+ if (const AllocaInst *AI = dyn_cast<AllocaInst>(Address)) {
+ DenseMap<const AllocaInst *, int>::iterator SI =
+ StaticAllocaMap.find(AI);
+ if (SI != StaticAllocaMap.end()) { // Check for VLAs.
+ int FI = SI->second;
+ MMI.setVariableDbgInfo(DI->getVariable(),
+ FI, DI->getDebugLoc());
+ }
+ }
+ }
+ }
+ }
+ }
+
+ // Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This
+ // also creates the initial PHI MachineInstrs, though none of the input
+ // operands are populated.
+ for (BB = Fn->begin(); BB != EB; ++BB) {
+ MachineBasicBlock *MBB = mf.CreateMachineBasicBlock(BB);
+ MBBMap[BB] = MBB;
+ MF->push_back(MBB);
+
+ // Transfer the address-taken flag. This is necessary because there could
+ // be multiple MachineBasicBlocks corresponding to one BasicBlock, and only
+ // the first one should be marked.
+ if (BB->hasAddressTaken())
+ MBB->setHasAddressTaken();
+
+ // Create Machine PHI nodes for LLVM PHI nodes, lowering them as
+ // appropriate.
+ for (BasicBlock::const_iterator I = BB->begin();
+ const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
+ if (PN->use_empty()) continue;
+
+ DebugLoc DL = PN->getDebugLoc();
+ unsigned PHIReg = ValueMap[PN];
+ assert(PHIReg && "PHI node does not have an assigned virtual register!");
+
+ SmallVector<EVT, 4> ValueVTs;
+ ComputeValueVTs(TLI, PN->getType(), ValueVTs);
+ for (unsigned vti = 0, vte = ValueVTs.size(); vti != vte; ++vti) {
+ EVT VT = ValueVTs[vti];
+ unsigned NumRegisters = TLI.getNumRegisters(Fn->getContext(), VT);
+ const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
+ for (unsigned i = 0; i != NumRegisters; ++i)
+ BuildMI(MBB, DL, TII->get(TargetOpcode::PHI), PHIReg + i);
+ PHIReg += NumRegisters;
+ }
+ }
+ }
+
+ // Mark landing pad blocks.
+ for (BB = Fn->begin(); BB != EB; ++BB)
+ if (const InvokeInst *Invoke = dyn_cast<InvokeInst>(BB->getTerminator()))
+ MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
+}
+
+/// clear - Clear out all the function-specific state. This returns this
+/// FunctionLoweringInfo to an empty state, ready to be used for a
+/// different function.
+void FunctionLoweringInfo::clear() {
+ assert(CatchInfoFound.size() == CatchInfoLost.size() &&
+ "Not all catch info was assigned to a landing pad!");
+
+ MBBMap.clear();
+ ValueMap.clear();
+ StaticAllocaMap.clear();
+#ifndef NDEBUG
+ CatchInfoLost.clear();
+ CatchInfoFound.clear();
+#endif
+ LiveOutRegInfo.clear();
+ ArgDbgValues.clear();
+ ByValArgFrameIndexMap.clear();
+ RegFixups.clear();
+}
+
+/// CreateReg - Allocate a single virtual register for the given type.
+unsigned FunctionLoweringInfo::CreateReg(EVT VT) {
+ return RegInfo->createVirtualRegister(TLI.getRegClassFor(VT));
+}
+
+/// CreateRegs - Allocate the appropriate number of virtual registers of
+/// the correctly promoted or expanded types. Assign these registers
+/// consecutive vreg numbers and return the first assigned number.
+///
+/// In the case that the given value has struct or array type, this function
+/// will assign registers for each member or element.
+///
+unsigned FunctionLoweringInfo::CreateRegs(const Type *Ty) {
+ SmallVector<EVT, 4> ValueVTs;
+ ComputeValueVTs(TLI, Ty, ValueVTs);
+
+ unsigned FirstReg = 0;
+ for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
+ EVT ValueVT = ValueVTs[Value];
+ EVT RegisterVT = TLI.getRegisterType(Ty->getContext(), ValueVT);
+
+ unsigned NumRegs = TLI.getNumRegisters(Ty->getContext(), ValueVT);
+ for (unsigned i = 0; i != NumRegs; ++i) {
+ unsigned R = CreateReg(RegisterVT);
+ if (!FirstReg) FirstReg = R;
+ }
+ }
+ return FirstReg;
+}
+
+/// setByValArgumentFrameIndex - Record frame index for the byval
+/// argument. This overrides previous frame index entry for this argument,
+/// if any.
+void FunctionLoweringInfo::setByValArgumentFrameIndex(const Argument *A,
+ int FI) {
+ assert (A->hasByValAttr() && "Argument does not have byval attribute!");
+ ByValArgFrameIndexMap[A] = FI;
+}
+
+/// getByValArgumentFrameIndex - Get frame index for the byval argument.
+/// If the argument does not have any assigned frame index then 0 is
+/// returned.
+int FunctionLoweringInfo::getByValArgumentFrameIndex(const Argument *A) {
+ assert (A->hasByValAttr() && "Argument does not have byval attribute!");
+ DenseMap<const Argument *, int>::iterator I =
+ ByValArgFrameIndexMap.find(A);
+ if (I != ByValArgFrameIndexMap.end())
+ return I->second;
+ DEBUG(dbgs() << "Argument does not have assigned frame index!");
+ return 0;
+}
+
+/// AddCatchInfo - Extract the personality and type infos from an eh.selector
+/// call, and add them to the specified machine basic block.
+void llvm::AddCatchInfo(const CallInst &I, MachineModuleInfo *MMI,
+ MachineBasicBlock *MBB) {
+ // Inform the MachineModuleInfo of the personality for this landing pad.
+ const ConstantExpr *CE = cast<ConstantExpr>(I.getArgOperand(1));
+ assert(CE->getOpcode() == Instruction::BitCast &&
+ isa<Function>(CE->getOperand(0)) &&
+ "Personality should be a function");
+ MMI->addPersonality(MBB, cast<Function>(CE->getOperand(0)));
+
+ // Gather all the type infos for this landing pad and pass them along to
+ // MachineModuleInfo.
+ std::vector<const GlobalVariable *> TyInfo;
+ unsigned N = I.getNumArgOperands();
+
+ for (unsigned i = N - 1; i > 1; --i) {
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(I.getArgOperand(i))) {
+ unsigned FilterLength = CI->getZExtValue();
+ unsigned FirstCatch = i + FilterLength + !FilterLength;
+ assert(FirstCatch <= N && "Invalid filter length");
+
+ if (FirstCatch < N) {
+ TyInfo.reserve(N - FirstCatch);
+ for (unsigned j = FirstCatch; j < N; ++j)
+ TyInfo.push_back(ExtractTypeInfo(I.getArgOperand(j)));
+ MMI->addCatchTypeInfo(MBB, TyInfo);
+ TyInfo.clear();
+ }
+
+ if (!FilterLength) {
+ // Cleanup.
+ MMI->addCleanup(MBB);
+ } else {
+ // Filter.
+ TyInfo.reserve(FilterLength - 1);
+ for (unsigned j = i + 1; j < FirstCatch; ++j)
+ TyInfo.push_back(ExtractTypeInfo(I.getArgOperand(j)));
+ MMI->addFilterTypeInfo(MBB, TyInfo);
+ TyInfo.clear();
+ }
+
+ N = i;
+ }
+ }
+
+ if (N > 2) {
+ TyInfo.reserve(N - 2);
+ for (unsigned j = 2; j < N; ++j)
+ TyInfo.push_back(ExtractTypeInfo(I.getArgOperand(j)));
+ MMI->addCatchTypeInfo(MBB, TyInfo);
+ }
+}
+
+void llvm::CopyCatchInfo(const BasicBlock *SrcBB, const BasicBlock *DestBB,
+ MachineModuleInfo *MMI, FunctionLoweringInfo &FLI) {
+ for (BasicBlock::const_iterator I = SrcBB->begin(), E = --SrcBB->end();
+ I != E; ++I)
+ if (const EHSelectorInst *EHSel = dyn_cast<EHSelectorInst>(I)) {
+ // Apply the catch info to DestBB.
+ AddCatchInfo(*EHSel, MMI, FLI.MBBMap[DestBB]);
+#ifndef NDEBUG
+ if (!FLI.MBBMap[SrcBB]->isLandingPad())
+ FLI.CatchInfoFound.insert(EHSel);
+#endif
+ }
+}
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