Move the FunctionLoweringInfo class and some related utility functions out
of SelectionDAGBuild.h/cpp into its own files, to help separate
general lowering logic from SelectionDAG-specific lowering logic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89667 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
new file mode 100644
index 0000000..964b71f
--- /dev/null
+++ b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -0,0 +1,278 @@
+//===-- 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 "FunctionLoweringInfo.h"
+#include "llvm/CallingConv.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Module.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/Analysis/DebugInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetIntrinsicInfo.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+using namespace llvm;
+
+/// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
+/// of insertvalue or extractvalue indices that identify a member, return
+/// the linearized index of the start of the member.
+///
+unsigned llvm::ComputeLinearIndex(const TargetLowering &TLI, const Type *Ty,
+ const unsigned *Indices,
+ const unsigned *IndicesEnd,
+ unsigned CurIndex) {
+ // Base case: We're done.
+ if (Indices && Indices == IndicesEnd)
+ return CurIndex;
+
+ // Given a struct type, recursively traverse the elements.
+ if (const StructType *STy = dyn_cast<StructType>(Ty)) {
+ for (StructType::element_iterator EB = STy->element_begin(),
+ EI = EB,
+ EE = STy->element_end();
+ EI != EE; ++EI) {
+ if (Indices && *Indices == unsigned(EI - EB))
+ return ComputeLinearIndex(TLI, *EI, Indices+1, IndicesEnd, CurIndex);
+ CurIndex = ComputeLinearIndex(TLI, *EI, 0, 0, CurIndex);
+ }
+ return CurIndex;
+ }
+ // Given an array type, recursively traverse the elements.
+ else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
+ const Type *EltTy = ATy->getElementType();
+ for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
+ if (Indices && *Indices == i)
+ return ComputeLinearIndex(TLI, EltTy, Indices+1, IndicesEnd, CurIndex);
+ CurIndex = ComputeLinearIndex(TLI, EltTy, 0, 0, CurIndex);
+ }
+ return CurIndex;
+ }
+ // We haven't found the type we're looking for, so keep searching.
+ return CurIndex + 1;
+}
+
+/// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
+/// EVTs that represent all the individual underlying
+/// non-aggregate types that comprise it.
+///
+/// If Offsets is non-null, it points to a vector to be filled in
+/// with the in-memory offsets of each of the individual values.
+///
+void llvm::ComputeValueVTs(const TargetLowering &TLI, const Type *Ty,
+ SmallVectorImpl<EVT> &ValueVTs,
+ SmallVectorImpl<uint64_t> *Offsets,
+ uint64_t StartingOffset) {
+ // Given a struct type, recursively traverse the elements.
+ if (const StructType *STy = dyn_cast<StructType>(Ty)) {
+ const StructLayout *SL = TLI.getTargetData()->getStructLayout(STy);
+ for (StructType::element_iterator EB = STy->element_begin(),
+ EI = EB,
+ EE = STy->element_end();
+ EI != EE; ++EI)
+ ComputeValueVTs(TLI, *EI, ValueVTs, Offsets,
+ StartingOffset + SL->getElementOffset(EI - EB));
+ return;
+ }
+ // Given an array type, recursively traverse the elements.
+ if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
+ const Type *EltTy = ATy->getElementType();
+ uint64_t EltSize = TLI.getTargetData()->getTypeAllocSize(EltTy);
+ for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
+ ComputeValueVTs(TLI, EltTy, ValueVTs, Offsets,
+ StartingOffset + i * EltSize);
+ return;
+ }
+ // Interpret void as zero return values.
+ if (Ty == Type::getVoidTy(Ty->getContext()))
+ return;
+ // Base case: we can get an EVT for this LLVM IR type.
+ ValueVTs.push_back(TLI.getValueType(Ty));
+ if (Offsets)
+ Offsets->push_back(StartingOffset);
+}
+
+/// 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(Instruction *I) {
+ if (isa<PHINode>(I)) return true;
+ BasicBlock *BB = I->getParent();
+ for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI)
+ if (cast<Instruction>(*UI)->getParent() != BB || isa<PHINode>(*UI))
+ 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(Argument *A, bool EnableFastISel) {
+ // With FastISel active, we may be splitting blocks, so force creation
+ // of virtual registers for all non-dead arguments.
+ // Don't force virtual registers for byval arguments though, because
+ // fast-isel can't handle those in all cases.
+ if (EnableFastISel && !A->hasByValAttr())
+ return A->use_empty();
+
+ BasicBlock *Entry = A->getParent()->begin();
+ for (Value::use_iterator UI = A->use_begin(), E = A->use_end(); UI != E; ++UI)
+ if (cast<Instruction>(*UI)->getParent() != Entry || isa<SwitchInst>(*UI))
+ return false; // Use not in entry block.
+ return true;
+}
+
+FunctionLoweringInfo::FunctionLoweringInfo(TargetLowering &tli)
+ : TLI(tli) {
+}
+
+void FunctionLoweringInfo::set(Function &fn, MachineFunction &mf,
+ bool EnableFastISel) {
+ Fn = &fn;
+ MF = &mf;
+ RegInfo = &MF->getRegInfo();
+
+ // Create a vreg for each argument register that is not dead and is used
+ // outside of the entry block for the function.
+ for (Function::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::iterator BB = Fn->begin(), EB = Fn->end();
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
+ if (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.
+ StaticAllocaMap[AI] =
+ MF->getFrameInfo()->CreateStackObject(TySize, Align, false);
+ }
+
+ for (; BB != EB; ++BB)
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
+ if (!I->use_empty() && isUsedOutsideOfDefiningBlock(I))
+ if (!isa<AllocaInst>(I) ||
+ !StaticAllocaMap.count(cast<AllocaInst>(I)))
+ InitializeRegForValue(I);
+
+ // 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(), EB = Fn->end(); 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.
+ PHINode *PN;
+ DebugLoc DL;
+ for (BasicBlock::iterator
+ I = BB->begin(), E = BB->end(); I != E; ++I) {
+
+ PN = dyn_cast<PHINode>(I);
+ if (!PN || PN->use_empty()) continue;
+
+ 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(TargetInstrInfo::PHI), PHIReg + i);
+ PHIReg += NumRegisters;
+ }
+ }
+ }
+}
+
+/// 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() {
+ MBBMap.clear();
+ ValueMap.clear();
+ StaticAllocaMap.clear();
+#ifndef NDEBUG
+ CatchInfoLost.clear();
+ CatchInfoFound.clear();
+#endif
+ LiveOutRegInfo.clear();
+}
+
+unsigned FunctionLoweringInfo::MakeReg(EVT VT) {
+ return RegInfo->createVirtualRegister(TLI.getRegClassFor(VT));
+}
+
+/// CreateRegForValue - 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::CreateRegForValue(const Value *V) {
+ SmallVector<EVT, 4> ValueVTs;
+ ComputeValueVTs(TLI, V->getType(), ValueVTs);
+
+ unsigned FirstReg = 0;
+ for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
+ EVT ValueVT = ValueVTs[Value];
+ EVT RegisterVT = TLI.getRegisterType(V->getContext(), ValueVT);
+
+ unsigned NumRegs = TLI.getNumRegisters(V->getContext(), ValueVT);
+ for (unsigned i = 0; i != NumRegs; ++i) {
+ unsigned R = MakeReg(RegisterVT);
+ if (!FirstReg) FirstReg = R;
+ }
+ }
+ return FirstReg;
+}