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merge two identical functions and simplify things that are GOT specific

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75091 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-07-09 02:55:47 +00:00
parent e3ee6f1e1f
commit b133a0aff7
1 changed files with 33 additions and 41 deletions
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44
lib/Target/X86/X86ISelLowering.cpp
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@ -1319,18 +1319,9 @@ X86TargetLowering::NameDecorationForFORMAL_ARGUMENTS(SDValue Op) {
} }
/// CallRequiresGOTInRegister - Check whether the call requires the GOT pointer /// isUsingGOT - Return true if the target uses a GOT for PIC, and if we're in
/// in a register before calling. /// PIC mode.
static bool CallRequiresGOTPtrInReg(const TargetMachine &TM) { static bool isUsingGOT(const TargetMachine &TM) {
const X86Subtarget &Subtarget = TM.getSubtarget<X86Subtarget>();
return TM.getRelocationModel() == Reloc::PIC_ &&
Subtarget.isPICStyleGOT();
}
/// CallRequiresFnAddressInReg - Check whether the call requires the function
/// address to be loaded in a register.
static bool CallRequiresFnAddressInReg(const TargetMachine &TM) {
const X86Subtarget &Subtarget = TM.getSubtarget<X86Subtarget>(); const X86Subtarget &Subtarget = TM.getSubtarget<X86Subtarget>();
return TM.getRelocationModel() == Reloc::PIC_ && return TM.getRelocationModel() == Reloc::PIC_ &&
Subtarget.isPICStyleGOT(); Subtarget.isPICStyleGOT();
@ -1802,25 +1793,27 @@ SDValue X86TargetLowering::LowerCALL(SDValue Op, SelectionDAG &DAG) {
InFlag = Chain.getValue(1); InFlag = Chain.getValue(1);
} }
if (isUsingGOT(getTargetMachine())) {
// ELF / PIC requires GOT in the EBX register before function calls via PLT // ELF / PIC requires GOT in the EBX register before function calls via PLT
// GOT pointer. // GOT pointer.
if (!IsTailCall && CallRequiresGOTPtrInReg(getTargetMachine())) { if (!IsTailCall) {
Chain = DAG.getCopyToReg(Chain, dl, X86::EBX, Chain = DAG.getCopyToReg(Chain, dl, X86::EBX,
DAG.getNode(X86ISD::GlobalBaseReg, DAG.getNode(X86ISD::GlobalBaseReg,
DebugLoc::getUnknownLoc(), DebugLoc::getUnknownLoc(),
getPointerTy()), getPointerTy()),
InFlag); InFlag);
InFlag = Chain.getValue(1); InFlag = Chain.getValue(1);
} } else {
// If we are tail calling and generating PIC/GOT style code load the
// address of the callee into ECX. The value in ecx is used as target of
// the tail jump. This is done to circumvent the ebx/callee-saved problem
// for tail calls on PIC/GOT architectures. Normally we would just put the
// address of GOT into ebx and then call target@PLT. But for tail calls
// ebx would be restored (since ebx is callee saved) before jumping to the
// target@PLT.
// If we are tail calling and generating PIC/GOT style code load the address // Note: The actual moving to ECX is done further down.
// of the callee into ecx. The value in ecx is used as target of the tail
// jump. This is done to circumvent the ebx/callee-saved problem for tail
// calls on PIC/GOT architectures. Normally we would just put the address of
// GOT into ebx and then call target@PLT. But for tail calls ebx would be
// restored (since ebx is callee saved) before jumping to the target@PLT.
if (IsTailCall && CallRequiresFnAddressInReg(getTargetMachine())) {
// Note: The actual moving to ecx is done further down.
GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee); GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee);
if (G && !G->getGlobal()->hasHiddenVisibility() && if (G && !G->getGlobal()->hasHiddenVisibility() &&
!G->getGlobal()->hasProtectedVisibility()) !G->getGlobal()->hasProtectedVisibility())
@ -1828,6 +1821,7 @@ SDValue X86TargetLowering::LowerCALL(SDValue Op, SelectionDAG &DAG) {
else if (isa<ExternalSymbolSDNode>(Callee)) else if (isa<ExternalSymbolSDNode>(Callee))
Callee = LowerExternalSymbol(Callee,DAG); Callee = LowerExternalSymbol(Callee,DAG);
} }
}
if (Is64Bit && isVarArg) { if (Is64Bit && isVarArg) {
// From AMD64 ABI document: // From AMD64 ABI document:
@ -1958,9 +1952,7 @@ SDValue X86TargetLowering::LowerCALL(SDValue Op, SelectionDAG &DAG) {
RegsToPass[i].second.getValueType())); RegsToPass[i].second.getValueType()));
// Add an implicit use GOT pointer in EBX. // Add an implicit use GOT pointer in EBX.
if (!IsTailCall && !Is64Bit && if (!IsTailCall && isUsingGOT(getTargetMachine()))
getTargetMachine().getRelocationModel() == Reloc::PIC_ &&
Subtarget->isPICStyleGOT())
Ops.push_back(DAG.getRegister(X86::EBX, getPointerTy())); Ops.push_back(DAG.getRegister(X86::EBX, getPointerTy()));
// Add an implicit use of AL for x86 vararg functions. // Add an implicit use of AL for x86 vararg functions.
@ -2080,7 +2072,7 @@ bool X86TargetLowering::IsEligibleForTailCallOptimization(CallSDNode *TheCall,
SDValue Callee = TheCall->getCallee(); SDValue Callee = TheCall->getCallee();
// On x86/32Bit PIC/GOT tail calls are supported. // On x86/32Bit PIC/GOT tail calls are supported.
if (getTargetMachine().getRelocationModel() != Reloc::PIC_ || if (getTargetMachine().getRelocationModel() != Reloc::PIC_ ||
!Subtarget->isPICStyleGOT()|| !Subtarget->is64Bit()) !Subtarget->isPICStyleGOT() || !Subtarget->is64Bit())
return true; return true;
// Can only do local tail calls (in same module, hidden or protected) on // Can only do local tail calls (in same module, hidden or protected) on