Added support for PIC code with "explicit relocations" *only*.
Removed all macro code for PIC (goodbye "la").
Support tested with shootout bench.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43697 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 5b4ee26..440d3e3 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -39,13 +39,11 @@
{
switch (Opcode)
{
- case MipsISD::JmpLink : return "MipsISD::JmpLink";
- case MipsISD::Hi : return "MipsISD::Hi";
- case MipsISD::Lo : return "MipsISD::Lo";
- case MipsISD::Ret : return "MipsISD::Ret";
- case MipsISD::Add : return "MipsISD::Add";
- case MipsISD::LoadAddr : return "MipsISD::LoadAddr";
- default : return NULL;
+ case MipsISD::JmpLink : return "MipsISD::JmpLink";
+ case MipsISD::Hi : return "MipsISD::Hi";
+ case MipsISD::Lo : return "MipsISD::Lo";
+ case MipsISD::Ret : return "MipsISD::Ret";
+ default : return NULL;
}
}
@@ -149,21 +147,24 @@
{
SDOperand ResNode;
GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
-
SDOperand GA = DAG.getTargetGlobalAddress(GV, MVT::i32);
+ bool isPIC = (getTargetMachine().getRelocationModel() == Reloc::PIC_);
- // On PIC code global addresses are loaded with "la" instruction
- if (!(getTargetMachine().getRelocationModel() == Reloc::PIC_)) {
- const MVT::ValueType *VTs = DAG.getNodeValueTypes(MVT::i32, MVT::Flag);
+ SDOperand HiPart;
+ if (!isPIC) {
+ const MVT::ValueType *VTs = DAG.getNodeValueTypes(MVT::i32);
SDOperand Ops[] = { GA };
+ HiPart = DAG.getNode(MipsISD::Hi, VTs, 1, Ops, 1);
+ } else // Emit Load from Global Pointer
+ HiPart = DAG.getLoad(MVT::i32, DAG.getEntryNode(), GA, NULL, 0);
- SDOperand Hi = DAG.getNode(MipsISD::Hi, VTs, 2, Ops, 1);
- SDOperand Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
+ // On functions and global targets not internal linked only
+ // a load from got/GP is necessary for PIC to work.
+ if ((isPIC) && ((!GV->hasInternalLinkage()) || (isa<Function>(GV))))
+ return HiPart;
- SDOperand InFlag = Hi.getValue(1);
- ResNode = DAG.getNode(MipsISD::Add, MVT::i32, Lo, Hi, InFlag);
- } else
- ResNode = DAG.getNode(MipsISD::LoadAddr, MVT::i32, GA);
+ SDOperand Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
+ ResNode = DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
return ResNode;
}
@@ -211,7 +212,7 @@
/// LowerCCCCallTo - functions arguments are copied from virtual
/// regs to (physical regs)/(stack frame), CALLSEQ_START and
/// CALLSEQ_END are emitted.
-/// TODO: isVarArg, isTailCall, sret, GOT, linkage types.
+/// TODO: isVarArg, isTailCall, sret.
SDOperand MipsTargetLowering::
LowerCCCCallTo(SDOperand Op, SelectionDAG &DAG, unsigned CC)
{
@@ -244,7 +245,7 @@
SmallVector<SDOperand, 8> MemOpChains;
SDOperand StackPtr;
- unsigned LastStackLoc=0;
+ int LastStackLoc=0;
// Walk the register/memloc assignments, inserting copies/loads.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
@@ -268,8 +269,8 @@
break;
}
- // Arguments that can be passed on register,
- // must be kept at RegsToPass vector
+ // Arguments that can be passed on register must be kept at
+ // RegsToPass vector
if (VA.isRegLoc()) {
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
} else {
@@ -294,14 +295,6 @@
}
}
- // Create a stack location to hold GP when PIC is used
- if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
- LastStackLoc = (!LastStackLoc) ? (16) : (LastStackLoc+4);
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
- MFI->CreateFixedObject(4, LastStackLoc);
- MipsFI->setGPStackOffset(LastStackLoc);
- }
-
// Transform all store nodes into one single node because
// all store nodes are independent of each other.
if (!MemOpChains.empty())
@@ -321,13 +314,13 @@
// If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
// direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
- // node so that legalize doesn't hack it. Otherwise we have an indirect call,
- // if PIC is used, the call must use register GP
- if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+ // node so that legalize doesn't hack it.
+ if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), getPointerTy());
else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee))
Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy());
+
// MipsJmpLink = #chain, #target_address, #opt_in_flags...
// = Chain, Callee, Reg#1, Reg#2, ...
//
@@ -349,6 +342,37 @@
Chain = DAG.getNode(MipsISD::JmpLink, NodeTys, &Ops[0], Ops.size());
InFlag = Chain.getValue(1);
+ // Create a stack location to hold GP when PIC is used. This stack
+ // location is used on function prologue to save GP and also after all
+ // emited CALL's to restore GP.
+ if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
+
+ // Function can have an arbitrary number of calls, so
+ // hold the LastStackLoc with the biggest offset.
+ int FI;
+ MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
+ if (LastStackLoc >= MipsFI->getGPStackOffset()) {
+
+ LastStackLoc = (!LastStackLoc) ? (16) : (LastStackLoc+4);
+ // Create the frame index only once. SPOffset here can be anything
+ // (this will be fixed on processFunctionBeforeFrameFinalized)
+ if (MipsFI->getGPStackOffset() == -1) {
+ FI = MFI->CreateFixedObject(4, 0);
+ MipsFI->setGPFI(FI);
+ }
+ MipsFI->setGPStackOffset(LastStackLoc);
+ }
+
+
+ // Reload GP value.
+ FI = MipsFI->getGPFI();
+ SDOperand FIN = DAG.getFrameIndex(FI,getPointerTy());
+ SDOperand GPLoad = DAG.getLoad(MVT::i32, Chain, FIN, NULL, 0);
+ Chain = GPLoad.getValue(1);
+ Chain = DAG.getCopyToReg(Chain, DAG.getRegister(Mips::GP, MVT::i32),
+ GPLoad, SDOperand(0,0));
+ }
+
// Create the CALLSEQ_END node.
NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
Ops.clear();
@@ -389,10 +413,11 @@
ResultVals.push_back(Chain.getValue(0));
}
- // Merge everything together with a MERGE_VALUES node.
ResultVals.push_back(Chain);
+
+ // Merge everything together with a MERGE_VALUES node.
return DAG.getNode(ISD::MERGE_VALUES, TheCall->getVTList(),
- &ResultVals[0], ResultVals.size()).Val;
+ &ResultVals[0], ResultVals.size()).Val;
}
//===----------------------------------------------------------------------===//