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Added initial support for small sections on Mips.

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Added gp_rel relocations to support addressing small section contents.
Added command line to specify small section threshold in bytes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53869 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bruno Cardoso Lopes
2008-07-21 18:52:34 +00:00
parent 6116a73da4
commit 91fd532eb9
7 changed files with 86 additions and 28 deletions
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74
lib/Target/Mips/MipsISelLowering.cpp
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@@ -20,6 +20,7 @@
#include "MipsSubtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Intrinsics.h"
#include "llvm/CallingConv.h"
#include "llvm/CodeGen/CallingConvLower.h"
@@ -43,6 +44,7 @@ getTargetNodeName(unsigned Opcode) const
case MipsISD::JmpLink : return "MipsISD::JmpLink";
case MipsISD::Hi : return "MipsISD::Hi";
case MipsISD::Lo : return "MipsISD::Lo";
case MipsISD::GPRel : return "MipsISD::GPRel";
case MipsISD::Ret : return "MipsISD::Ret";
case MipsISD::SelectCC : return "MipsISD::SelectCC";
case MipsISD::FPBrcond : return "MipsISD::FPBrcond";
@@ -89,8 +91,6 @@ MipsTargetLowering(MipsTargetMachine &TM): TargetLowering(TM)
setOperationAction(ISD::SELECT_CC, MVT::f32, Custom);
// Operations not directly supported by Mips.
setConvertAction(MVT::f64, MVT::f32, Expand);
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::BR_CC, MVT::Other, Expand);
setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
@@ -234,34 +234,71 @@ AddLiveIn(MachineFunction &MF, unsigned PReg, TargetRegisterClass *RC)
return VReg;
}
// Discover if this global address can be placed into small data/bss section.
// This should happen for globals with size less than small section size
// threshold in no abicall environments. Data in this section must be addressed
// using gp_rel operator.
bool MipsTargetLowering::IsGlobalInSmallSection(GlobalValue *GV)
{
const TargetData *TD = getTargetData();
const Value *V = dyn_cast<Value>(GV);
const GlobalVariable *GVA = dyn_cast<GlobalVariable>(V);
//const PointerType *PTy = GV->getType();
const Type *Ty = GV->getType()->getElementType();
unsigned Size = TD->getABITypeSize(Ty);
// if this is a internal constant string, there is a special
// section for it, but not in small data/bss.
if (GVA->hasInitializer() && GV->hasInternalLinkage()) {
Constant *C = GVA->getInitializer();
const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
if (CVA && CVA->isCString())
return false;
}
if (Size > 0 && (Size <= Subtarget->getSSectionThreshold()))
return true;
return false;
}
//===----------------------------------------------------------------------===//
// Misc Lower Operation implementation
//===----------------------------------------------------------------------===//
SDOperand MipsTargetLowering::
LowerGlobalAddress(SDOperand Op, SelectionDAG &DAG)
{
SDOperand ResNode;
GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
SDOperand GA = DAG.getTargetGlobalAddress(GV, MVT::i32);
bool isPIC = (getTargetMachine().getRelocationModel() == Reloc::PIC_);
SDOperand HiPart;
if (!isPIC) {
if (!Subtarget->hasABICall()) {
if (isa<Function>(GV)) return GA;
const MVT *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);
// 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;
if (IsGlobalInSmallSection(GV)) { // %gp_rel relocation
SDOperand GPRelNode = DAG.getNode(MipsISD::GPRel, VTs, 1, Ops, 1);
SDOperand GOT = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, MVT::i32);
return DAG.getNode(ISD::ADD, MVT::i32, GOT, GPRelNode);
}
// %hi/%lo relocation
SDOperand HiPart = DAG.getNode(MipsISD::Hi, VTs, 1, Ops, 1);
SDOperand Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
return DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
SDOperand Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
ResNode = DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
} else { // Abicall relocations, TODO: make this cleaner.
SDOperand ResNode = DAG.getLoad(MVT::i32, DAG.getEntryNode(), GA, NULL, 0);
// On functions and global targets not internal linked only
// a load from got/GP is necessary for PIC to work.
if (!GV->hasInternalLinkage() || isa<Function>(GV))
return ResNode;
SDOperand Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
return DAG.getNode(ISD::ADD, MVT::i32, ResNode, Lo);
}
return ResNode;
assert(0 && "Dont know how to handle GlobalAddress");
return SDOperand(0,0);
}
SDOperand MipsTargetLowering::
@@ -596,9 +633,8 @@ LowerCCCArguments(SDOperand Op, SelectionDAG &DAG)
unsigned StackReg = MF.getTarget().getRegisterInfo()->getFrameRegister(MF);
// GP holds the GOT address on PIC calls.
if (getTargetMachine().getRelocationModel() == Reloc::PIC_)
AddLiveIn(MF, Mips::GP, Mips::CPURegsRegisterClass);
// GP must be live into PIC and non-PIC call target.
AddLiveIn(MF, Mips::GP, Mips::CPURegsRegisterClass);
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;