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Much improved pic jumptable codegen:

Then:
        call    "L1$pb"
"L1$pb":
        popl    %eax
		...
LBB1_1: # entry
        imull   $4, %ecx, %ecx
        leal    LJTI1_0-"L1$pb"(%eax), %edx
        addl    LJTI1_0-"L1$pb"(%ecx,%eax), %edx
        jmpl    *%edx

        .align  2
        .set L1_0_set_3,LBB1_3-LJTI1_0
        .set L1_0_set_2,LBB1_2-LJTI1_0
        .set L1_0_set_5,LBB1_5-LJTI1_0
        .set L1_0_set_4,LBB1_4-LJTI1_0
LJTI1_0:
        .long    L1_0_set_3
        .long    L1_0_set_2

Now:
        call    "L1$pb"
"L1$pb":
        popl    %eax
		...
LBB1_1: # entry
        addl    LJTI1_0-"L1$pb"(%eax,%ecx,4), %eax
        jmpl    *%eax

		.align  2
		.set L1_0_set_3,LBB1_3-"L1$pb"
		.set L1_0_set_2,LBB1_2-"L1$pb"
		.set L1_0_set_5,LBB1_5-"L1$pb"
		.set L1_0_set_4,LBB1_4-"L1$pb"
LJTI1_0:
        .long    L1_0_set_3
        .long    L1_0_set_2

llvm-svn: 43924
This commit is contained in:
Evan Cheng 2007-11-09 01:32:10 +00:00
parent 781ed42681
commit 7d8deec92f
12 changed files with 87 additions and 27 deletions

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@ -305,11 +305,12 @@ namespace llvm {
bool printColon = false,
bool printComment = true) const;
/// printSetLabel - This method prints a set label for the specified
/// MachineBasicBlock
void printSetLabel(unsigned uid, const MachineBasicBlock *MBB) const;
void printSetLabel(unsigned uid, unsigned uid2,
const MachineBasicBlock *MBB) const;
/// printPICJumpTableSetLabel - This method prints a set label for the
/// specified MachineBasicBlock for a jumptable entry.
virtual void printPICJumpTableSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const;
virtual void printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
const MachineBasicBlock *MBB) const;
/// printDataDirective - This method prints the asm directive for the
/// specified type.

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@ -93,7 +93,7 @@ public:
/// usesGlobalOffsetTable - Return true if this target uses a GOT for PIC
/// codegen.
bool usesGlobalOffsetTable() const { return UsesGlobalOffsetTable; }
/// isSelectExpensive - Return true if the select operation is expensive for
/// this target.
bool isSelectExpensive() const { return SelectIsExpensive; }
@ -543,6 +543,11 @@ public:
return false;
}
/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
/// jumptable.
virtual SDOperand getPICJumpTableRelocBase(SDOperand Table,
SelectionDAG &DAG) const;
//===--------------------------------------------------------------------===//
// TargetLowering Optimization Methods
//

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@ -26,6 +26,7 @@
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/ADT/SmallPtrSet.h"
#include <cerrno>
using namespace llvm;
@ -282,11 +283,11 @@ void AsmPrinter::EmitJumpTableInfo(MachineJumpTableInfo *MJTI,
// For PIC codegen, if possible we want to use the SetDirective to reduce
// the number of relocations the assembler will generate for the jump table.
// Set directives are all printed before the jump table itself.
std::set<MachineBasicBlock*> EmittedSets;
SmallPtrSet<MachineBasicBlock*, 16> EmittedSets;
if (TAI->getSetDirective() && IsPic)
for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
if (EmittedSets.insert(JTBBs[ii]).second)
printSetLabel(i, JTBBs[ii]);
if (EmittedSets.insert(JTBBs[ii]))
printPICJumpTableSetLabel(i, JTBBs[ii]);
// On some targets (e.g. darwin) we want to emit two consequtive labels
// before each jump table. The first label is never referenced, but tells
@ -1256,10 +1257,10 @@ void AsmPrinter::printBasicBlockLabel(const MachineBasicBlock *MBB,
<< MBB->getBasicBlock()->getName();
}
/// printSetLabel - This method prints a set label for the specified
/// MachineBasicBlock
void AsmPrinter::printSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const {
/// printPICJumpTableSetLabel - This method prints a set label for the
/// specified MachineBasicBlock for a jumptable entry.
void AsmPrinter::printPICJumpTableSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const {
if (!TAI->getSetDirective())
return;
@ -1270,8 +1271,8 @@ void AsmPrinter::printSetLabel(unsigned uid,
<< '_' << uid << '\n';
}
void AsmPrinter::printSetLabel(unsigned uid, unsigned uid2,
const MachineBasicBlock *MBB) const {
void AsmPrinter::printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
const MachineBasicBlock *MBB) const {
if (!TAI->getSetDirective())
return;

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@ -1599,21 +1599,17 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
case 8: LD = DAG.getLoad(MVT::i64, Chain, Addr, NULL, 0); break;
}
Addr = LD;
if (TLI.getTargetMachine().getRelocationModel() == Reloc::PIC_) {
// For PIC, the sequence is:
// BRIND(load(Jumptable + index) + RelocBase)
// RelocBase is the JumpTable on PPC and X86, GOT on Alpha
SDOperand Reloc;
if (TLI.usesGlobalOffsetTable())
Reloc = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, PTy);
else
Reloc = Table;
Addr = (PTy != MVT::i32) ? DAG.getNode(ISD::SIGN_EXTEND, PTy, LD) : LD;
Addr = DAG.getNode(ISD::ADD, PTy, Addr, Reloc);
Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), Addr);
} else {
Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), LD);
// RelocBase can be JumpTable, GOT or some sort of global base.
if (PTy != MVT::i32)
Addr = DAG.getNode(ISD::SIGN_EXTEND, PTy, Addr);
Addr = DAG.getNode(ISD::ADD, PTy, Addr,
TLI.getPICJumpTableRelocBase(Table, DAG));
}
Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), Addr);
}
}
break;

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@ -393,6 +393,13 @@ unsigned TargetLowering::getVectorTypeBreakdown(MVT::ValueType VT,
return 1;
}
SDOperand TargetLowering::getPICJumpTableRelocBase(SDOperand Table,
SelectionDAG &DAG) const {
if (usesGlobalOffsetTable())
return DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, getPointerTy());
return Table;
}
//===----------------------------------------------------------------------===//
// Optimization Methods
//===----------------------------------------------------------------------===//

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@ -693,7 +693,7 @@ void ARMAsmPrinter::printJTBlockOperand(const MachineInstr *MI, int OpNo) {
for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
MachineBasicBlock *MBB = JTBBs[i];
if (UseSet && JTSets.insert(MBB).second)
printSetLabel(JTI, MO2.getImmedValue(), MBB);
printPICJumpTableSetLabel(JTI, MO2.getImmedValue(), MBB);
O << JTEntryDirective << ' ';
if (UseSet)

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@ -498,6 +498,17 @@ void X86ATTAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
}
}
void X86ATTAsmPrinter::printPICJumpTableSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const {
if (!TAI->getSetDirective())
return;
O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
<< getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ',';
printBasicBlockLabel(MBB, false, false);
O << '-' << computePICLabel(getFunctionNumber(), TAI, Subtarget) << '\n';
}
void X86ATTAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
std::string label = computePICLabel(getFunctionNumber(), TAI, Subtarget);
O << label << "\n" << label << ":";

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@ -77,6 +77,12 @@ struct VISIBILITY_HIDDEN X86ATTAsmPrinter : public X86SharedAsmPrinter {
void printSSECC(const MachineInstr *MI, unsigned Op);
void printMemReference(const MachineInstr *MI, unsigned Op,
const char *Modifier=NULL);
void printPICJumpTableSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const;
void printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
const MachineBasicBlock *MBB) const {
AsmPrinter::printPICJumpTableSetLabel(uid, uid2, MBB);
}
void printPICLabel(const MachineInstr *MI, unsigned Op);
bool runOnMachineFunction(MachineFunction &F);

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@ -650,6 +650,17 @@ X86TargetLowering::X86TargetLowering(TargetMachine &TM)
}
/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
/// jumptable.
SDOperand X86TargetLowering::getPICJumpTableRelocBase(SDOperand Table,
SelectionDAG &DAG) const {
if (usesGlobalOffsetTable())
return DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, getPointerTy());
if (!Subtarget->isPICStyleRIPRel())
return DAG.getNode(X86ISD::GlobalBaseReg, getPointerTy());
return Table;
}
//===----------------------------------------------------------------------===//
// Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//

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@ -296,6 +296,11 @@ namespace llvm {
public:
explicit X86TargetLowering(TargetMachine &TM);
/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
/// jumptable.
SDOperand getPICJumpTableRelocBase(SDOperand Table,
SelectionDAG &DAG) const;
// Return the number of bytes that a function should pop when it returns (in
// addition to the space used by the return address).
//

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@ -235,6 +235,17 @@ void X86IntelAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
O << "]";
}
void X86IntelAsmPrinter::printPICJumpTableSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const {
if (!TAI->getSetDirective())
return;
O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
<< getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ',';
printBasicBlockLabel(MBB, false, false);
O << '-' << "\"L" << getFunctionNumber() << "$pb\"'\n";
}
void X86IntelAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
O << "\"L" << getFunctionNumber() << "$pb\"\n";
O << "\"L" << getFunctionNumber() << "$pb\":";

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@ -99,6 +99,12 @@ struct VISIBILITY_HIDDEN X86IntelAsmPrinter : public X86SharedAsmPrinter {
void printSSECC(const MachineInstr *MI, unsigned Op);
void printMemReference(const MachineInstr *MI, unsigned Op,
const char *Modifier=NULL);
void printPICJumpTableSetLabel(unsigned uid,
const MachineBasicBlock *MBB) const;
void printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
const MachineBasicBlock *MBB) const {
AsmPrinter::printPICJumpTableSetLabel(uid, uid2, MBB);
}
void printPICLabel(const MachineInstr *MI, unsigned Op);
bool runOnMachineFunction(MachineFunction &F);
bool doInitialization(Module &M);