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Add start of support for MC instruction printer of ARM jump tables. Filling in

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the rest of it is next up.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114500 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach 2010-09-21 23:28:16 +00:00
parent 8614167572
commit 882ef2b76a
2 changed files with 74 additions and 0 deletions
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72
lib/Target/ARM/ARMAsmPrinter.cpp
View File

@ -91,6 +91,8 @@ namespace {
return "ARM Assembly Printer";
}
void EmitJumpTable(const MachineInstr *MI);
void EmitJump2Table(const MachineInstr *MI);
void printInstructionThroughMCStreamer(const MachineInstr *MI);
@ -1383,6 +1385,59 @@ static MCSymbol *getPICLabel(const char *Prefix, unsigned FunctionNumber,
return Label;
}
void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
unsigned Opcode = MI->getOpcode();
int OpNum = (Opcode == ARM::t2BR_JT) ? 2 : 1;
const MachineOperand &MO1 = MI->getOperand(OpNum);
const MachineOperand &MO2 = MI->getOperand(OpNum+1); // Unique Id
unsigned JTI = MO1.getIndex();
// Emit a label for the jump table.
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel2(JTI, MO2.getImm());
OutStreamer.EmitLabel(JTISymbol);
// Emit each entry of the table.
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
bool ByteOffset = false, HalfWordOffset = false;
if (MI->getOpcode() == ARM::t2TBB)
ByteOffset = true;
else if (MI->getOpcode() == ARM::t2TBH)
HalfWordOffset = true;
for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
MachineBasicBlock *MBB = JTBBs[i];
// If this isn't a TBB or TBH, the entries are direct branch instructions.
if (!ByteOffset && !HalfWordOffset) {
MCInst BrInst;
BrInst.setOpcode(ARM::t2B);
BrInst.addOperand(MCOperand::CreateExpr(MCSymbolRefExpr::Create(
MBB->getSymbol(), OutContext)));
OutStreamer.EmitInstruction(BrInst);
continue;
}
// Otherwise it's an offset from the dispatch instruction. Construct an
// MCExpr for the entry.
assert(0 && "FIXME: TB[BH] jump table!!");
#if 0
if (ByteOffset)
O << MAI->getData8bitsDirective();
else if (HalfWordOffset)
O << MAI->getData16bitsDirective();
if (ByteOffset || HalfWordOffset)
O << '(' << *MBB->getSymbol() << "-" << *JTISymbol << ")/2";
else
O << "\tb.w " << *MBB->getSymbol();
if (i != e-1)
O << '\n';
#endif
}
}
void ARMAsmPrinter::printInstructionThroughMCStreamer(const MachineInstr *MI) {
ARMMCInstLower MCInstLowering(OutContext, *Mang, *this);
switch (MI->getOpcode()) {
@ -1592,6 +1647,23 @@ void ARMAsmPrinter::printInstructionThroughMCStreamer(const MachineInstr *MI) {
return;
}
case ARM::t2TBB:
case ARM::t2TBH:
case ARM::t2BR_JT: {
// Lower and emit the instruction itself, then the jump table following it.
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
OutStreamer.EmitInstruction(TmpInst);
EmitJump2Table(MI);
return;
}
case ARM::tBR_JTr:
case ARM::BR_JTr:
case ARM::BR_JTm:
case ARM::BR_JTadd:
abort();
break;
}
MCInst TmpInst;

2
lib/Target/ARM/AsmPrinter/ARMInstPrinter.h
View File

@ -99,6 +99,8 @@ public:
void printRegisterList(const MCInst *MI, unsigned OpNum, raw_ostream &O);
void printCPInstOperand(const MCInst *MI, unsigned OpNum, raw_ostream &O,
const char *Modifier);
// The jump table instructions have custom handling in ARMAsmPrinter
// to output the jump table. Nothing further is necessary here.
void printJTBlockOperand(const MCInst *MI, unsigned OpNum, raw_ostream &O) {}
void printJT2BlockOperand(const MCInst *MI, unsigned OpNum, raw_ostream &O) {}
void printTBAddrMode(const MCInst *MI, unsigned OpNum, raw_ostream &O);