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Add MC instruction printer support for TB[BH] style thumb2 jump tables.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114553 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach 2010-09-22 17:15:35 +00:00
parent 1b935a3d2e
commit 205a5fa8e4
1 changed files with 27 additions and 24 deletions

51
lib/Target/ARM/ARMAsmPrinter.cpp

@ -1400,42 +1400,46 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
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;
unsigned OffsetWidth = 4;
if (MI->getOpcode() == ARM::t2TBB)
ByteOffset = true;
OffsetWidth = 1;
else if (MI->getOpcode() == ARM::t2TBH)
HalfWordOffset = true;
OffsetWidth = 2;
for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
MachineBasicBlock *MBB = JTBBs[i];
const MCExpr *MBBSymbolExpr = MCSymbolRefExpr::Create(MBB->getSymbol(),
OutContext);
// If this isn't a TBB or TBH, the entries are direct branch instructions.
if (!ByteOffset && !HalfWordOffset) {
if (OffsetWidth == 4) {
MCInst BrInst;
BrInst.setOpcode(ARM::t2B);
BrInst.addOperand(MCOperand::CreateExpr(MCSymbolRefExpr::Create(
MBB->getSymbol(), OutContext)));
BrInst.addOperand(MCOperand::CreateExpr(MBBSymbolExpr));
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
// MCExpr for the entry. We want a value of the form:
// (BasicBlockAddr - TableBeginAddr) / 2
//
// For example, a TBB table with entries jumping to basic blocks BB0 and BB1
// would look like:
// LJTI_0_0:
// .byte (LBB0 - LJTI_0_0) / 2
// .byte (LBB1 - LJTI_0_0) / 2
const MCExpr *Expr =
MCBinaryExpr::CreateSub(MBBSymbolExpr,
MCSymbolRefExpr::Create(JTISymbol, OutContext),
OutContext);
Expr = MCBinaryExpr::CreateDiv(Expr, MCConstantExpr::Create(2, OutContext),
OutContext);
OutStreamer.EmitValue(Expr, OffsetWidth);
}
// Make sure the instruction that follows TBB is 2-byte aligned.
// FIXME: Constant island pass should insert an "ALIGN" instruction instead.
if (MI->getOpcode() == ARM::t2TBB)
EmitAlignment(1);
}
void ARMAsmPrinter::printInstructionThroughMCStreamer(const MachineInstr *MI) {
@ -1654,7 +1658,6 @@ void ARMAsmPrinter::printInstructionThroughMCStreamer(const MachineInstr *MI) {
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
OutStreamer.EmitInstruction(TmpInst);
EmitJump2Table(MI);
return;
}