6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-25 13:24:46 +00:00
Code Issues Projects Releases Wiki Activity

Revert r237590, "ARM: allow jump tables to be placed as constant islands."

Browse Source 
Caused a miscompile of the Android port of Chromium, details
forthcoming.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237972 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Peter Collingbourne
2015-05-21 23:20:55 +00:00
parent 41cf9ae1b8
commit 66811d9817
11 changed files with 173 additions and 365 deletions
Download Patch File Download Diff File Expand all files Collapse all files

144
lib/Target/ARM/ARMAsmPrinter.cpp
View File

@@ -922,13 +922,16 @@ EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
OutStreamer->EmitValue(Expr, Size);
}
void ARMAsmPrinter::EmitJumpTableAddrs(const MachineInstr *MI) {
const MachineOperand &MO1 = MI->getOperand(1);
unsigned JTI = MO1.getIndex();
void ARMAsmPrinter::EmitJumpTable(const MachineInstr *MI) {
unsigned Opcode = MI->getOpcode();
int OpNum = 1;
if (Opcode == ARM::BR_JTadd)
OpNum = 2;
else if (Opcode == ARM::BR_JTm)
OpNum = 3;
// Make sure the Thumb jump table is 4-byte aligned. This will be a nop for
// ARM mode tables.
EmitAlignment(2);
const MachineOperand &MO1 = MI->getOperand(OpNum);
unsigned JTI = MO1.getIndex();
// Emit a label for the jump table.
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
@@ -969,8 +972,10 @@ void ARMAsmPrinter::EmitJumpTableAddrs(const MachineInstr *MI) {
OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
}
void ARMAsmPrinter::EmitJumpTableInsts(const MachineInstr *MI) {
const MachineOperand &MO1 = MI->getOperand(1);
void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
unsigned Opcode = MI->getOpcode();
int OpNum = (Opcode == ARM::t2BR_JT) ? 2 : 1;
const MachineOperand &MO1 = MI->getOperand(OpNum);
unsigned JTI = MO1.getIndex();
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
@@ -980,56 +985,42 @@ void ARMAsmPrinter::EmitJumpTableInsts(const MachineInstr *MI) {
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
unsigned OffsetWidth = 4;
if (MI->getOpcode() == ARM::t2TBB_JT) {
OffsetWidth = 1;
// Mark the jump table as data-in-code.
OutStreamer->EmitDataRegion(MCDR_DataRegionJT8);
} else if (MI->getOpcode() == ARM::t2TBH_JT) {
OffsetWidth = 2;
// Mark the jump table as data-in-code.
OutStreamer->EmitDataRegion(MCDR_DataRegionJT16);
}
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.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2B)
if (OffsetWidth == 4) {
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2B)
.addExpr(MBBSymbolExpr)
.addImm(ARMCC::AL)
.addReg(0));
}
}
void ARMAsmPrinter::EmitJumpTableTBInst(const MachineInstr *MI,
unsigned OffsetWidth) {
assert((OffsetWidth == 1 || OffsetWidth == 2) && "invalid tbb/tbh width");
const MachineOperand &MO1 = MI->getOperand(1);
unsigned JTI = MO1.getIndex();
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
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;
// Mark the jump table as data-in-code.
OutStreamer->EmitDataRegion(OffsetWidth == 1 ? MCDR_DataRegionJT8
: MCDR_DataRegionJT16);
for (auto MBB : JTBBs) {
const MCExpr *MBBSymbolExpr = MCSymbolRefExpr::Create(MBB->getSymbol(),
OutContext);
continue;
}
// Otherwise it's an offset from the dispatch instruction. Construct an
// MCExpr for the entry. We want a value of the form:
// (BasicBlockAddr - TBBInstAddr + 4) / 2
// (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 - (LCPI0_0 + 4)) / 2
// .byte (LBB1 - (LCPI0_0 + 4)) / 2
// where LCPI0_0 is a label defined just before the TBB instruction using
// this table.
MCSymbol *TBInstPC = GetCPISymbol(MI->getOperand(0).getImm());
const MCExpr *Expr = MCBinaryExpr::CreateAdd(
MCSymbolRefExpr::Create(TBInstPC, OutContext),
MCConstantExpr::Create(4, OutContext), OutContext);
Expr = MCBinaryExpr::CreateSub(MBBSymbolExpr, Expr, OutContext);
// .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);
@@ -1037,10 +1028,8 @@ void ARMAsmPrinter::EmitJumpTableTBInst(const MachineInstr *MI,
// Mark the end of jump table data-in-code region. 32-bit offsets use
// actual branch instructions here, so we don't mark those as a data-region
// at all.
OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
// Make sure the next instruction is 2-byte aligned.
EmitAlignment(1);
if (OffsetWidth != 4)
OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
}
void ARMAsmPrinter::EmitUnwindingInstruction(const MachineInstr *MI) {
@@ -1512,16 +1501,6 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
EmitGlobalConstant(MCPE.Val.ConstVal);
return;
}
case ARM::JUMPTABLE_ADDRS:
EmitJumpTableAddrs(MI);
return;
case ARM::JUMPTABLE_INSTS:
EmitJumpTableInsts(MI);
return;
case ARM::JUMPTABLE_TBB:
case ARM::JUMPTABLE_TBH:
EmitJumpTableTBInst(MI, MI->getOpcode() == ARM::JUMPTABLE_TBB ? 1 : 2);
return;
case ARM::t2BR_JT: {
// Lower and emit the instruction itself, then the jump table following it.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVr)
@@ -1530,19 +1509,37 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
// Output the data for the jump table itself
EmitJump2Table(MI);
return;
}
case ARM::t2TBB_JT: {
// Lower and emit the instruction itself, then the jump table following it.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2TBB)
.addReg(ARM::PC)
.addReg(MI->getOperand(0).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
// Output the data for the jump table itself
EmitJump2Table(MI);
// Make sure the next instruction is 2-byte aligned.
EmitAlignment(1);
return;
}
case ARM::t2TBB_JT:
case ARM::t2TBH_JT: {
unsigned Opc = MI->getOpcode() == ARM::t2TBB_JT ? ARM::t2TBB : ARM::t2TBH;
// Lower and emit the PC label, then the instruction itself.
OutStreamer->EmitLabel(GetCPISymbol(MI->getOperand(3).getImm()));
EmitToStreamer(*OutStreamer, MCInstBuilder(Opc)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(1).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
// Lower and emit the instruction itself, then the jump table following it.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2TBH)
.addReg(ARM::PC)
.addReg(MI->getOperand(0).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
// Output the data for the jump table itself
EmitJump2Table(MI);
return;
}
case ARM::tBR_JTr:
@@ -1562,6 +1559,13 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
if (Opc == ARM::MOVr)
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
// Make sure the Thumb jump table is 4-byte aligned.
if (Opc == ARM::tMOVr)
EmitAlignment(2);
// Output the data for the jump table itself
EmitJumpTable(MI);
return;
}
case ARM::BR_JTm: {
@@ -1585,6 +1589,9 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
TmpInst.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
// Output the data for the jump table itself
EmitJumpTable(MI);
return;
}
case ARM::BR_JTadd: {
@@ -1599,6 +1606,9 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
.addReg(0)
// Add 's' bit operand (always reg0 for this)
.addReg(0));
// Output the data for the jump table itself
EmitJumpTable(MI);
return;
}
case ARM::SPACE: