Support jump tables when in PIC relocation model
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29318 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter.cpp
index 6e5dab7..a0f377c 100644
--- a/lib/CodeGen/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter.cpp
@@ -52,7 +52,8 @@
DataSectionStartSuffix(""),
SectionEndDirectiveSuffix(0),
ConstantPoolSection("\t.section .rodata\n"),
- JumpTableSection("\t.section .rodata\n"),
+ JumpTableDataSection("\t.section .rodata\n"),
+ JumpTableTextSection("\t.text\n"),
StaticCtorsSection("\t.section .ctors,\"aw\",@progbits"),
StaticDtorsSection("\t.section .dtors,\"aw\",@progbits"),
FourByteConstantSection(0),
@@ -89,7 +90,7 @@
O << CurrentSection << TextSectionStartSuffix << '\n';
}
-/// SwitchToTextSection - Switch to the specified text section of the executable
+/// SwitchToDataSection - Switch to the specified data section of the executable
/// if we are not already in it!
///
void AsmPrinter::SwitchToDataSection(const char *NewSection,
@@ -209,29 +210,30 @@
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
const TargetData *TD = TM.getTargetData();
+ const char *PtrDataDirective = Data32bitsDirective;
- // FIXME: someday we need to handle PIC jump tables
- assert((TM.getRelocationModel() == Reloc::Static ||
- TM.getRelocationModel() == Reloc::DynamicNoPIC) &&
- "Unhandled relocation model emitting jump table information!");
-
- SwitchToDataSection(JumpTableSection, 0);
+ // Pick the directive to use to print the jump table entries, and switch to
+ // the appropriate section.
+ if (TM.getRelocationModel() == Reloc::PIC_) {
+ SwitchToTextSection(JumpTableTextSection, 0);
+ } else {
+ SwitchToDataSection(JumpTableDataSection, 0);
+ if (TD->getPointerSize() == 8)
+ PtrDataDirective = Data64bitsDirective;
+ }
EmitAlignment(Log2_32(TD->getPointerAlignment()));
- // Pick the directive to use based on the pointer size. FIXME: when we support
- // PIC jumptables, this should always use the 32-bit directive for label
- // differences.
- const char *PtrDataDirective = Data32bitsDirective;
- if (TD->getPointerSize() == 8)
- PtrDataDirective = Data64bitsDirective;
-
for (unsigned i = 0, e = JT.size(); i != e; ++i) {
O << PrivateGlobalPrefix << "JTI" << getFunctionNumber() << '_' << i
<< ":\n";
const std::vector<MachineBasicBlock*> &JTBBs = JT[i].MBBs;
for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
O << PtrDataDirective << ' ';
- printBasicBlockLabel(JTBBs[ii]);
+ printBasicBlockLabel(JTBBs[ii], false, false);
+ if (TM.getRelocationModel() == Reloc::PIC_) {
+ O << '-' << PrivateGlobalPrefix << "JTI" << getFunctionNumber()
+ << '_' << i;
+ }
O << '\n';
}
}
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index e8e7a47..76510f3 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -850,9 +850,15 @@
SDOperand Copy = DAG.getCopyFromReg(getRoot(), JT.Reg, PTy);
SDOperand IDX = DAG.getNode(ISD::MUL, PTy, Copy,
DAG.getConstant(PTyBytes, PTy));
- SDOperand ADD = DAG.getNode(ISD::ADD, PTy, IDX, DAG.getJumpTable(JT.JTI,PTy));
+ SDOperand TAB = DAG.getJumpTable(JT.JTI,PTy);
+ SDOperand ADD = DAG.getNode(ISD::ADD, PTy, IDX, TAB);
SDOperand LD = DAG.getLoad(PTy, Copy.getValue(1), ADD, DAG.getSrcValue(0));
- DAG.setRoot(DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), LD));
+ if (TLI.getTargetMachine().getRelocationModel() == Reloc::PIC_) {
+ ADD = DAG.getNode(ISD::ADD, PTy, LD.getValue(0), TAB);
+ DAG.setRoot(DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), ADD));
+ } else {
+ DAG.setRoot(DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), LD));
+ }
}
void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
@@ -896,20 +902,20 @@
// to represent the switch.
MachineFunction *CurMF = CurMBB->getParent();
const BasicBlock *LLVMBB = CurMBB->getBasicBlock();
- Reloc::Model Relocs = TLI.getTargetMachine().getRelocationModel();
// If the switch has more than 5 blocks, and at least 31.25% dense, and the
// target supports indirect branches, then emit a jump table rather than
// lowering the switch to a binary tree of conditional branches.
// FIXME: Make this work with PIC code
if (TLI.isOperationLegal(ISD::BRIND, TLI.getPointerTy()) &&
- (Relocs == Reloc::Static || Relocs == Reloc::DynamicNoPIC) &&
Cases.size() > 5) {
uint64_t First = cast<ConstantIntegral>(Cases.front().first)->getRawValue();
uint64_t Last = cast<ConstantIntegral>(Cases.back().first)->getRawValue();
double Density = (double)Cases.size() / (double)((Last - First) + 1ULL);
if (Density >= 0.3125) {
+ Reloc::Model Relocs = TLI.getTargetMachine().getRelocationModel();
+
// Create a new basic block to hold the code for loading the address
// of the jump table, and jumping to it. Update successor information;
// we will either branch to the default case for the switch, or the jump