Target option DisableJumpTables is a gross hack. Move it to TargetLow…

…ering instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159611 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetLowering.h

@@ -677,6 +677,12 @@ class TargetLowering {
     return UseUnderscoreLongJmp;
   }
 
+  /// supportJumpTables - return whether the target can generate code for
+  /// jump tables.
+  bool supportJumpTables() const {
+    return SupportJumpTables;
+  }
+
   /// getStackPointerRegisterToSaveRestore - If a physical register, this
   /// specifies the register that llvm.savestack/llvm.restorestack should save
   /// and restore.
@@ -991,6 +997,12 @@ class TargetLowering {
     UseUnderscoreLongJmp = Val;
   }
 
+  /// setSupportJumpTables - Indicate whether the target can generate code for
+  /// jump tables.
+  void setSupportJumpTables(bool Val) {
+    SupportJumpTables = Val;
+  }
+
   /// setStackPointerRegisterToSaveRestore - If set to a physical register, this
   /// specifies the register that llvm.savestack/llvm.restorestack should save
   /// and restore.
@@ -1764,6 +1776,10 @@ class TargetLowering {
   /// llvm.longjmp.  Defaults to false.
   bool UseUnderscoreLongJmp;
 
+  /// SupportJumpTables - Whether the target can generate code for jumptables.
+  /// If it's not true, then each jumptable must be lowered into if-then-else's.
+  bool SupportJumpTables;
+
   /// BooleanContents - Information about the contents of the high-bits in
   /// boolean values held in a type wider than i1.  See getBooleanContents.
   BooleanContent BooleanContents;

include/llvm/Target/TargetOptions.h

@@ -48,8 +48,7 @@ namespace llvm {
           UseSoftFloat(false), NoZerosInBSS(false), JITExceptionHandling(false),
           JITEmitDebugInfo(false), JITEmitDebugInfoToDisk(false),
           GuaranteedTailCallOpt(false), DisableTailCalls(false),
-          StackAlignmentOverride(0), RealignStack(true),
-          DisableJumpTables(false), EnableFastISel(false),
+          StackAlignmentOverride(0), RealignStack(true), EnableFastISel(false),
           PositionIndependentExecutable(false), EnableSegmentedStacks(false),
           UseInitArray(false), TrapFuncName(""), FloatABIType(FloatABI::Default),
           AllowFPOpFusion(FPOpFusion::Standard)
@@ -156,10 +155,6 @@ namespace llvm {
     /// automatically realigned, if needed.
     unsigned RealignStack : 1;
 
-    /// DisableJumpTables - This flag indicates jump tables should not be
-    /// generated.
-    unsigned DisableJumpTables : 1;
-
     /// EnableFastISel - This flag enables fast-path instruction selection
     /// which trades away generated code quality in favor of reducing
     /// compile time.

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -2052,7 +2052,7 @@ bool SelectionDAGBuilder::handleSmallSwitchRange(CaseRec& CR,
 }
 
 static inline bool areJTsAllowed(const TargetLowering &TLI) {
-  return !TLI.getTargetMachine().Options.DisableJumpTables &&
+  return TLI.supportJumpTables() &&
           (TLI.isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
            TLI.isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
 }

lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -612,6 +612,7 @@ TargetLowering::TargetLowering(const TargetMachine &tm,
   MinStackArgumentAlignment = 1;
   ShouldFoldAtomicFences = false;
   InsertFencesForAtomic = false;
+  SupportJumpTables = true;
 
   InitLibcallNames(LibcallRoutineNames);
   InitCmpLibcallCCs(CmpLibcallCCs);

lib/Target/PowerPC/PPCISelLowering.cpp

@@ -66,6 +66,7 @@ static TargetLoweringObjectFile *CreateTLOF(const PPCTargetMachine &TM) {
 
 PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   : TargetLowering(TM, CreateTLOF(TM)), PPCSubTarget(*TM.getSubtargetImpl()) {
+  const PPCSubtarget *Subtarget = &TM.getSubtarget<PPCSubtarget>();
 
   setPow2DivIsCheap();
 
@@ -75,7 +76,8 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
 
   // On PPC32/64, arguments smaller than 4/8 bytes are extended, so all
   // arguments are at least 4/8 bytes aligned.
-  setMinStackArgumentAlignment(TM.getSubtarget<PPCSubtarget>().isPPC64() ? 8:4);
+  bool isPPC64 = Subtarget->isPPC64();
+  setMinStackArgumentAlignment(isPPC64 ? 8:4);
 
   // Set up the register classes.
   addRegisterClass(MVT::i32, &PPC::GPRCRegClass);
@@ -142,7 +144,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   setOperationAction(ISD::FLT_ROUNDS_, MVT::i32, Custom);
 
   // If we're enabling GP optimizations, use hardware square root
-  if (!TM.getSubtarget<PPCSubtarget>().hasFSQRT()) {
+  if (!Subtarget->hasFSQRT()) {
     setOperationAction(ISD::FSQRT, MVT::f64, Expand);
     setOperationAction(ISD::FSQRT, MVT::f32, Expand);
   }
@@ -228,8 +230,8 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   // VASTART needs to be custom lowered to use the VarArgsFrameIndex
   setOperationAction(ISD::VASTART           , MVT::Other, Custom);
 
-  if (TM.getSubtarget<PPCSubtarget>().isSVR4ABI()) {
-    if (TM.getSubtarget<PPCSubtarget>().isPPC64()) {
+  if (Subtarget->isSVR4ABI()) {
+    if (isPPC64) {
       // VAARG always uses double-word chunks, so promote anything smaller.
       setOperationAction(ISD::VAARG, MVT::i1, Promote);
       AddPromotedToType (ISD::VAARG, MVT::i1, MVT::i64);
@@ -273,7 +275,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   setCondCodeAction(ISD::SETONE, MVT::f32, Expand);
   setCondCodeAction(ISD::SETONE, MVT::f64, Expand);
 
-  if (TM.getSubtarget<PPCSubtarget>().has64BitSupport()) {
+  if (Subtarget->has64BitSupport()) {
     // They also have instructions for converting between i64 and fp.
     setOperationAction(ISD::FP_TO_SINT, MVT::i64, Custom);
     setOperationAction(ISD::FP_TO_UINT, MVT::i64, Expand);
@@ -292,7 +294,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
     setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
   }
 
-  if (TM.getSubtarget<PPCSubtarget>().use64BitRegs()) {
+  if (Subtarget->use64BitRegs()) {
     // 64-bit PowerPC implementations can support i64 types directly
     addRegisterClass(MVT::i64, &PPC::G8RCRegClass);
     // BUILD_PAIR can't be handled natively, and should be expanded to shl/or
@@ -308,7 +310,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
     setOperationAction(ISD::SRL_PARTS, MVT::i32, Custom);
   }
 
-  if (TM.getSubtarget<PPCSubtarget>().hasAltivec()) {
+  if (Subtarget->hasAltivec()) {
     // First set operation action for all vector types to expand. Then we
     // will selectively turn on ones that can be effectively codegen'd.
     for (unsigned i = (unsigned)MVT::FIRST_VECTOR_VALUETYPE;
@@ -392,7 +394,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
     setOperationAction(ISD::BUILD_VECTOR, MVT::v4f32, Custom);
   }
 
-  if (TM.getSubtarget<PPCSubtarget>().has64BitSupport())
+  if (Subtarget->has64BitSupport())
     setOperationAction(ISD::PREFETCH, MVT::Other, Legal);
 
   setOperationAction(ISD::ATOMIC_LOAD,  MVT::i32, Expand);
@@ -401,7 +403,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   setBooleanContents(ZeroOrOneBooleanContent);
   setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?
 
-  if (TM.getSubtarget<PPCSubtarget>().isPPC64()) {
+  if (isPPC64) {
     setStackPointerRegisterToSaveRestore(PPC::X1);
     setExceptionPointerRegister(PPC::X3);
     setExceptionSelectorRegister(PPC::X4);
@@ -418,7 +420,7 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   setTargetDAGCombine(ISD::BSWAP);
 
   // Darwin long double math library functions have $LDBL128 appended.
-  if (TM.getSubtarget<PPCSubtarget>().isDarwin()) {
+  if (Subtarget->isDarwin()) {
     setLibcallName(RTLIB::COS_PPCF128, "cosl$LDBL128");
     setLibcallName(RTLIB::POW_PPCF128, "powl$LDBL128");
     setLibcallName(RTLIB::REM_PPCF128, "fmodl$LDBL128");
@@ -435,6 +437,11 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   if (PPCSubTarget.isDarwin())
     setPrefFunctionAlignment(4);
 
+  if (isPPC64 && Subtarget->isJITCodeModel())
+    // Temporary workaround for the inability of PPC64 JIT to handle jump
+    // tables.
+    setSupportJumpTables(false);
+
   setInsertFencesForAtomic(true);
 
   setSchedulingPreference(Sched::Hybrid);

lib/Target/PowerPC/PPCTargetMachine.cpp

@@ -117,12 +117,6 @@ bool PPCPassConfig::addPreEmitPass() {
 
 bool PPCTargetMachine::addCodeEmitter(PassManagerBase &PM,
                                       JITCodeEmitter &JCE) {
-  // FIXME: This should be moved to TargetJITInfo!!
-  if (Subtarget.isPPC64())
-    // Temporary workaround for the inability of PPC64 JIT to handle jump
-    // tables.
-    Options.DisableJumpTables = true;
-
   // Inform the subtarget that we are in JIT mode.  FIXME: does this break macho
   // writing?
   Subtarget.SetJITMode();

tools/llc/llc.cpp

@@ -233,11 +233,6 @@ EnableRealignStack("realign-stack",
   cl::desc("Realign stack if needed"),
   cl::init(true));
 
-static cl::opt<bool>
-DisableSwitchTables(cl::Hidden, "disable-jump-tables",
-  cl::desc("Do not generate jump tables."),
-  cl::init(false));
-
 static cl::opt<std::string>
 TrapFuncName("trap-func", cl::Hidden,
   cl::desc("Emit a call to trap function rather than a trap instruction"),
@@ -454,7 +449,6 @@ int main(int argc, char **argv) {
   Options.DisableTailCalls = DisableTailCalls;
   Options.StackAlignmentOverride = OverrideStackAlignment;
   Options.RealignStack = EnableRealignStack;
-  Options.DisableJumpTables = DisableSwitchTables;
   Options.TrapFuncName = TrapFuncName;
   Options.PositionIndependentExecutable = EnablePIE;
   Options.EnableSegmentedStacks = SegmentedStacks;