Much improved pic jumptable codegen:

Then:
        call    "L1$pb"
"L1$pb":
        popl    %eax
		...
LBB1_1: # entry
        imull   $4, %ecx, %ecx
        leal    LJTI1_0-"L1$pb"(%eax), %edx
        addl    LJTI1_0-"L1$pb"(%ecx,%eax), %edx
        jmpl    *%edx

        .align  2
        .set L1_0_set_3,LBB1_3-LJTI1_0
        .set L1_0_set_2,LBB1_2-LJTI1_0
        .set L1_0_set_5,LBB1_5-LJTI1_0
        .set L1_0_set_4,LBB1_4-LJTI1_0
LJTI1_0:
        .long    L1_0_set_3
        .long    L1_0_set_2

Now:
        call    "L1$pb"
"L1$pb":
        popl    %eax
		...
LBB1_1: # entry
        addl    LJTI1_0-"L1$pb"(%eax,%ecx,4), %eax
        jmpl    *%eax

		.align  2
		.set L1_0_set_3,LBB1_3-"L1$pb"
		.set L1_0_set_2,LBB1_2-"L1$pb"
		.set L1_0_set_5,LBB1_5-"L1$pb"
		.set L1_0_set_4,LBB1_4-"L1$pb"
LJTI1_0:
        .long    L1_0_set_3
        .long    L1_0_set_2


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43924 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -305,10 +305,11 @@ namespace llvm {
                                       bool printColon = false,
                                       bool printComment = true) const;
                                       
-    /// printSetLabel - This method prints a set label for the specified
+    /// printPICJumpTableSetLabel - This method prints a set label for the
-    /// MachineBasicBlock
+    /// specified MachineBasicBlock for a jumptable entry.
-    void printSetLabel(unsigned uid, const MachineBasicBlock *MBB) const;
+    virtual void printPICJumpTableSetLabel(unsigned uid,
-    void printSetLabel(unsigned uid, unsigned uid2,
+                                           const MachineBasicBlock *MBB) const;
+    virtual void printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
                                            const MachineBasicBlock *MBB) const;
 
     /// printDataDirective - This method prints the asm directive for the

include/llvm/Target/TargetLowering.h

@@ -543,6 +543,11 @@ public:
     return false;
   }
   
+  /// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
+  /// jumptable.
+  virtual SDOperand getPICJumpTableRelocBase(SDOperand Table,
+                                             SelectionDAG &DAG) const;
+  
   //===--------------------------------------------------------------------===//
   // TargetLowering Optimization Methods
   //

lib/CodeGen/AsmPrinter.cpp

@@ -26,6 +26,7 @@
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include <cerrno>
 using namespace llvm;
 
@@ -282,11 +283,11 @@ void AsmPrinter::EmitJumpTableInfo(MachineJumpTableInfo *MJTI,
     // For PIC codegen, if possible we want to use the SetDirective to reduce
     // the number of relocations the assembler will generate for the jump table.
     // Set directives are all printed before the jump table itself.
-    std::set<MachineBasicBlock*> EmittedSets;
+    SmallPtrSet<MachineBasicBlock*, 16> EmittedSets;
     if (TAI->getSetDirective() && IsPic)
       for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
-        if (EmittedSets.insert(JTBBs[ii]).second)
+        if (EmittedSets.insert(JTBBs[ii]))
-          printSetLabel(i, JTBBs[ii]);
+          printPICJumpTableSetLabel(i, JTBBs[ii]);
     
     // On some targets (e.g. darwin) we want to emit two consequtive labels
     // before each jump table.  The first label is never referenced, but tells
@@ -1256,9 +1257,9 @@ void AsmPrinter::printBasicBlockLabel(const MachineBasicBlock *MBB,
       << MBB->getBasicBlock()->getName();
 }
 
-/// printSetLabel - This method prints a set label for the specified
+/// printPICJumpTableSetLabel - This method prints a set label for the
-/// MachineBasicBlock
+/// specified MachineBasicBlock for a jumptable entry.
-void AsmPrinter::printSetLabel(unsigned uid, 
+void AsmPrinter::printPICJumpTableSetLabel(unsigned uid, 
                                            const MachineBasicBlock *MBB) const {
   if (!TAI->getSetDirective())
     return;
@@ -1270,7 +1271,7 @@ void AsmPrinter::printSetLabel(unsigned uid,
     << '_' << uid << '\n';
 }
 
-void AsmPrinter::printSetLabel(unsigned uid, unsigned uid2,
+void AsmPrinter::printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
                                            const MachineBasicBlock *MBB) const {
   if (!TAI->getSetDirective())
     return;

lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

@@ -1599,21 +1599,17 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
       case 8: LD = DAG.getLoad(MVT::i64, Chain, Addr, NULL, 0); break;
       }
 
+      Addr = LD;
       if (TLI.getTargetMachine().getRelocationModel() == Reloc::PIC_) {
         // For PIC, the sequence is:
         // BRIND(load(Jumptable + index) + RelocBase)
-        // RelocBase is the JumpTable on PPC and X86, GOT on Alpha
+        // RelocBase can be JumpTable, GOT or some sort of global base.
-        SDOperand Reloc;
+        if (PTy != MVT::i32)
-        if (TLI.usesGlobalOffsetTable())
+          Addr = DAG.getNode(ISD::SIGN_EXTEND, PTy, Addr);
-          Reloc = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, PTy);
+        Addr = DAG.getNode(ISD::ADD, PTy, Addr,
-        else
+                           TLI.getPICJumpTableRelocBase(Table, DAG));
-          Reloc = Table;
-        Addr = (PTy != MVT::i32) ? DAG.getNode(ISD::SIGN_EXTEND, PTy, LD) : LD;
-        Addr = DAG.getNode(ISD::ADD, PTy, Addr, Reloc);
-        Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), Addr);
-      } else {
-        Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), LD);
       }
+      Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), Addr);
     }
     }
     break;

lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -393,6 +393,13 @@ unsigned TargetLowering::getVectorTypeBreakdown(MVT::ValueType VT,
   return 1;
 }
 
+SDOperand TargetLowering::getPICJumpTableRelocBase(SDOperand Table,
+                                                   SelectionDAG &DAG) const {
+  if (usesGlobalOffsetTable())
+    return DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, getPointerTy());
+  return Table;
+}
+
 //===----------------------------------------------------------------------===//
 //  Optimization Methods
 //===----------------------------------------------------------------------===//

lib/Target/ARM/ARMAsmPrinter.cpp

@@ -693,7 +693,7 @@ void ARMAsmPrinter::printJTBlockOperand(const MachineInstr *MI, int OpNo) {
   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
     MachineBasicBlock *MBB = JTBBs[i];
     if (UseSet && JTSets.insert(MBB).second)
-      printSetLabel(JTI, MO2.getImmedValue(), MBB);
+      printPICJumpTableSetLabel(JTI, MO2.getImmedValue(), MBB);
 
     O << JTEntryDirective << ' ';
     if (UseSet)

lib/Target/X86/X86ATTAsmPrinter.cpp

@@ -498,6 +498,17 @@ void X86ATTAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
   }
 }
 
+void X86ATTAsmPrinter::printPICJumpTableSetLabel(unsigned uid, 
+                                           const MachineBasicBlock *MBB) const {
+  if (!TAI->getSetDirective())
+    return;
+  
+  O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
+    << getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ',';
+  printBasicBlockLabel(MBB, false, false);
+  O << '-' << computePICLabel(getFunctionNumber(), TAI, Subtarget) << '\n';
+}
+
 void X86ATTAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
   std::string label = computePICLabel(getFunctionNumber(), TAI, Subtarget);
   O << label << "\n" << label << ":";

lib/Target/X86/X86ATTAsmPrinter.h

@@ -77,6 +77,12 @@ struct VISIBILITY_HIDDEN X86ATTAsmPrinter : public X86SharedAsmPrinter {
   void printSSECC(const MachineInstr *MI, unsigned Op);
   void printMemReference(const MachineInstr *MI, unsigned Op,
                          const char *Modifier=NULL);
+  void printPICJumpTableSetLabel(unsigned uid,
+                                 const MachineBasicBlock *MBB) const;
+  void printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
+                                 const MachineBasicBlock *MBB) const {
+    AsmPrinter::printPICJumpTableSetLabel(uid, uid2, MBB);
+  }
   void printPICLabel(const MachineInstr *MI, unsigned Op);
   bool runOnMachineFunction(MachineFunction &F);
   

lib/Target/X86/X86ISelLowering.cpp

@@ -650,6 +650,17 @@ X86TargetLowering::X86TargetLowering(TargetMachine &TM)
 }
 
 
+/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
+/// jumptable.
+SDOperand X86TargetLowering::getPICJumpTableRelocBase(SDOperand Table,
+                                                      SelectionDAG &DAG) const {
+  if (usesGlobalOffsetTable())
+    return DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, getPointerTy());
+  if (!Subtarget->isPICStyleRIPRel())
+    return DAG.getNode(X86ISD::GlobalBaseReg, getPointerTy());
+  return Table;
+}
+
 //===----------------------------------------------------------------------===//
 //               Return Value Calling Convention Implementation
 //===----------------------------------------------------------------------===//

lib/Target/X86/X86ISelLowering.h

@@ -296,6 +296,11 @@ namespace llvm {
   public:
     explicit X86TargetLowering(TargetMachine &TM);
 
+    /// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
+    /// jumptable.
+    SDOperand getPICJumpTableRelocBase(SDOperand Table,
+                                       SelectionDAG &DAG) const;
+
     // Return the number of bytes that a function should pop when it returns (in
     // addition to the space used by the return address).
     //

lib/Target/X86/X86IntelAsmPrinter.cpp

@@ -235,6 +235,17 @@ void X86IntelAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
   O << "]";
 }
 
+void X86IntelAsmPrinter::printPICJumpTableSetLabel(unsigned uid, 
+                                           const MachineBasicBlock *MBB) const {
+  if (!TAI->getSetDirective())
+    return;
+  
+  O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
+    << getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ',';
+  printBasicBlockLabel(MBB, false, false);
+  O << '-' << "\"L" << getFunctionNumber() << "$pb\"'\n";
+}
+
 void X86IntelAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
   O << "\"L" << getFunctionNumber() << "$pb\"\n";
   O << "\"L" << getFunctionNumber() << "$pb\":";

lib/Target/X86/X86IntelAsmPrinter.h

@@ -99,6 +99,12 @@ struct VISIBILITY_HIDDEN X86IntelAsmPrinter : public X86SharedAsmPrinter {
   void printSSECC(const MachineInstr *MI, unsigned Op);
   void printMemReference(const MachineInstr *MI, unsigned Op,
                          const char *Modifier=NULL);
+  void printPICJumpTableSetLabel(unsigned uid,
+                                 const MachineBasicBlock *MBB) const;
+  void printPICJumpTableSetLabel(unsigned uid, unsigned uid2,
+                                 const MachineBasicBlock *MBB) const {
+    AsmPrinter::printPICJumpTableSetLabel(uid, uid2, MBB);
+  }
   void printPICLabel(const MachineInstr *MI, unsigned Op);
   bool runOnMachineFunction(MachineFunction &F);
   bool doInitialization(Module &M);