Add a flag to disable jump table generation (all
switches use the binary search algorithm) for
environments that don't support it.  PPC64 JIT
is such an environment; turn the flag on for that.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54248 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 1fe2e8c..fcf235c 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -43,7 +43,7 @@
   : TargetLowering(TM), PPCSubTarget(*TM.getSubtargetImpl()) {
     
   setPow2DivIsCheap();
-  
+
   // Use _setjmp/_longjmp instead of setjmp/longjmp.
   setUseUnderscoreSetJmp(true);
   setUseUnderscoreLongJmp(true);
diff --git a/lib/Target/PowerPC/PPCTargetMachine.cpp b/lib/Target/PowerPC/PPCTargetMachine.cpp
index 8fa0809..7c90eca 100644
--- a/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Module.h"
 #include "llvm/PassManager.h"
 #include "llvm/Target/TargetMachineRegistry.h"
+#include "llvm/Target/TargetOptions.h"
 using namespace llvm;
 
 // Register the targets
@@ -144,6 +145,9 @@
     // instructions to materialize arbitrary global variable + function +
     // constant pool addresses.
     setRelocationModel(Reloc::PIC_);
+    // Temporary workaround for the inability of PPC64 JIT to handle jump
+    // tables.
+    DisableJumpTables = true;      
   } else {
     setRelocationModel(Reloc::Static);
   }
diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp
index 0764968..600a120 100644
--- a/lib/Target/TargetMachine.cpp
+++ b/lib/Target/TargetMachine.cpp
@@ -39,6 +39,7 @@
   unsigned StackAlignment;
   bool RealignStack;
   bool VerboseAsm;
+  bool DisableJumpTables;
 }
 
 static cl::opt<bool, true> PrintCode("print-machineinstrs",
@@ -156,6 +157,11 @@
            cl::location(VerboseAsm),
            cl::init(false));
 
+static cl::opt<bool, true>
+DisableSwitchTables(cl::Hidden, "disable-jump-tables", 
+           cl::desc("Do not generate jump tables."),
+           cl::location(DisableJumpTables),
+           cl::init(false));
 
 //---------------------------------------------------------------------------
 // TargetMachine Class