add an API so target-independent codegen can determine if a constant

pool entry will require relocations against it.  I implemented this
conservatively for ARM, someone who is knowledgable about it should
see if this can be improved.

llvm-svn: 76678

2 files changed, 27 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index 599efb8bd27..e6ae7dc2245 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -539,10 +539,29 @@ void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
 
 const Type *MachineConstantPoolEntry::getType() const {
   if (isMachineConstantPoolEntry())
-      return Val.MachineCPVal->getType();
+    return Val.MachineCPVal->getType();
   return Val.ConstVal->getType();
 }
 
+
+unsigned MachineConstantPoolEntry::getRelocatationInfo() const {
+  if (isMachineConstantPoolEntry())
+    return Val.MachineCPVal->getRelocatationInfo();
+  
+  // FIXME: This API sucks.
+  
+  // If no relocations, return 0.
+  if (!Val.ConstVal->ContainsRelocations())
+    return 0;
+
+  // If it contains no global relocations, return 1.
+  if (!Val.ConstVal->ContainsRelocations(Reloc::Global))
+    return 1;
+
+  // Otherwise, it has general relocations.
+  return 2;
+}
+
 MachineConstantPool::~MachineConstantPool() {
   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
     if (Constants[i].isMachineConstantPoolEntry())
diff --git a/llvm/lib/Target/ARM/ARMConstantPoolValue.h b/llvm/lib/Target/ARM/ARMConstantPoolValue.h
index abf7339646b..a9308898c86 100644
--- a/llvm/lib/Target/ARM/ARMConstantPoolValue.h
+++ b/llvm/lib/Target/ARM/ARMConstantPoolValue.h
@@ -65,6 +65,13 @@ public:
   bool isStub() const { return Kind == ARMCP::CPStub; }
   unsigned char getPCAdjustment() const { return PCAdjust; }
 
+  virtual unsigned getRelocatationInfo() const {
+    // FIXME: This is conservatively claiming that these entries require a
+    // relocation, we may be able to do better than this.
+    return 2;
+  }
+
+  
   virtual int getExistingMachineCPValue(MachineConstantPool *CP,
                                         unsigned Alignment);