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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76678 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 1 deletions

diff --git a/include/llvm/CodeGen/MachineConstantPool.h b/include/llvm/CodeGen/MachineConstantPool.h
index 99996cf28f..acbbc664dc 100644
--- a/include/llvm/CodeGen/MachineConstantPool.h
+++ b/include/llvm/CodeGen/MachineConstantPool.h
@@ -41,8 +41,22 @@ public:
 
   /// getType - get type of this MachineConstantPoolValue.
   ///
-  inline const Type *getType() const { return Ty; }
+  const Type *getType() const { return Ty; }
 
+  
+  /// getRelocatationInfo - This method classifies the entry according to
+  /// whether or not it may generate a relocation entry.  This must be
+  /// conservative, so if it might codegen to a relocatable entry, it should say
+  /// so.  The return values are:
+  /// 
+  ///  0: This constant pool entry is guaranteed to never have a relocation
+  ///     applied to it (because it holds a simple constant like '4').
+  ///  1: This entry has relocations, but the entries are guaranteed to be
+  ///     resolvable by the static linker, so the dynamic linker will never see
+  ///     them.
+  ///  2: This entry may have arbitrary relocations. 
+  virtual unsigned getRelocatationInfo() const = 0;
+  
   virtual int getExistingMachineCPValue(MachineConstantPool *CP,
                                         unsigned Alignment) = 0;
 
@@ -94,6 +108,19 @@ public:
   }
 
   const Type *getType() const;
+  
+  /// getRelocatationInfo - This method classifies the entry according to
+  /// whether or not it may generate a relocation entry.  This must be
+  /// conservative, so if it might codegen to a relocatable entry, it should say
+  /// so.  The return values are:
+  /// 
+  ///  0: This constant pool entry is guaranteed to never have a relocation
+  ///     applied to it (because it holds a simple constant like '4').
+  ///  1: This entry has relocations, but the entries are guaranteed to be
+  ///     resolvable by the static linker, so the dynamic linker will never see
+  ///     them.
+  ///  2: This entry may have arbitrary relocations. 
+  unsigned getRelocatationInfo() const;
 };
   
 /// The MachineConstantPool class keeps track of constants referenced by a