[JITLink][AARCH64][NFC] Create isLoadStoreImm12 function by splitting getPageOffset12Shift

[sunho]

Summary

Split getPageOffset12Shift function to get isLoadStoreImm12 util function which will be used for validating elf/aarch64 ldst relocation types.

[sunho]

Truncated diff

[sgraenitz]

LGTM!

[lhames]

LGTM.

llvm/include/llvm/ExecutionEngine/JITLink/aarch64.h

enum EdgeKind_aarch64 : Edge::Kind {
   NegDelta32,
   NegDelta64,
 };
 
 /// Returns a string name for the given aarch64 edge. For debugging purposes
 /// only
 const char *getEdgeKindName(Edge::Kind K);
 
+bool isLoadStoreImm12(uint32_t Instr);
+
 unsigned getPageOffset12Shift(uint32_t Instr);
 
 Error applyFixup(LinkGraph &G, Block &B, const Edge &E);
 
 } // namespace aarch64
 } // namespace jitlink
 } // namespace llvm
 
 #endif // LLVM_EXECUTIONENGINE_JITLINK_AARCH64_H

llvm/lib/ExecutionEngine/JITLink/aarch64.cpp

 #include "llvm/ExecutionEngine/JITLink/aarch64.h"
 
 #define DEBUG_TYPE "jitlink"
 
 namespace llvm {
 namespace jitlink {
 namespace aarch64 {
 
-unsigned getPageOffset12Shift(uint32_t Instr) {
+bool isLoadStoreImm12(uint32_t Instr) {
   constexpr uint32_t LoadStoreImm12Mask = 0x3b000000;
+  return (Instr & LoadStoreImm12Mask) == 0x39000000;
+}
+
+unsigned getPageOffset12Shift(uint32_t Instr) {
   constexpr uint32_t Vec128Mask = 0x04800000;
 
-  if ((Instr & LoadStoreImm12Mask) == 0x39000000) {
+  if (isLoadStoreImm12(Instr)) {
     uint32_t ImplicitShift = Instr >> 30;
     if (ImplicitShift == 0)
       if ((Instr & Vec128Mask) == Vec128Mask)
         ImplicitShift = 4;
 
     return ImplicitShift;
   }
-
-  return 0;
 }
 
 Error applyFixup(LinkGraph &G, Block &B, const Edge &E) {
   using namespace support;
 
   char *BlockWorkingMem = B.getAlreadyMutableContent().data();
   char *FixupPtr = BlockWorkingMem + E.getOffset();
   orc::ExecutorAddr FixupAddress = B.getAddress() + E.getOffset();