[PATCH] D122379: [BPF] Don't fetch alignment of llvm.preserve.union.access.index argument

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
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The way the alignment is determined here is not compatible with opaque pointers -- we'd have to thread it through using either align or elementtype attributes.

However, as far as I can tell this alignment is actually never used for this particular intrinsic, so I've dropped the assignment entirely and converted RecordAlignment to MaybeAlign, so we get an assertion failure if it does end up being used.


https://reviews.llvm.org/D122379

Files:
  llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp


Index: llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp
===================================================================
--- llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp
+++ llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp
@@ -124,7 +124,7 @@
   struct CallInfo {
     uint32_t Kind;
     uint32_t AccessIndex;
-    Align RecordAlignment;
+    MaybeAlign RecordAlignment;
     MDNode *Metadata;
     Value *Base;
   };
@@ -170,7 +170,7 @@
                           uint32_t &StartBitOffset, uint32_t &EndBitOffset);
   uint32_t GetFieldInfo(uint32_t InfoKind, DICompositeType *CTy,
                         uint32_t AccessIndex, uint32_t PatchImm,
-                        Align RecordAlignment);
+                        MaybeAlign RecordAlignment);
 
   Value *computeBaseAndAccessKey(CallInst *Call, CallInfo &CInfo,
                                  std::string &AccessKey, MDNode *&BaseMeta);
@@ -300,8 +300,6 @@
       report_fatal_error("Missing metadata for llvm.preserve.union.access.index intrinsic");
     CInfo.AccessIndex = getConstant(Call->getArgOperand(1));
     CInfo.Base = Call->getArgOperand(0);
-    CInfo.RecordAlignment =
-        DL->getABITypeAlign(CInfo.Base->getType()->getPointerElementType());
     return true;
   }
   if (GV->getName().startswith("llvm.preserve.struct.access.index")) {
@@ -619,7 +617,7 @@
                                                DICompositeType *CTy,
                                                uint32_t AccessIndex,
                                                uint32_t PatchImm,
-                                               Align RecordAlignment) {
+                                               MaybeAlign RecordAlignment) {
   if (InfoKind == BPFCoreSharedInfo::FIELD_EXISTENCE)
       return 1;
 
@@ -635,7 +633,7 @@
         PatchImm += MemberTy->getOffsetInBits() >> 3;
       } else {
         unsigned SBitOffset, NextSBitOffset;
-        GetStorageBitRange(MemberTy, RecordAlignment, SBitOffset,
+        GetStorageBitRange(MemberTy, *RecordAlignment, SBitOffset,
                            NextSBitOffset);
         PatchImm += SBitOffset >> 3;
       }
@@ -654,7 +652,8 @@
         return SizeInBits >> 3;
 
       unsigned SBitOffset, NextSBitOffset;
-      GetStorageBitRange(MemberTy, RecordAlignment, SBitOffset, NextSBitOffset);
+      GetStorageBitRange(MemberTy, *RecordAlignment, SBitOffset,
+                         NextSBitOffset);
       SizeInBits = NextSBitOffset - SBitOffset;
       if (SizeInBits & (SizeInBits - 1))
         report_fatal_error("Unsupported field expression for llvm.bpf.preserve.field.info");
@@ -714,7 +713,7 @@
     }
 
     unsigned SBitOffset, NextSBitOffset;
-    GetStorageBitRange(MemberTy, RecordAlignment, SBitOffset, NextSBitOffset);
+    GetStorageBitRange(MemberTy, *RecordAlignment, SBitOffset, NextSBitOffset);
     if (NextSBitOffset - SBitOffset > 64)
       report_fatal_error("too big field size for llvm.bpf.preserve.field.info");
 
@@ -745,7 +744,7 @@
     }
 
     unsigned SBitOffset, NextSBitOffset;
-    GetStorageBitRange(MemberTy, RecordAlignment, SBitOffset, NextSBitOffset);
+    GetStorageBitRange(MemberTy, *RecordAlignment, SBitOffset, NextSBitOffset);
     if (NextSBitOffset - SBitOffset > 64)
       report_fatal_error("too big field size for llvm.bpf.preserve.field.info");
 


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