[llvm] c48b464 - [BPF] Don't fetch alignment of llvm.preserve.union.access.index argument

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-03-25T09:53:30+01:00
New Revision: c48b4641c7baf9f7280d352c13299b3aa0203179

URL: https://github.com/llvm/llvm-project/commit/c48b4641c7baf9f7280d352c13299b3aa0203179
DIFF: https://github.com/llvm/llvm-project/commit/c48b4641c7baf9f7280d352c13299b3aa0203179.diff

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

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.

Differential Revision: https://reviews.llvm.org/D122379

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp b/llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp
index 80ec64d63c77a..64cdb51bdf819 100644
--- a/llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp
+++ b/llvm/lib/Target/BPF/BPFAbstractMemberAccess.cpp
@@ -124,7 +124,7 @@ class BPFAbstractMemberAccess final {
   struct CallInfo {
     uint32_t Kind;
     uint32_t AccessIndex;
-    Align RecordAlignment;
+    MaybeAlign RecordAlignment;
     MDNode *Metadata;
     Value *Base;
   };
@@ -170,7 +170,7 @@ class BPFAbstractMemberAccess final {
                           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 @@ bool BPFAbstractMemberAccess::IsPreserveDIAccessIndexCall(const CallInst *Call,
       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 @@ uint32_t BPFAbstractMemberAccess::GetFieldInfo(uint32_t InfoKind,
                                                DICompositeType *CTy,
                                                uint32_t AccessIndex,
                                                uint32_t PatchImm,
-                                               Align RecordAlignment) {
+                                               MaybeAlign RecordAlignment) {
   if (InfoKind == BPFCoreSharedInfo::FIELD_EXISTENCE)
       return 1;
 
@@ -635,7 +633,7 @@ uint32_t BPFAbstractMemberAccess::GetFieldInfo(uint32_t InfoKind,
         PatchImm += MemberTy->getOffsetInBits() >> 3;
       } else {
         unsigned SBitOffset, NextSBitOffset;
-        GetStorageBitRange(MemberTy, RecordAlignment, SBitOffset,
+        GetStorageBitRange(MemberTy, *RecordAlignment, SBitOffset,
                            NextSBitOffset);
         PatchImm += SBitOffset >> 3;
       }
@@ -654,7 +652,8 @@ uint32_t BPFAbstractMemberAccess::GetFieldInfo(uint32_t InfoKind,
         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 @@ uint32_t BPFAbstractMemberAccess::GetFieldInfo(uint32_t InfoKind,
     }
 
     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 @@ uint32_t BPFAbstractMemberAccess::GetFieldInfo(uint32_t InfoKind,
     }
 
     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");