MCAsmBackend::applyFixup: Change Data to indicate the relocated location

`Data` now references the first byte of the fixup offset within the current fragment.

MCAssembler::layout asserts that the fixup offset is within either the
fixed-size content or the optional variable-size tail, as this is the
most the generic code can validate without knowing the target-specific
fixup size.

Many backends applyFixup assert
```
assert(Offset + Size <= F.getSize() && "Invalid fixup offset!");
```

This refactoring allows a subsequent change to move the fixed-size
content outside of MCSection::ContentStorage, fixing the
-fsanitize=pointer-overflow issue of #150846

Pull Request: https://github.com/llvm/llvm-project/pull/151724

llvm/include/llvm/MC/MCAsmBackend.h

@@ -117,14 +117,13 @@ public:
   void maybeAddReloc(const MCFragment &, const MCFixup &, const MCValue &,
                      uint64_t &Value, bool IsResolved);
 
-  /// Determine if a relocation is required. In addition,
+  // Determine if a relocation is required. In addition, apply `Value` to the
-  /// Apply the \p Value for given \p Fixup into the provided data fragment, at
+  // `Data` fragment at the specified fixup offset if applicable. `Data` points
-  /// the offset specified by the fixup and following the fixup kind as
+  // to the first byte of the fixup offset, which may be at the content's end if
-  /// appropriate. Errors (such as an out of range fixup value) should be
+  // the fixup is zero-sized.
-  /// reported via \p Ctx.
   virtual void applyFixup(const MCFragment &, const MCFixup &,
-                          const MCValue &Target, MutableArrayRef<char> Data,
+                          const MCValue &Target, uint8_t *Data, uint64_t Value,
-                          uint64_t Value, bool IsResolved) = 0;
+                          bool IsResolved) = 0;
 
   /// @}
 

llvm/include/llvm/MC/MCAssembler.h

@@ -99,8 +99,7 @@ private:
   /// \param RecordReloc Record relocation if needed.
   /// relocation.
   bool evaluateFixup(const MCFragment &F, MCFixup &Fixup, MCValue &Target,
-                     uint64_t &Value, bool RecordReloc,
+                     uint64_t &Value, bool RecordReloc, uint8_t *Data) const;
-                     MutableArrayRef<char> Contents) const;
 
   /// Check whether a fixup can be satisfied, or whether it needs to be relaxed
   /// (increased in size, in order to hold its value correctly).

llvm/lib/MC/MCAssembler.cpp

@@ -141,8 +141,7 @@ bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const {
 
 bool MCAssembler::evaluateFixup(const MCFragment &F, MCFixup &Fixup,
                                 MCValue &Target, uint64_t &Value,
-                                bool RecordReloc,
+                                bool RecordReloc, uint8_t *Data) const {
-                                MutableArrayRef<char> Contents) const {
   if (RecordReloc)
     ++stats::Fixups;
 
@@ -187,7 +186,7 @@ bool MCAssembler::evaluateFixup(const MCFragment &F, MCFixup &Fixup,
 
   if (IsResolved && mc::isRelocRelocation(Fixup.getKind()))
     IsResolved = false;
-  getBackend().applyFixup(F, Fixup, Target, Contents, Value, IsResolved);
+  getBackend().applyFixup(F, Fixup, Target, Data, Value, IsResolved);
   return true;
 }
 
@@ -705,21 +704,25 @@ void MCAssembler::layout() {
       for (MCFixup &Fixup : F.getFixups()) {
         uint64_t FixedValue;
         MCValue Target;
+        assert(mc::isRelocRelocation(Fixup.getKind()) ||
+               Fixup.getOffset() <= F.getFixedSize());
+        auto *Data =
+            reinterpret_cast<uint8_t *>(Contents.data() + Fixup.getOffset());
         evaluateFixup(F, Fixup, Target, FixedValue,
-                      /*RecordReloc=*/true, Contents);
+                      /*RecordReloc=*/true, Data);
       }
-      if (F.getVarFixups().size()) {
       // In the variable part, fixup offsets are relative to the fixed part's
-        // start. Extend the variable contents to the left to account for the
+      // start.
-        // fixed part size.
-        Contents = MutableArrayRef(F.getParent()->ContentStorage)
-                       .slice(F.VarContentStart - Contents.size(), F.getSize());
       for (MCFixup &Fixup : F.getVarFixups()) {
         uint64_t FixedValue;
         MCValue Target;
+        assert(mc::isRelocRelocation(Fixup.getKind()) ||
+               (Fixup.getOffset() >= F.getFixedSize() &&
+                Fixup.getOffset() <= F.getSize()));
+        auto *Data = reinterpret_cast<uint8_t *>(
+            F.getVarContents().data() + (Fixup.getOffset() - F.getFixedSize()));
         evaluateFixup(F, Fixup, Target, FixedValue,
-                        /*RecordReloc=*/true, Contents);
+                      /*RecordReloc=*/true, Data);
-        }
       }
     }
   }

llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp

@@ -79,8 +79,7 @@ public:
   }
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool fixupNeedsRelaxation(const MCFixup &Fixup,
                             uint64_t Value) const override;
@@ -421,9 +420,8 @@ static bool shouldForceRelocation(const MCFixup &Fixup) {
 }
 
 void AArch64AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                   const MCValue &Target,
+                                   const MCValue &Target, uint8_t *Data,
-                                   MutableArrayRef<char> Data, uint64_t Value,
+                                   uint64_t Value, bool IsResolved) {
-                                   bool IsResolved) {
   if (shouldForceRelocation(Fixup))
     IsResolved = false;
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
@@ -460,8 +458,8 @@ void AArch64AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // Used to point to big endian bytes.
   unsigned FulleSizeInBytes = getFixupKindContainereSizeInBytes(Fixup.getKind());
@@ -471,15 +469,16 @@ void AArch64AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   if (FulleSizeInBytes == 0) {
     // Handle as little-endian
     for (unsigned i = 0; i != NumBytes; ++i) {
-      Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff);
+      Data[i] |= uint8_t((Value >> (i * 8)) & 0xff);
     }
   } else {
     // Handle as big-endian
-    assert((Offset + FulleSizeInBytes) <= Data.size() && "Invalid fixup size!");
+    assert(Fixup.getOffset() + FulleSizeInBytes <= F.getSize() &&
+           "Invalid fixup size!");
     assert(NumBytes <= FulleSizeInBytes && "Invalid fixup size!");
     for (unsigned i = 0; i != NumBytes; ++i) {
       unsigned Idx = FulleSizeInBytes - 1 - i;
-      Data[Offset + Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
+      Data[Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
     }
   }
 
@@ -492,9 +491,9 @@ void AArch64AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
     // If the immediate is negative, generate MOVN else MOVZ.
     // (Bit 30 = 0) ==> MOVN, (Bit 30 = 1) ==> MOVZ.
     if (SignedValue < 0)
-      Data[Offset + 3] &= ~(1 << 6);
+      Data[3] &= ~(1 << 6);
     else
-      Data[Offset + 3] |= (1 << 6);
+      Data[3] |= (1 << 6);
   }
 }
 

llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp

@@ -33,8 +33,7 @@ public:
   AMDGPUAsmBackend(const Target &T) : MCAsmBackend(llvm::endianness::little) {}
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
   bool fixupNeedsRelaxation(const MCFixup &Fixup,
                             uint64_t Value) const override;
 
@@ -129,9 +128,8 @@ static uint64_t adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
 }
 
 void AMDGPUAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                  const MCValue &Target,
+                                  const MCValue &Target, uint8_t *Data,
-                                  MutableArrayRef<char> Data, uint64_t Value,
+                                  uint64_t Value, bool IsResolved) {
-                                  bool IsResolved) {
   if (Target.getSpecifier())
     IsResolved = false;
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
@@ -148,13 +146,13 @@ void AMDGPUAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   Value <<= Info.TargetOffset;
 
   unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
-  uint32_t Offset = Fixup.getOffset();
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // For each byte of the fragment that the fixup touches, mask in the bits from
   // the fixup value.
   for (unsigned i = 0; i != NumBytes; ++i)
-    Data[Offset + i] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
+    Data[i] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
 }
 
 std::optional<MCFixupKind>

llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp

@@ -1108,9 +1108,8 @@ std::optional<bool> ARMAsmBackend::evaluateFixup(const MCFragment &F,
 }
 
 void ARMAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                               const MCValue &Target,
+                               const MCValue &Target, uint8_t *Data,
-                               MutableArrayRef<char> Data, uint64_t Value,
+                               uint64_t Value, bool IsResolved) {
-                               bool IsResolved) {
   if (IsResolved && shouldForceRelocation(Fixup, Target))
     IsResolved = false;
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
@@ -1124,14 +1123,15 @@ void ARMAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
     return; // Doesn't change encoding.
   const unsigned NumBytes = getFixupKindNumBytes(Kind);
 
-  unsigned Offset = Fixup.getOffset();
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // Used to point to big endian bytes.
   unsigned FullSizeBytes;
   if (Endian == llvm::endianness::big) {
     FullSizeBytes = getFixupKindContainerSizeBytes(Kind);
-    assert((Offset + FullSizeBytes) <= Data.size() && "Invalid fixup size!");
+    assert(Fixup.getOffset() + FullSizeBytes <= F.getSize() &&
+           "Invalid fixup size!");
     assert(NumBytes <= FullSizeBytes && "Invalid fixup size!");
   }
 
@@ -1141,7 +1141,7 @@ void ARMAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   for (unsigned i = 0; i != NumBytes; ++i) {
     unsigned Idx =
         Endian == llvm::endianness::little ? i : (FullSizeBytes - 1 - i);
-    Data[Offset + Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
+    Data[Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h

@@ -40,8 +40,7 @@ public:
   std::optional<bool> evaluateFixup(const MCFragment &, MCFixup &, MCValue &,
                                     uint64_t &) override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   unsigned getRelaxedOpcode(unsigned Op, const MCSubtargetInfo &STI) const;
 

llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp

@@ -368,9 +368,8 @@ AVRAsmBackend::createObjectTargetWriter() const {
 }
 
 void AVRAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                               const MCValue &Target,
+                               const MCValue &Target, uint8_t *Data,
-                               MutableArrayRef<char> Data, uint64_t Value,
+                               uint64_t Value, bool IsResolved) {
-                               bool IsResolved) {
   // AVR sets the fixup value to bypass the assembly time overflow with a
   // relocation.
   if (IsResolved) {
@@ -397,14 +396,14 @@ void AVRAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   for (unsigned i = 0; i < NumBytes; ++i) {
     uint8_t mask = (((Value >> (i * 8)) & 0xff));
-    Data[Offset + i] |= mask;
+    Data[i] |= mask;
   }
 }
 

llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.h

@@ -38,8 +38,7 @@ public:
   createObjectTargetWriter() const override;
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;

llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp

@@ -27,8 +27,7 @@ public:
   ~BPFAsmBackend() override = default;
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override;
@@ -66,35 +65,32 @@ bool BPFAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
 }
 
 void BPFAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                               const MCValue &Target,
+                               const MCValue &Target, uint8_t *Data,
-                               MutableArrayRef<char> Data, uint64_t Value,
+                               uint64_t Value, bool IsResolved) {
-                               bool IsResolved) {
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
   if (Fixup.getKind() == FK_SecRel_8) {
     // The Value is 0 for global variables, and the in-section offset
     // for static variables. Write to the immediate field of the inst.
     assert(Value <= UINT32_MAX);
-    support::endian::write<uint32_t>(&Data[Fixup.getOffset() + 4],
+    support::endian::write<uint32_t>(Data + 4, static_cast<uint32_t>(Value),
-                                     static_cast<uint32_t>(Value),
                                      Endian);
   } else if (Fixup.getKind() == FK_Data_4 && !Fixup.isPCRel()) {
-    support::endian::write<uint32_t>(&Data[Fixup.getOffset()], Value, Endian);
+    support::endian::write<uint32_t>(Data, Value, Endian);
   } else if (Fixup.getKind() == FK_Data_8) {
-    support::endian::write<uint64_t>(&Data[Fixup.getOffset()], Value, Endian);
+    support::endian::write<uint64_t>(Data, Value, Endian);
   } else if (Fixup.getKind() == FK_Data_4 && Fixup.isPCRel()) {
     Value = (uint32_t)((Value - 8) / 8);
     if (Endian == llvm::endianness::little) {
-      Data[Fixup.getOffset() + 1] = 0x10;
+      Data[1] = 0x10;
-      support::endian::write32le(&Data[Fixup.getOffset() + 4], Value);
+      support::endian::write32le(Data + 4, Value);
     } else {
-      Data[Fixup.getOffset() + 1] = 0x1;
+      Data[1] = 0x1;
-      support::endian::write32be(&Data[Fixup.getOffset() + 4], Value);
+      support::endian::write32be(Data + 4, Value);
     }
   } else if (Fixup.getKind() == BPF::FK_BPF_PCRel_4) {
     // The input Value represents the number of bytes.
     Value = (uint32_t)((Value - 8) / 8);
-    support::endian::write<uint32_t>(&Data[Fixup.getOffset() + 4], Value,
+    support::endian::write<uint32_t>(Data + 4, Value, Endian);
-                                     Endian);
   } else {
     assert(Fixup.getKind() == FK_Data_2 && Fixup.isPCRel());
 
@@ -103,8 +99,7 @@ void BPFAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
       report_fatal_error("Branch target out of insn range");
 
     Value = (uint16_t)((Value - 8) / 8);
-    support::endian::write<uint16_t>(&Data[Fixup.getOffset() + 2], Value,
+    support::endian::write<uint16_t>(Data + 2, Value, Endian);
-                                     Endian);
   }
 }
 

llvm/lib/Target/CSKY/MCTargetDesc/CSKYAsmBackend.cpp

@@ -197,9 +197,8 @@ std::optional<bool> CSKYAsmBackend::evaluateFixup(const MCFragment &F,
 }
 
 void CSKYAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                const MCValue &Target,
+                                const MCValue &Target, uint8_t *Data,
-                                MutableArrayRef<char> Data, uint64_t Value,
+                                uint64_t Value, bool IsResolved) {
-                                bool IsResolved) {
   if (IsResolved && shouldForceRelocation(Fixup, Target))
     IsResolved = false;
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
@@ -217,10 +216,10 @@ void CSKYAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
   unsigned NumBytes = alignTo(Info.TargetSize + Info.TargetOffset, 8) / 8;
 
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
+         "Invalid fixup offset!");
 
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
@@ -228,14 +227,14 @@ void CSKYAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   bool IsInstFixup = (Kind >= FirstTargetFixupKind);
 
   if (IsLittleEndian && IsInstFixup && (NumBytes == 4)) {
-    Data[Offset + 0] |= uint8_t((Value >> 16) & 0xff);
+    Data[0] |= uint8_t((Value >> 16) & 0xff);
-    Data[Offset + 1] |= uint8_t((Value >> 24) & 0xff);
+    Data[1] |= uint8_t((Value >> 24) & 0xff);
-    Data[Offset + 2] |= uint8_t(Value & 0xff);
+    Data[2] |= uint8_t(Value & 0xff);
-    Data[Offset + 3] |= uint8_t((Value >> 8) & 0xff);
+    Data[3] |= uint8_t((Value >> 8) & 0xff);
   } else {
     for (unsigned I = 0; I != NumBytes; I++) {
       unsigned Idx = IsLittleEndian ? I : (NumBytes - 1 - I);
-      Data[Offset + Idx] |= uint8_t((Value >> (I * 8)) & 0xff);
+      Data[Idx] |= uint8_t((Value >> (I * 8)) & 0xff);
     }
   }
 }

llvm/lib/Target/CSKY/MCTargetDesc/CSKYAsmBackend.h

@@ -25,8 +25,7 @@ public:
   std::optional<bool> evaluateFixup(const MCFragment &, MCFixup &, MCValue &,
                                     uint64_t &) override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
 

llvm/lib/Target/DirectX/MCTargetDesc/DirectXMCTargetDesc.cpp

@@ -78,8 +78,7 @@ public:
   ~DXILAsmBackend() override = default;
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override {}
-                  bool IsResolved) override {}
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override {

llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp

@@ -402,8 +402,7 @@ public:
   }
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &,
-                  MutableArrayRef<char> Data, uint64_t FixupValue,
+                  uint8_t *Data, uint64_t FixupValue, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool isInstRelaxable(MCInst const &HMI) const {
     const MCInstrDesc &MCID = HexagonMCInstrInfo::getDesc(*MCII, HMI);
@@ -649,8 +648,7 @@ public:
 } // namespace
 
 void HexagonAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                   const MCValue &Target,
+                                   const MCValue &Target, uint8_t *InstAddr,
-                                   MutableArrayRef<char> Data,
                                    uint64_t FixupValue, bool IsResolved) {
   if (IsResolved && shouldForceRelocation(Fixup))
     IsResolved = false;
@@ -667,10 +665,9 @@ void HexagonAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
 
   // LLVM gives us an encoded value, we have to convert it back
   // to a real offset before we can use it.
-  uint32_t Offset = Fixup.getOffset();
   unsigned NumBytes = getFixupKindNumBytes(Kind);
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  char *InstAddr = Data.data() + Offset;
+         "Invalid fixup offset!");
 
   Value = adjustFixupValue(Kind, FixupValue);
   if (!Value)
@@ -757,8 +754,8 @@ void HexagonAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
       uint32_t OldData = 0; for (unsigned i = 0; i < NumBytes; i++) OldData |=
                             (InstAddr[i] << (i * 8)) & (0xff << (i * 8));
       dbgs() << "\tBValue=0x"; dbgs().write_hex(Value) << ": AValue=0x";
-      dbgs().write_hex(FixupValue)
+      dbgs().write_hex(FixupValue) << ": Offset=" << Fixup.getOffset()
-      << ": Offset=" << Offset << ": Size=" << Data.size() << ": OInst=0x";
+                                   << ": Size=" << F.getSize() << ": OInst=0x";
       dbgs().write_hex(OldData) << ": Reloc=0x"; dbgs().write_hex(Reloc););
 
   // For each byte of the fragment that the fixup touches, mask in the

llvm/lib/Target/Lanai/MCTargetDesc/LanaiAsmBackend.cpp

@@ -48,8 +48,7 @@ public:
       : MCAsmBackend(llvm::endianness::big), OSType(OST) {}
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override;
@@ -72,9 +71,8 @@ bool LanaiAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
 }
 
 void LanaiAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                 const MCValue &Target,
+                                 const MCValue &Target, uint8_t *Data,
-                                 MutableArrayRef<char> Data, uint64_t Value,
+                                 uint64_t Value, bool IsResolved) {
-                                 bool IsResolved) {
   if (!IsResolved)
     Asm->getWriter().recordRelocation(F, Fixup, Target, Value);
 
@@ -85,7 +83,6 @@ void LanaiAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
 
   // Where in the object and where the number of bytes that need
   // fixing up
-  unsigned Offset = Fixup.getOffset();
   unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
   unsigned FullSize = 4;
 
@@ -95,8 +92,7 @@ void LanaiAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Load instruction and apply value
   for (unsigned i = 0; i != NumBytes; ++i) {
     unsigned Idx = (FullSize - 1 - i);
-    CurVal |= static_cast<uint64_t>(static_cast<uint8_t>(Data[Offset + Idx]))
+    CurVal |= static_cast<uint64_t>(static_cast<uint8_t>(Data[Idx])) << (i * 8);
-              << (i * 8);
   }
 
   uint64_t Mask =
@@ -106,7 +102,7 @@ void LanaiAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Write out the fixed up bytes back to the code/data bits.
   for (unsigned i = 0; i != NumBytes; ++i) {
     unsigned Idx = (FullSize - 1 - i);
-    Data[Offset + Idx] = static_cast<uint8_t>((CurVal >> (i * 8)) & 0xff);
+    Data[Idx] = static_cast<uint8_t>((CurVal >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp

@@ -131,19 +131,18 @@ static uint64_t adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
   }
 }
 
-static void fixupLeb128(MCContext &Ctx, const MCFixup &Fixup,
+static void fixupLeb128(MCContext &Ctx, const MCFixup &Fixup, uint8_t *Data,
-                        MutableArrayRef<char> Data, uint64_t Value) {
+                        uint64_t Value) {
   unsigned I;
-  for (I = 0; I != Data.size() && Value; ++I, Value >>= 7)
+  for (I = 0; Value; ++I, Value >>= 7)
     Data[I] |= uint8_t(Value & 0x7f);
   if (Value)
     Ctx.reportError(Fixup.getLoc(), "Invalid uleb128 value!");
 }
 
 void LoongArchAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                     const MCValue &Target,
+                                     const MCValue &Target, uint8_t *Data,
-                                     MutableArrayRef<char> Data, uint64_t Value,
+                                     uint64_t Value, bool IsResolved) {
-                                     bool IsResolved) {
   if (IsResolved && shouldForceRelocation(Fixup, Target))
     IsResolved = false;
   IsResolved = addReloc(F, Fixup, Target, Value, IsResolved);
@@ -166,14 +165,14 @@ void LoongArchAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
   unsigned NumBytes = alignTo(Info.TargetSize + Info.TargetOffset, 8) / 8;
 
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
+         "Invalid fixup offset!");
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   for (unsigned I = 0; I != NumBytes; ++I) {
-    Data[Offset + I] |= uint8_t((Value >> (I * 8)) & 0xff);
+    Data[I] |= uint8_t((Value >> (I * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h

@@ -42,8 +42,7 @@ public:
                 uint64_t &FixedValue, bool IsResolved);
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool shouldForceRelocation(const MCFixup &Fixup, const MCValue &Target);
 

llvm/lib/Target/M68k/MCTargetDesc/M68kAsmBackend.cpp

@@ -53,8 +53,7 @@ public:
                               .Default(false)) {}
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool mayNeedRelaxation(unsigned Opcode, ArrayRef<MCOperand> Operands,
                          const MCSubtargetInfo &STI) const override;
@@ -78,9 +77,8 @@ public:
 } // end anonymous namespace
 
 void M68kAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                const MCValue &Target,
+                                const MCValue &Target, uint8_t *Data,
-                                MutableArrayRef<char> Data, uint64_t Value,
+                                uint64_t Value, bool IsResolved) {
-                                bool IsResolved) {
   if (!IsResolved)
     Asm->getWriter().recordRelocation(F, Fixup, Target, Value);
 
@@ -95,8 +93,7 @@ void M68kAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
 
   // Write in Big Endian
   for (unsigned i = 0; i != Size; ++i)
-    Data[Fixup.getOffset() + i] =
+    Data[i] = uint8_t(static_cast<int64_t>(Value) >> ((Size - i - 1) * 8));
-        uint8_t(static_cast<int64_t>(Value) >> ((Size - i - 1) * 8));
 }
 
 /// cc—Carry clear      GE—Greater than or equal

llvm/lib/Target/MSP430/MCTargetDesc/MSP430AsmBackend.cpp

@@ -36,8 +36,7 @@ public:
   ~MSP430AsmBackend() override = default;
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override {
@@ -105,9 +104,8 @@ uint64_t MSP430AsmBackend::adjustFixupValue(const MCFixup &Fixup,
 }
 
 void MSP430AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                  const MCValue &Target,
+                                  const MCValue &Target, uint8_t *Data,
-                                  MutableArrayRef<char> Data, uint64_t Value,
+                                  uint64_t Value, bool IsResolved) {
-                                  bool IsResolved) {
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
   Value = adjustFixupValue(Fixup, Value, getContext());
   MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
@@ -117,15 +115,14 @@ void MSP430AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
   unsigned NumBytes = alignTo(Info.TargetSize + Info.TargetOffset, 8) / 8;
-
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   for (unsigned i = 0; i != NumBytes; ++i) {
-    Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff);
+    Data[i] |= uint8_t((Value >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp

@@ -283,9 +283,8 @@ static bool shouldForceRelocation(const MCFixup &Fixup) {
 /// data fragment, at the offset specified by the fixup and following the
 /// fixup kind as appropriate.
 void MipsAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                const MCValue &Target,
+                                const MCValue &Target, uint8_t *Data,
-                                MutableArrayRef<char> Data, uint64_t Value,
+                                uint64_t Value, bool IsResolved) {
-                                bool IsResolved) {
   if (shouldForceRelocation(Fixup))
     IsResolved = false;
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
@@ -297,7 +296,6 @@ void MipsAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
     return; // Doesn't change encoding.
 
   // Where do we start in the object
-  unsigned Offset = Fixup.getOffset();
   // Number of bytes we need to fixup
   unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
   // Used to point to big endian bytes
@@ -328,7 +326,7 @@ void MipsAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
     unsigned Idx = Endian == llvm::endianness::little
                        ? (microMipsLEByteOrder ? calculateMMLEIndex(i) : i)
                        : (FullSize - 1 - i);
-    CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8);
+    CurVal |= (uint64_t)((uint8_t)Data[Idx]) << (i * 8);
   }
 
   uint64_t Mask = ((uint64_t)(-1) >>
@@ -340,7 +338,7 @@ void MipsAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
     unsigned Idx = Endian == llvm::endianness::little
                        ? (microMipsLEByteOrder ? calculateMMLEIndex(i) : i)
                        : (FullSize - 1 - i);
-    Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff);
+    Data[Idx] = (uint8_t)((CurVal >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.h

@@ -40,8 +40,7 @@ public:
   createObjectTargetWriter() const override;
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;

llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp

@@ -93,8 +93,8 @@ public:
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
 
   void applyFixup(const MCFragment &, const MCFixup &Fixup,
-                  const MCValue &Target, MutableArrayRef<char> Data,
+                  const MCValue &Target, uint8_t *Data, uint64_t Value,
-                  uint64_t Value, bool IsResolved) override;
+                  bool IsResolved) override;
 
   bool shouldForceRelocation(const MCFixup &Fixup, const MCValue &Target) {
     // If there is a @ specifier, unless it is optimized out (e.g. constant @l),
@@ -185,9 +185,8 @@ MCFixupKindInfo PPCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
 }
 
 void PPCAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                               const MCValue &TargetVal,
+                               const MCValue &TargetVal, uint8_t *Data,
-                               MutableArrayRef<char> Data, uint64_t Value,
+                               uint64_t Value, bool IsResolved) {
-                               bool IsResolved) {
   // In PPC64 ELFv1, .quad .TOC.@tocbase in the .opd section is expected to
   // reference the null symbol.
   auto Target = TargetVal;
@@ -205,7 +204,6 @@ void PPCAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   if (!Value)
     return; // Doesn't change encoding.
 
-  unsigned Offset = Fixup.getOffset();
   unsigned NumBytes = getFixupKindNumBytes(Kind);
 
   // For each byte of the fragment that the fixup touches, mask in the bits
@@ -213,7 +211,7 @@ void PPCAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // bitfields above.
   for (unsigned i = 0; i != NumBytes; ++i) {
     unsigned Idx = Endian == llvm::endianness::little ? i : (NumBytes - 1 - i);
-    Data[Offset + i] |= uint8_t((Value >> (Idx * 8)) & 0xff);
+    Data[i] |= uint8_t((Value >> (Idx * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp

@@ -881,9 +881,8 @@ bool RISCVAsmBackend::addReloc(const MCFragment &F, const MCFixup &Fixup,
 }
 
 void RISCVAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                 const MCValue &Target,
+                                 const MCValue &Target, uint8_t *Data,
-                                 MutableArrayRef<char> Data, uint64_t Value,
+                                 uint64_t Value, bool IsResolved) {
-                                 bool IsResolved) {
   IsResolved = addReloc(F, Fixup, Target, Value, IsResolved);
   MCFixupKind Kind = Fixup.getKind();
   if (mc::isRelocation(Kind))
@@ -898,15 +897,14 @@ void RISCVAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
   unsigned NumBytes = alignTo(Info.TargetSize + Info.TargetOffset, 8) / 8;
-
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   for (unsigned i = 0; i != NumBytes; ++i) {
-    Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff);
+    Data[i] |= uint8_t((Value >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.h

@@ -46,8 +46,7 @@ public:
   void maybeAddVendorReloc(const MCFragment &, const MCFixup &);
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override;

llvm/lib/Target/SPIRV/MCTargetDesc/SPIRVAsmBackend.cpp

@@ -21,8 +21,7 @@ public:
   SPIRVAsmBackend(llvm::endianness Endian) : MCAsmBackend(Endian) {}
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override {}
-                  bool IsResolved) override {}
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override {

llvm/lib/Target/Sparc/MCTargetDesc/SparcAsmBackend.cpp

@@ -127,8 +127,7 @@ public:
   std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool writeNopData(raw_ostream &OS, uint64_t Count,
                     const MCSubtargetInfo *STI) const override {
@@ -253,21 +252,19 @@ MCFixupKindInfo SparcAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
 }
 
 void SparcAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                 const MCValue &Target,
+                                 const MCValue &Target, uint8_t *Data,
-                                 MutableArrayRef<char> Data, uint64_t Value,
+                                 uint64_t Value, bool IsResolved) {
-                                 bool IsResolved) {
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
   if (!IsResolved)
     return;
   Value = adjustFixupValue(Fixup.getKind(), Value);
 
   unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
-  unsigned Offset = Fixup.getOffset();
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   for (unsigned i = 0; i != NumBytes; ++i) {
     unsigned Idx = Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
-    Data[Offset + Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
+    Data[Idx] |= uint8_t((Value >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp

@@ -113,8 +113,7 @@ public:
   std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
   bool writeNopData(raw_ostream &OS, uint64_t Count,
                     const MCSubtargetInfo *STI) const override;
 };
@@ -152,20 +151,18 @@ MCFixupKindInfo SystemZMCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
 }
 
 void SystemZMCAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                     const MCValue &Target,
+                                     const MCValue &Target, uint8_t *Data,
-                                     MutableArrayRef<char> Data, uint64_t Value,
+                                     uint64_t Value, bool IsResolved) {
-                                     bool IsResolved) {
   if (Target.getSpecifier())
     IsResolved = false;
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
   MCFixupKind Kind = Fixup.getKind();
   if (mc::isRelocation(Kind))
     return;
-  unsigned Offset = Fixup.getOffset();
   unsigned BitSize = getFixupKindInfo(Kind).TargetSize;
   unsigned Size = (BitSize + 7) / 8;
 
-  assert(Offset + Size <= F.getSize() && "Invalid fixup offset!");
+  assert(Fixup.getOffset() + Size <= F.getSize() && "Invalid fixup offset!");
 
   // Big-endian insertion of Size bytes.
   Value = extractBitsForFixup(Kind, Value, Fixup, getContext());
@@ -173,7 +170,7 @@ void SystemZMCAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
     Value &= ((uint64_t)1 << BitSize) - 1;
   unsigned ShiftValue = (Size * 8) - 8;
   for (unsigned I = 0; I != Size; ++I) {
-    Data[Offset + I] |= uint8_t(Value >> ShiftValue);
+    Data[I] |= uint8_t(Value >> ShiftValue);
     ShiftValue -= 8;
   }
 }

llvm/lib/Target/VE/MCTargetDesc/VEAsmBackend.cpp

@@ -112,8 +112,7 @@ public:
   }
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &,
-                  MutableArrayRef<char>, uint64_t Value,
+                  uint8_t *, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool mayNeedRelaxation(unsigned Opcode, ArrayRef<MCOperand> Operands,
                          const MCSubtargetInfo &STI) const override {
@@ -152,7 +151,7 @@ public:
 } // end anonymous namespace
 
 void VEAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                              const MCValue &Target, MutableArrayRef<char> Data,
+                              const MCValue &Target, uint8_t *Data,
                               uint64_t Value, bool IsResolved) {
   switch (Fixup.getKind()) {
   case VE::fixup_ve_tls_gd_hi32:
@@ -173,14 +172,14 @@ void VEAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   Value <<= Info.TargetOffset;
 
   unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
-  unsigned Offset = Fixup.getOffset();
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
   // For each byte of the fragment that the fixup touches, mask in the bits
   // from the fixup value. The Value has been "split up" into the
   // appropriate bitfields above.
   for (unsigned i = 0; i != NumBytes; ++i) {
     unsigned Idx = Endian == llvm::endianness::little ? i : (NumBytes - 1) - i;
-    Data[Offset + Idx] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
+    Data[Idx] |= static_cast<uint8_t>((Value >> (i * 8)) & 0xff);
   }
 }
 

llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyAsmBackend.cpp

@@ -39,7 +39,7 @@ public:
   MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
 
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value, bool) override;
+                  uint8_t *Data, uint64_t Value, bool) override;
 
   std::unique_ptr<MCObjectTargetWriter>
   createObjectTargetWriter() const override;
@@ -80,8 +80,7 @@ bool WebAssemblyAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
 
 void WebAssemblyAsmBackend::applyFixup(const MCFragment &F,
                                        const MCFixup &Fixup,
-                                       const MCValue &Target,
+                                       const MCValue &Target, uint8_t *Data,
-                                       MutableArrayRef<char> Data,
                                        uint64_t Value, bool IsResolved) {
   if (!IsResolved)
     Asm->getWriter().recordRelocation(F, Fixup, Target, Value);
@@ -96,13 +95,13 @@ void WebAssemblyAsmBackend::applyFixup(const MCFragment &F,
   // Shift the value into position.
   Value <<= Info.TargetOffset;
 
-  unsigned Offset = Fixup.getOffset();
+  assert(Fixup.getOffset() + NumBytes <= F.getSize() &&
-  assert(Offset + NumBytes <= F.getSize() && "Invalid fixup offset!");
+         "Invalid fixup offset!");
 
   // For each byte of the fragment that the fixup touches, mask in the
   // bits from the fixup value.
   for (unsigned I = 0; I != NumBytes; ++I)
-    Data[Offset + I] |= uint8_t((Value >> (I * 8)) & 0xff);
+    Data[I] |= uint8_t((Value >> (I * 8)) & 0xff);
 }
 
 std::unique_ptr<MCObjectTargetWriter>

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

@@ -174,8 +174,7 @@ public:
   std::optional<bool> evaluateFixup(const MCFragment &, MCFixup &, MCValue &,
                                     uint64_t &) override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
 
   bool mayNeedRelaxation(unsigned Opcode, ArrayRef<MCOperand> Operands,
                          const MCSubtargetInfo &STI) const override;
@@ -676,9 +675,8 @@ std::optional<bool> X86AsmBackend::evaluateFixup(const MCFragment &,
 }
 
 void X86AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                               const MCValue &Target,
+                               const MCValue &Target, uint8_t *Data,
-                               MutableArrayRef<char> Data, uint64_t Value,
+                               uint64_t Value, bool IsResolved) {
-                               bool IsResolved) {
   // Force relocation when there is a specifier. This might be too conservative
   // - GAS doesn't emit a relocation for call local@plt; local:.
   if (Target.getSpecifier())
@@ -710,7 +708,7 @@ void X86AsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   }
 
   for (unsigned i = 0; i != Size; ++i)
-    Data[Fixup.getOffset() + i] = uint8_t(Value >> (i * 8));
+    Data[i] = uint8_t(Value >> (i * 8));
 }
 
 bool X86AsmBackend::mayNeedRelaxation(unsigned Opcode,

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaAsmBackend.cpp

@@ -37,8 +37,7 @@ public:
   std::optional<bool> evaluateFixup(const MCFragment &, MCFixup &, MCValue &,
                                     uint64_t &) override;
   void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
-                  MutableArrayRef<char> Data, uint64_t Value,
+                  uint8_t *Data, uint64_t Value, bool IsResolved) override;
-                  bool IsResolved) override;
   bool writeNopData(raw_ostream &OS, uint64_t Count,
                     const MCSubtargetInfo *STI) const override;
 
@@ -153,9 +152,8 @@ std::optional<bool> XtensaAsmBackend::evaluateFixup(const MCFragment &F,
 }
 
 void XtensaAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
-                                  const MCValue &Target,
+                                  const MCValue &Target, uint8_t *Data,
-                                  MutableArrayRef<char> Data, uint64_t Value,
+                                  uint64_t Value, bool IsResolved) {
-                                  bool IsResolved) {
   maybeAddReloc(F, Fixup, Target, Value, IsResolved);
   MCContext &Ctx = getContext();
   MCFixupKindInfo Info = getFixupKindInfo(Fixup.getKind());
@@ -168,11 +166,10 @@ void XtensaAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
   if (!Value)
     return; // Doesn't change encoding.
 
-  unsigned Offset = Fixup.getOffset();
   unsigned FullSize = getSize(Fixup.getKind());
 
   for (unsigned i = 0; i != FullSize; ++i) {
-    Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff);
+    Data[i] |= uint8_t((Value >> (i * 8)) & 0xff);
   }
 }