[llvm] Initialize and move UseUpRegs outside of `union` MemOp struct.

[pifon2a]

Summary

Asan complained about uninitialized bool

invalid-bool-load
llvm/lib/Target/X86/AsmParser/X86Operand.h:389:12: runtime error: load
of value 171, which is not a valid value for type 'bool'

[bkramer]

I think this is fine.

[xiangzhangllvm]

First thanks very much for this patch!

I didn't understand why Buildbot fail on clang/test/CodeGen/ms-inline-asm.c on sanitizer-x86_64-linux-bootstrap-ubsan

This test passed in my local machine (before/without this patch).
$../build-all/bin/llvm-lit clang/test/CodeGen/ms-inline-asm.c
-- Testing: 1 tests, 1 workers --
PASS: Clang :: CodeGen/ms-inline-asm.c (1 of 1)

Testing Time: 0.51s
  Passed: 1

[skan]

LGTM, thanks!

[pengfei]

In D122405#3406886, @xiangzhangllvm wrote:

First thanks very much for this patch!

I didn't understand why Buildbot fail on clang/test/CodeGen/ms-inline-asm.c on sanitizer-x86_64-linux-bootstrap-ubsan

This test passed in my local machine (before/without this patch).
$../build-all/bin/llvm-lit clang/test/CodeGen/ms-inline-asm.c
-- Testing: 1 tests, 1 workers --
PASS: Clang :: CodeGen/ms-inline-asm.c (1 of 1)

Testing Time: 0.51s
  Passed: 1

Not sure if you need to run asan check mannually. Here are config for sanitizer-x86_64-linux-bootstrap-ubsan: https://github.com/llvm/llvm-zorg/blob/main/zorg/buildbot/builders/sanitizers/buildbot_cmake.sh

[xiangzhangllvm]

In D122405#3407108, @pengfei wrote:

Not sure if you need to run asan check mannually. Here are config for sanitizer-x86_64-linux-bootstrap-ubsan: https://github.com/llvm/llvm-zorg/blob/main/zorg/buildbot/builders/sanitizers/buildbot_cmake.sh

Thanks for reminding! I think this must be compiler-rt use X86Operand code problem. Any way, these has be fixed by pifon2a. There is no logic changes, Let it be : )

[MaskRay]

Asan complained about uninitialized bool

It's not "uninitialized" :) It's a value outside of {0, 1}.

llvm/lib/Target/X86/AsmParser/X86Operand.h

struct X86Operand final : public MCParsedAsmOperand {
   enum KindTy { Token, Register, Immediate, Memory, Prefix, DXRegister } Kind;
 
   SMLoc StartLoc, EndLoc;
   SMLoc OffsetOfLoc;
   StringRef SymName;
   void *OpDecl;
   bool AddressOf;
 
+  /// This used for inline asm which may specify base reg and index reg for
+  /// MemOp. e.g. ARR[eax + ecx*4], so no extra reg can be used for MemOp.
+  bool UseUpRegs = false;
+
   struct TokOp {
     const char *Data;
     unsigned Length;
   };
 
   struct RegOp {
     unsigned RegNo;
   };
struct MemOp {
     unsigned IndexReg;
     unsigned Scale;
     unsigned Size;
     unsigned ModeSize;
 
     /// If the memory operand is unsized and there are multiple instruction
     /// matches, prefer the one with this size.
     unsigned FrontendSize;
-
-    /// This used for inline asm which may specify base reg and index reg for
-    /// MemOp. e.g. ARR[eax + ecx*4], so no extra reg can be used for MemOp.
-    bool UseUpRegs;
   };
 
   union {
     struct TokOp Tok;
     struct RegOp Reg;
     struct ImmOp Imm;
     struct MemOp Mem;
     struct PrefOp Pref;
struct X86Operand final : public MCParsedAsmOperand {
   bool isAVX512RC() const{
       return isImm();
   }
 
   bool isAbsMem16() const {
     return isAbsMem() && Mem.ModeSize == 16;
   }
 
-  bool isMemUseUpRegs() const override {
-    return Mem.UseUpRegs;
-  }
+  bool isMemUseUpRegs() const override { return UseUpRegs; }
 
   bool isSrcIdx() const {
     return !getMemIndexReg() && getMemScale() == 1 &&
       (getMemBaseReg() == X86::RSI || getMemBaseReg() == X86::ESI ||
        getMemBaseReg() == X86::SI) && isa<MCConstantExpr>(getMemDisp()) &&
       cast<MCConstantExpr>(getMemDisp())->getValue() == 0;
   }
   bool isSrcIdx8() const {
CreateMem(unsigned ModeSize, const MCExpr *Disp, SMLoc StartLoc, SMLoc EndLoc,
     Res->Mem.Disp     = Disp;
     Res->Mem.BaseReg  = 0;
     Res->Mem.DefaultBaseReg = 0;
     Res->Mem.IndexReg = 0;
     Res->Mem.Scale    = 1;
     Res->Mem.Size     = Size;
     Res->Mem.ModeSize = ModeSize;
     Res->Mem.FrontendSize = FrontendSize;
-    Res->Mem.UseUpRegs = UseUpRegs;
+    Res->UseUpRegs = UseUpRegs;
     Res->SymName      = SymName;
     Res->OpDecl       = OpDecl;
     Res->AddressOf    = false;
     return Res;
   }
 
   /// Create a generalized memory operand.
   static std::unique_ptr<X86Operand>
CreateMem(unsigned ModeSize, unsigned SegReg, const MCExpr *Disp,
     Res->Mem.Disp     = Disp;
     Res->Mem.BaseReg  = BaseReg;
     Res->Mem.DefaultBaseReg = DefaultBaseReg;
     Res->Mem.IndexReg = IndexReg;
     Res->Mem.Scale    = Scale;
     Res->Mem.Size     = Size;
     Res->Mem.ModeSize = ModeSize;
     Res->Mem.FrontendSize = FrontendSize;
-    Res->Mem.UseUpRegs = UseUpRegs;
+    Res->UseUpRegs = UseUpRegs;
     Res->SymName      = SymName;
     Res->OpDecl       = OpDecl;
     Res->AddressOf    = false;
     return Res;
   }
 };
 
 } // end namespace llvm
 
 #endif // LLVM_LIB_TARGET_X86_ASMPARSER_X86OPERAND_H