[PATCH] D57376: X86Parser: Fix potential reference to deleted object

[Brandon Jones via Phabricator via llvm-commits]

BrandonTJones created this revision.
BrandonTJones added reviewers: andreadb, grosbach.
Herald added subscribers: llvm-commits, hiraditya.

Within the MatchFPUWaitAlias function, Operands[0] is potentially overwritten leading to &Op referencing a deleted object. To fix this, assign the reference after the function.


Repository:
  rL LLVM

https://reviews.llvm.org/D57376

Files:
  llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp


Index: llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
===================================================================
--- llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -2939,13 +2939,13 @@
                                               uint64_t &ErrorInfo,
                                               bool MatchingInlineAsm) {
   assert(!Operands.empty() && "Unexpect empty operand list!");
-  X86Operand &Op = static_cast<X86Operand &>(*Operands[0]);
   assert(Op.isToken() && "Leading operand should always be a mnemonic!");
   SMRange EmptyRange = None;
 
   // First, handle aliases that expand to multiple instructions.
-  MatchFPUWaitAlias(IDLoc, Op, Operands, Out, MatchingInlineAsm);
-
+  MatchFPUWaitAlias(IDLoc, static_cast<X86Operand &>(*Operands[0]);
+                    , Operands, Out, MatchingInlineAsm);
+  X86Operand &Op = static_cast<X86Operand &>(*Operands[0]);
   bool WasOriginallyInvalidOperand = false;
   unsigned Prefixes = getPrefixes(Operands);
 


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