[TableGen] Fix a potential crash when operand doesn't appear in the instruction pattern

shiltian · shiltian · commit 85ff6d6a2970 · 2024-04-04T15:54:45.000-04:00
We have a check of whether an operand is in the instruction pattern, and emit an
error if it is not, but we simply continue execution, including directly
dereferencing a point-like object `InVal`, which will be just created when
accessing the map. It contains a `nullptr` so dereferencing it causes crash.
This is a very trivial fix.
diff --git a/llvm/utils/TableGen/Common/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/Common/CodeGenDAGPatterns.cpp
@@ -3872,6 +3872,7 @@ void CodeGenDAGPatterns::parseInstructionPattern(CodeGenInstruction &CGI,
       }
       I.error("Operand $" + OpName +
               " does not appear in the instruction pattern");
+      continue;
     }
     TreePatternNodePtr InVal = InstInputs[OpName];
     InstInputs.erase(OpName); // It occurred, remove from map.

Original file line number	Diff line number	Diff line change
`@@ -3872,6 +3872,7 @@ void CodeGenDAGPatterns::parseInstructionPattern(CodeGenInstruction &CGI,`
`3872`	`3872`	`}`
`3873`	`3873`	`I.error("Operand $" + OpName +`
`3874`	`3874`	`" does not appear in the instruction pattern");`
	`3875`	`+ continue;`
`3875`	`3876`	`}`
`3876`	`3877`	`TreePatternNodePtr InVal = InstInputs[OpName];`
`3877`	`3878`	`InstInputs.erase(OpName); // It occurred, remove from map.`