[lld] [LLD] Fix crash on parsing ':ALIGN' in linker script (PR #146723)

[Fangrui Song via llvm-commits]

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@@ -1229,6 +1229,9 @@ SymbolAssignment *ScriptParser::readSymbolAssignment(StringRef name) {
 // This is an operator-precedence parser to parse a linker
 // script expression.
 Expr ScriptParser::readExpr() {
+  // Do not try to read expression if an error has already been encountered.
+  if (atEOF())
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MaskRay wrote:

This looks ok to me as well. A few parser functions call `atEOF()` at the beginning, when they expect to consume at least one token.

https://github.com/llvm/llvm-project/pull/146723