[ms] [llvm-ml] Allow use of locally-defined variables in expressions

[epastor]

Summary

MASM allows variables defined by equate statements to be used in expressions.

[epastor]

Sync to HEAD

[thakis]

llvm/test/tools/llvm-ml/variable.test

10

add a CHECK-NOT: .byte 0 here to check that it's exactly 3

[epastor]

Check that the expression is exactly 3, not just >= 3.

[epastor]

Rebase to HEAD

llvm/lib/MC/MCParser/MasmParser.cpp

bool MasmParser::parseDirectiveEquate(StringRef IDVal, StringRef Name,
   if (DirKind == DK_TEXTEQU)
     return TokError("expected <text> in '" + Twine(IDVal) + "' directive");
 
   // Parse as expression assignment.
   const MCExpr *Expr;
   SMLoc EndLoc, StartLoc = Lexer.getLoc();
   if (parseExpression(Expr, EndLoc))
     return addErrorSuffix(" in '" + Twine(IDVal) + "' directive");
+  MCSymbol *Sym = getContext().getOrCreateSymbol(Var.Name);
+  Sym->setRedefinable(Var.Redefinable);
+  Sym->setVariableValue(Expr);
+  Sym->setExternal(false);
+
   if (Expr->evaluateAsAbsolute(Var.NumericValue,
                                getStreamer().getAssemblerPtr()))
     return false;
 
   // Not an absolute expression; define as a text replacement.
   Var.IsText = true;
   Var.TextValue = StringRef(StartLoc.getPointer(),
                             EndLoc.getPointer() - StartLoc.getPointer()).str();

llvm/test/tools/llvm-ml/variable.test

+# RUN: llvm-ml -filetype=asm %s | FileCheck %s
+
+.data
+t1_value equ 1 or 2
+
+t1 BYTE t1_value DUP (0)
+; CHECK: t1:
+; CHECK-NEXT: .byte 0
+; CHECK-NEXT: .byte 0
+; CHECK-NEXT: .byte 0
+
+END