[TableGen] Fix instantiating multiclass in foreach

[jyyou.tw]

Summary

If multiclass argument comes from loop varaible and argument is
record type, it will not recognize the type.

This patch ensures that loop variables are resolved correctly.

[Paul-C-Anagnostopoulos]

I presume this change passes all the TableGen, mlir, and clang tests?

llvm/lib/TableGen/TGParser.cpp

3528

Is there a reason why we shouldn't use !CurMultiClass?

llvm/test/TableGen/foreach-multiclass.td

123 ↗

(On Diff #318817)

Could you add a comment explaining what this is testing, since it is relatively obscure?

[jyyou.tw]

Refine test case

[jyyou.tw]

In D95308#2518218, @Paul-C-Anagnostopoulos wrote:

I presume this change passes all the TableGen, mlir, and clang tests?

Yes, tests are passed.

llvm/lib/TableGen/TGParser.cpp

3528

If defm is placed in foreach and multiclass has foreach, the parsing flow is

parse foreach -> parse defm -> resolve multiclass entries -> resolve foreach of multiclass

In this case, !CurMultiClass is not enough. When resolving foreach of multiclass, Loop.ListValue is resolved as FieldInit only.
It must be further resolved, so I add Loops.empty() to ensure that.

[Paul-C-Anagnostopoulos]

llvm/lib/TableGen/TGParser.cpp

3528

Sorry, I didn't mean just !CurMultiClass. I meant:

!CurMultiClass && Loops.empty()

[jyyou.tw]

Refine condition

[jyyou.tw]

Missing test

[Paul-C-Anagnostopoulos]

Looks good to me.

[jyyou.tw]

If this patch is OK, could someone please commit it? I don't have commit access.

[Paul-C-Anagnostopoulos]

Okay, let me do this one first. I've never committed for someone else, so something might go wrong.

[Paul-C-Anagnostopoulos]

This revision is pushed.

llvm/lib/TableGen/TGParser.cpp

for (unsigned i = 0, e = TArgs.size(); i != e; ++i) {
                            "'");
         }
         Substs.emplace_back(TArgs[i], Default);
       }
     }
 
     Substs.emplace_back(QualifiedNameOfImplicitName(MC), DefmName);
 
-    if (resolve(MC->Entries, Substs, CurMultiClass == nullptr && Loops.empty(),
+    if (resolve(MC->Entries, Substs, !CurMultiClass && Loops.empty(),
                 &NewEntries, &SubClassLoc))
       return true;
 
     if (!consume(tgtok::comma))
       break;
 
     if (Lex.getCode() != tgtok::Id)
       return TokError("expected identifier");