[TableGen] Enhance !cast<string> to handle bit and bits types

[Paul-C-Anagnostopoulos]

Summary

This revision enhances the !cast operator so it can cast bit and bits to string. It could already cast int to string.

I added a test for this change.

Note that allowing !cast to handle bit and bits means that the paste operator (#) can concatenate them.

[fpichet]

This works for me

[madhur13490]

llvm/test/TableGen/cast-string.td

42

Would it be useful if we can cast bits to the literal string also and not just to its decimal equivalent? e.g. something like

!cast<stringref>(bits1) -> "0b0101".

I am not sure if this exists today or any backend needs it.

54

Typo - Initializer?

[Paul-C-Anagnostopoulos]

llvm/test/TableGen/cast-string.td

42

It can't be a pseudo-type without all sorts of horrible parsing hackery. I'll look around to see if it seems useful and then add a !binaryliteral operator if so.

54

I left off the "I" so it won't matter whether it is upper- or lowercase.

llvm/lib/TableGen/Record.cpp

Init *UnOpInit::Fold(Record *CurRec, bool IsFinal) const {
   case CAST:
     if (isa<StringRecTy>(getType())) {
       if (StringInit *LHSs = dyn_cast<StringInit>(LHS))
         return LHSs;
 
       if (DefInit *LHSd = dyn_cast<DefInit>(LHS))
         return StringInit::get(LHSd->getAsString());
 
-      if (IntInit *LHSi = dyn_cast<IntInit>(LHS))
+      if (IntInit *LHSi =
+              dyn_cast_or_null<IntInit>(LHS->convertInitializerTo(IntRecTy::get())))
         return StringInit::get(LHSi->getAsString());
+
     } else if (isa<RecordRecTy>(getType())) {
       if (StringInit *Name = dyn_cast<StringInit>(LHS)) {
         if (!CurRec && !IsFinal)
           break;
         assert(CurRec && "NULL pointer");
         Record *D;
 
         // Self-references are allowed, but their resolution is delayed until

llvm/test/TableGen/cast-string.td

+// RUN: llvm-tblgen %s | FileCheck %s
+// RUN: not llvm-tblgen -DERROR1 %s 2>&1 | FileCheck --check-prefix=ERROR1 %s
+
+// This file tests the !cast bang operator with the result type string.
+
+defvar IntList = [0, 1, 2, 3, 4, 5, 6];
+
+// CHECK: def Rec0
+// CHECK:   string str3 = "a string here"
+
+def Rec0 {
+  string str = "a string";
+  string str2 = !cast<string>(str);
+  string str3 = !cast<string>(str # " here");
+}
+
+// CHECK: def Rec1
+// CHECK:   string str = "42 -108"
+
+def Rec1 {
+  int int1 = 42;
+  int int2 = -108;
+  string str = !cast<string>(int1) # " " # !cast<string>(int2);
+}
+
+// CHECK: def Rec2
+// CHECK:   string str = "0, 1"
+
+def Rec2 {
+  bit bit1 = false;
+  bit bit2 = true;
+  string str = !cast<string>(bit1) # ", " # !cast<string>(bit2);
+}
+
+// CHECK: def Rec3
+// CHECK:   string str = "5 and 37"
+
+def Rec3 {
+  bits<4> bits1 = 0b0101;
+  bits<8> bits2 = 0b00100101;
+  string str = !cast<string>(bits1) # " and " # !cast<string>(bits2);
+}
+
+// CHECK: def Rec4
+// CHECK:   string str = "Rec1, Rec2"
+
+def Rec4 {
+  string str = !cast<string>(Rec1) # ", " # !cast<string>(Rec2);
+}
+
+#ifdef ERROR1
+
+// ERROR1: nitializer of 'str' in 'Rec5' could not be fully resolved
+
+def Rec5 {
+  string str = !cast<string>(IntList);
+}
+
+#endif