[TableGen] Add a !listremove() bang operator

This patch proposes to add a !listremove() bang operator to allow us to prune list entries by removing any entries from the first list arg that are also contained in the second list arg.

The particular use case I have in mind is for improved analysis of x86 scheduler models for which I'm hoping to start using the CodeGenProcModel 'Unsupported' features lists, which lists the ISA features a particular model DOESN'T support - with such a diverse and growing list of x86 ISAs, I don't want to have to update all these lists with every ISA change to every model - so I'm intending to keep a single central list of all x86 features, and then have the each model "remove" the features that it supports via a !listremove() - leaving just the unsupported ones.

Differential Revision: https://reviews.llvm.org/D139642

1 files changed, 19 insertions, 1 deletions

diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index ed20ffd..7fc46a8 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -1179,6 +1179,7 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
   case tgtok::XGt:
   case tgtok::XListConcat:
   case tgtok::XListSplat:
+  case tgtok::XListRemove:
   case tgtok::XStrConcat:
   case tgtok::XInterleave:
   case tgtok::XSetDagOp: { // Value ::= !binop '(' Value ',' Value ')'
@@ -1208,6 +1209,7 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     case tgtok::XGt:     Code = BinOpInit::GT; break;
     case tgtok::XListConcat: Code = BinOpInit::LISTCONCAT; break;
     case tgtok::XListSplat:  Code = BinOpInit::LISTSPLAT; break;
+    case tgtok::XListRemove: Code = BinOpInit::LISTREMOVE; break;
     case tgtok::XStrConcat:  Code = BinOpInit::STRCONCAT; break;
     case tgtok::XInterleave: Code = BinOpInit::INTERLEAVE; break;
     case tgtok::XSetDagOp:   Code = BinOpInit::SETDAGOP; break;
@@ -1246,12 +1248,16 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
       // ArgType for the comparison operators is not yet known.
       break;
     case tgtok::XListConcat:
-      // We don't know the list type until we parse the first argument
+      // We don't know the list type until we parse the first argument.
       ArgType = ItemType;
       break;
     case tgtok::XListSplat:
       // Can't do any typechecking until we parse the first argument.
       break;
+    case tgtok::XListRemove:
+      // We don't know the list type until we parse the first argument.
+      ArgType = ItemType;
+      break;
     case tgtok::XStrConcat:
       Type = StringRecTy::get(Records);
       ArgType = StringRecTy::get(Records);
@@ -1329,6 +1335,13 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
           }
           ArgType = nullptr; // Broken invariant: types not identical.
           break;
+        case BinOpInit::LISTREMOVE:
+          if (!isa<ListRecTy>(ArgType)) {
+            Error(InitLoc, Twine("expected a list, got value of type '") +
+                               ArgType->getAsString() + "'");
+            return nullptr;
+          }
+          break;
         case BinOpInit::EQ:
         case BinOpInit::NE:
           if (!ArgType->typeIsConvertibleTo(IntRecTy::get(Records)) &&
@@ -1423,6 +1436,9 @@ Init *TGParser::ParseOperation(Record *CurRec, RecTy *ItemType) {
     // listsplat returns a list of type of the *first* argument.
     if (Code == BinOpInit::LISTSPLAT)
       Type = cast<TypedInit>(InitList.front())->getType()->getListTy();
+    // listremove returns a list with type of the argument.
+    if (Code == BinOpInit::LISTREMOVE)
+      Type = ArgType;
 
     // We allow multiple operands to associative operators like !strconcat as
     // shorthand for nesting them.
@@ -2154,6 +2170,7 @@ Init *TGParser::ParseOperationCond(Record *CurRec, RecTy *ItemType) {
 ///   SimpleValue ::= SRLTOK '(' Value ',' Value ')'
 ///   SimpleValue ::= LISTCONCATTOK '(' Value ',' Value ')'
 ///   SimpleValue ::= LISTSPLATTOK '(' Value ',' Value ')'
+///   SimpleValue ::= LISTREMOVETOK '(' Value ',' Value ')'
 ///   SimpleValue ::= STRCONCATTOK '(' Value ',' Value ')'
 ///   SimpleValue ::= COND '(' [Value ':' Value,]+ ')'
 ///
@@ -2453,6 +2470,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
   case tgtok::XGt:
   case tgtok::XListConcat:
   case tgtok::XListSplat:
+  case tgtok::XListRemove:
   case tgtok::XStrConcat:
   case tgtok::XInterleave:
   case tgtok::XSetDagOp: // Value ::= !binop '(' Value ',' Value ')'