Add Foreach Loop

Add some data structures to represent for loops.  These will be
referenced during object processing to do any needed iteration and
instantiation.

Add foreach keyword support to the lexer.

Add a mode to indicate that we're parsing a foreach loop.  This allows
the value parser to early-out when processing the foreach value list.

Add a routine to parse foreach iteration declarations.  This is
separate from ParseDeclaration because the type of the named value
(the iterator) doesn't match the type of the initializer value (the
value list).  It also needs to add two values to the foreach record:
the iterator and the value list.

Add parsing support for foreach.

Add the code to process foreach loops and create defs based
on iterator values.

Allow foreach loops to be matched at the top level.

When parsing an IDValue check if it is a foreach loop iterator for one
of the active loops.  If so, return a VarInit for it.

Add Emacs keyword support for foreach.

Add VIM keyword support for foreach.

Add tests to check foreach operation.

Add TableGen documentation for foreach.

Support foreach with multiple objects.

Support non-braced foreach body with one object.

Do not require types for the foreach declaration.  Assume the iterator
type from the iteration list element type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151164 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 222 insertions, 2 deletions

diff --git a/lib/TableGen/TGParser.cpp b/lib/TableGen/TGParser.cpp
index c7cf097aee..04c4fc158f 100644
--- a/lib/TableGen/TGParser.cpp
+++ b/lib/TableGen/TGParser.cpp
@@ -289,6 +289,113 @@ bool TGParser::AddSubMultiClass(MultiClass *CurMC,
   return false;
 }
 
+/// ProcessForeachDefs - Given a record, apply all of the variable
+/// values in all surrounding foreach loops, creating new records for
+/// each combination of values.
+bool TGParser::ProcessForeachDefs(Record *CurRec, MultiClass *CurMultiClass,
+                                  SMLoc Loc) {
+  // We want to instantiate a new copy of CurRec for each combination
+  // of nested loop iterator values.  We don't want top instantiate
+  // any copies until we have values for each loop iterator.
+  IterSet IterVals;
+  for (LoopVector::iterator Loop = Loops.begin(), LoopEnd = Loops.end();
+       Loop != LoopEnd;
+       ++Loop) {
+    // Process this loop.
+    if (ProcessForeachDefs(CurRec, CurMultiClass, Loc,
+                           IterVals, *Loop, Loop+1)) {
+      Error(Loc,
+            "Could not process loops for def " + CurRec->getNameInitAsString());
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/// ProcessForeachDefs - Given a record, a loop and a loop iterator,
+/// apply each of the variable values in this loop and then process
+/// subloops.
+bool TGParser::ProcessForeachDefs(Record *CurRec, MultiClass *CurMultiClass,
+                                  SMLoc Loc, IterSet &IterVals,
+                                  ForeachLoop &CurLoop,
+                                  LoopVector::iterator NextLoop) {
+  Init *IterVar = CurLoop.IterVar;
+  ListInit *List = dynamic_cast<ListInit *>(CurLoop.ListValue);
+
+  if (List == 0) {
+    Error(Loc, "Loop list is not a list");
+    return true;
+  }
+
+  // Process each value.
+  for (int64_t i = 0; i < List->getSize(); ++i) {
+    Init *ItemVal = List->resolveListElementReference(*CurRec, 0, i);
+    IterVals.push_back(IterRecord(IterVar, ItemVal));
+
+    if (IterVals.size() == Loops.size()) {
+      // Ok, we have all of the iterator values for this point in the
+      // iteration space.  Instantiate a new record to reflect this
+      // combination of values.
+      Record *IterRec = new Record(*CurRec);
+
+      // Set the iterator values now.
+      for (IterSet::iterator i = IterVals.begin(), iend = IterVals.end();
+           i != iend;
+           ++i) {
+        VarInit *IterVar = dynamic_cast<VarInit *>(i->IterVar);
+        if (IterVar == 0) {
+          Error(Loc, "foreach iterator is unresolved");
+          return true;
+        }
+
+        TypedInit *IVal  = dynamic_cast<TypedInit *>(i->IterValue);
+        if (IVal == 0) {
+          Error(Loc, "foreach iterator value is untyped");
+          return true;
+        }
+
+        IterRec->addValue(RecordVal(IterVar->getName(), IVal->getType(), false));
+
+        if (SetValue(IterRec, Loc, IterVar->getName(),
+                     std::vector<unsigned>(), IVal)) {
+          Error(Loc, "when instantiating this def");
+          return true;
+        }
+
+        // Resolve it next.
+        IterRec->resolveReferencesTo(IterRec->getValue(IterVar->getName()));
+
+        // Remove it.
+        IterRec->removeValue(IterVar->getName());
+      }
+
+      if (Records.getDef(IterRec->getNameInitAsString())) {
+        Error(Loc, "def already exists: " + IterRec->getNameInitAsString());
+        return true;
+      }
+
+      Records.addDef(IterRec);
+      IterRec->resolveReferences();
+    }
+
+    if (NextLoop != Loops.end()) {
+      // Process nested loops.
+      if (ProcessForeachDefs(CurRec, CurMultiClass, Loc, IterVals, *NextLoop,
+                             NextLoop+1)) {
+        Error(Loc,
+              "Could not process loops for def " +
+              CurRec->getNameInitAsString());
+        return true;
+      }
+    }
+
+    // We're done with this iterator.
+    IterVals.pop_back();
+  }
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // Parser Code
 //===----------------------------------------------------------------------===//
@@ -296,7 +403,8 @@ bool TGParser::AddSubMultiClass(MultiClass *CurMC,
 /// isObjectStart - Return true if this is a valid first token for an Object.
 static bool isObjectStart(tgtok::TokKind K) {
   return K == tgtok::Class || K == tgtok::Def ||
-         K == tgtok::Defm || K == tgtok::Let || K == tgtok::MultiClass;
+         K == tgtok::Defm || K == tgtok::Let ||
+         K == tgtok::MultiClass || K == tgtok::Foreach;
 }
 
 static std::string GetNewAnonymousName() {
@@ -698,6 +806,15 @@ Init *TGParser::ParseIDValue(Record *CurRec,
     }
   }
 
+  // If this is in a foreach loop, make sure it's not a loop iterator
+  for (LoopVector::iterator i = Loops.begin(), iend = Loops.end();
+       i != iend;
+       ++i) {
+    VarInit *IterVar = dynamic_cast<VarInit *>(i->IterVar);
+    if (IterVar && IterVar->getName() == Name)
+      return IterVar;
+  }
+
   if (Mode == ParseNameMode)
     return StringInit::get(Name);
 
@@ -1353,7 +1470,7 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
     switch (Lex.getCode()) {
     default: return Result;
     case tgtok::l_brace: {
-      if (Mode == ParseNameMode)
+      if (Mode == ParseNameMode || Mode == ParseForeachMode)
         // This is the beginning of the object body.
         return Result;
 
@@ -1605,6 +1722,50 @@ Init *TGParser::ParseDeclaration(Record *CurRec,
   return DeclName;
 }
 
+/// ParseForeachDeclaration - Read a foreach declaration, returning
+/// the name of the declared object or a NULL Init on error.  Return
+/// the name of the parsed initializer list through ForeachListName.
+///
+///  ForeachDeclaration ::= ID '=' Value
+///
+Init *TGParser::ParseForeachDeclaration(Init *&ForeachListValue) {
+  if (Lex.getCode() != tgtok::Id) {
+    TokError("Expected identifier in foreach declaration");
+    return 0;
+  }
+
+  Init *DeclName = StringInit::get(Lex.getCurStrVal());
+  Lex.Lex();
+
+  // If a value is present, parse it.
+  if (Lex.getCode() != tgtok::equal) {
+    TokError("Expected '=' in foreach declaration");
+    return 0;
+  }
+  Lex.Lex();  // Eat the '='
+
+  // Expect a list initializer.
+  ForeachListValue = ParseValue(0, 0, ParseForeachMode);
+
+  TypedInit *TypedList = dynamic_cast<TypedInit *>(ForeachListValue);
+  if (TypedList == 0) {
+    TokError("Value list is untyped");
+    return 0;
+  }
+
+  RecTy *ValueType = TypedList->getType();
+  ListRecTy *ListType = dynamic_cast<ListRecTy *>(ValueType);
+  if (ListType == 0) {
+    TokError("Value list is not of list type");
+    return 0;
+  }
+
+  RecTy *IterType = ListType->getElementType();
+  VarInit *IterVar = VarInit::get(DeclName, IterType);
+
+  return IterVar;
+}
+
 /// ParseTemplateArgList - Read a template argument list, which is a non-empty
 /// sequence of template-declarations in <>'s.  If CurRec is non-null, these are
 /// template args for a def, which may or may not be in a multiclass.  If null,
@@ -1817,6 +1978,63 @@ bool TGParser::ParseDef(MultiClass *CurMultiClass) {
     }
   }
 
+  if (ProcessForeachDefs(CurRec, CurMultiClass, DefLoc)) {
+    Error(DefLoc,
+          "Could not process loops for def" + CurRec->getNameInitAsString());
+    return true;
+  }
+
+  return false;
+}
+
+/// ParseForeach - Parse a for statement.  Return the record corresponding
+/// to it.  This returns true on error.
+///
+///   Foreach ::= FOREACH Declaration IN '{ ObjectList '}'
+///   Foreach ::= FOREACH Declaration IN Object
+///
+bool TGParser::ParseForeach(MultiClass *CurMultiClass) {
+  assert(Lex.getCode() == tgtok::Foreach && "Unknown tok");
+  Lex.Lex();  // Eat the 'for' token.
+
+  // Make a temporary object to record items associated with the for
+  // loop.
+  Init *ListValue = 0;
+  Init *IterName = ParseForeachDeclaration(ListValue);
+  if (IterName == 0)
+    return TokError("expected declaration in for");
+
+  if (Lex.getCode() != tgtok::In)
+    return TokError("Unknown tok");
+  Lex.Lex();  // Eat the in
+
+  // Create a loop object and remember it.
+  Loops.push_back(ForeachLoop(IterName, ListValue));
+
+  if (Lex.getCode() != tgtok::l_brace) {
+    // FOREACH Declaration IN Object
+    if (ParseObject(CurMultiClass))
+      return true;
+  }
+  else {
+    SMLoc BraceLoc = Lex.getLoc();
+    // Otherwise, this is a group foreach.
+    Lex.Lex();  // eat the '{'.
+
+    // Parse the object list.
+    if (ParseObjectList(CurMultiClass))
+      return true;
+
+    if (Lex.getCode() != tgtok::r_brace) {
+      TokError("expected '}' at end of foreach command");
+      return Error(BraceLoc, "to match this '{'");
+    }
+    Lex.Lex();  // Eat the }
+  }
+
+  // We've processed everything in this loop.
+  Loops.pop_back();
+
   return false;
 }
 
@@ -2010,6 +2228,7 @@ bool TGParser::ParseMultiClass() {
         case tgtok::Let:
         case tgtok::Def:
         case tgtok::Defm:
+        case tgtok::Foreach:
           if (ParseObject(CurMultiClass))
             return true;
          break;
@@ -2305,6 +2524,7 @@ bool TGParser::ParseObject(MultiClass *MC) {
     return TokError("Expected class, def, defm, multiclass or let definition");
   case tgtok::Let:   return ParseTopLevelLet(MC);
   case tgtok::Def:   return ParseDef(MC);
+  case tgtok::Foreach:   return ParseForeach(MC);
   case tgtok::Defm:  return ParseDefm(MC);
   case tgtok::Class: return ParseClass();
   case tgtok::MultiClass: return ParseMultiClass();