Add initial support for list slices. This currently allows you to do stuff

like this:

def B {
  list<int> X = [10, 20, 30, 4, 1, 1231, 20] [2-4,2,2,0-6];
}

... which isn't particularly useful, but more is to come.

llvm-svn: 15247

llvm/utils/TableGen/FileParser.y

@@ -300,6 +300,14 @@ Value : INTVAL {
     }
     $$ = new DagInit(D, *$3);
     delete $2; delete $3;
+  } | Value '[' BitList ']' {
+    std::reverse($3->begin(), $3->end());
+    $$ = $1->convertInitListSlice(*$3);
+    if ($$ == 0) {
+      err() << "Invalid list slice for value '" << *$1 << "'!\n";
+      exit(1);
+    }
+    delete $3;
   };
 
 OptVarName : /* empty */ {
@@ -330,41 +338,61 @@ RBitList : INTVAL {
     $$ = new std::vector<unsigned>();
     $$->push_back($1);
   } | INTVAL '-' INTVAL {
-    if ($1 < $3 || $1 < 0 || $3 < 0) {
-      err() << "Invalid bit range: " << $1 << "-" << $3 << "!\n";
+    if ($1 < 0 || $3 < 0) {
+      err() << "Invalid range: " << $1 << "-" << $3 << "!\n";
       exit(1);
     }
     $$ = new std::vector<unsigned>();
-    for (int i = $1; i >= $3; --i)
-      $$->push_back(i);
+    if ($1 < $3) {
+      for (int i = $1; i <= $3; ++i)
+        $$->push_back(i);
+    } else {
+      for (int i = $1; i >= $3; --i)
+        $$->push_back(i);
+    }
   } | INTVAL INTVAL {
     $2 = -$2;
-    if ($1 < $2 || $1 < 0 || $2 < 0) {
-      err() << "Invalid bit range: " << $1 << "-" << $2 << "!\n";
+    if ($1 < 0 || $2 < 0) {
+      err() << "Invalid range: " << $1 << "-" << $2 << "!\n";
       exit(1);
     }
     $$ = new std::vector<unsigned>();
-    for (int i = $1; i >= $2; --i)
-      $$->push_back(i);
+    if ($1 < $2) {
+      for (int i = $1; i <= $2; ++i)
+        $$->push_back(i);
+    } else {
+      for (int i = $1; i >= $2; --i)
+        $$->push_back(i);
+    }
   } | RBitList ',' INTVAL {
     ($$=$1)->push_back($3);
   } | RBitList ',' INTVAL '-' INTVAL {
-    if ($3 < $5 || $3 < 0 || $5 < 0) {
-      err() << "Invalid bit range: " << $3 << "-" << $5 << "!\n";
+    if ($3 < 0 || $5 < 0) {
+      err() << "Invalid range: " << $3 << "-" << $5 << "!\n";
       exit(1);
     }
     $$ = $1;
-    for (int i = $3; i >= $5; --i)
-      $$->push_back(i);
+    if ($3 < $5) {
+      for (int i = $3; i <= $5; ++i)
+        $$->push_back(i);
+    } else {
+      for (int i = $3; i >= $5; --i)
+        $$->push_back(i);
+    }
   } | RBitList ',' INTVAL INTVAL {
     $4 = -$4;
-    if ($3 < $4 || $3 < 0 || $4 < 0) {
-      err() << "Invalid bit range: " << $3 << "-" << $4 << "!\n";
+    if ($3 < 0 || $4 < 0) {
+      err() << "Invalid range: " << $3 << "-" << $4 << "!\n";
       exit(1);
     }
     $$ = $1;
-    for (int i = $3; i >= $4; --i)
-      $$->push_back(i);
+    if ($3 < $4) {
+      for (int i = $3; i <= $4; ++i)
+        $$->push_back(i);
+    } else {
+      for (int i = $3; i >= $4; --i)
+        $$->push_back(i);
+    }
   };
 
 BitList : RBitList { $$ = $1; std::reverse($1->begin(), $1->end()); };

llvm/utils/TableGen/Record.cpp

@@ -310,6 +310,16 @@ Init *IntInit::convertInitializerBitRange(const std::vector<unsigned> &Bits) {
   return BI;
 }
 
+Init *ListInit::convertInitListSlice(const std::vector<unsigned> &Elements) {
+  std::vector<Init*> Vals;
+  for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
+    if (Elements[i] >= getSize())
+      return 0;
+    Vals.push_back(getElement(Elements[i]));
+  }
+  return new ListInit(Vals);
+}
+
 void ListInit::print(std::ostream &OS) const {
   OS << "[";
   for (unsigned i = 0, e = Values.size(); i != e; ++i) {

llvm/utils/TableGen/Record.h

@@ -304,6 +304,15 @@ struct Init {
     return 0;
   }
 
+  /// convertInitListSlice - This method is used to implement the list slice
+  /// selection operator.  Given an initializer, it selects the specified list
+  /// elements, returning them as a new init of list type.  If it is not legal
+  /// to take a slice of this, return null.
+  ///
+  virtual Init *convertInitListSlice(const std::vector<unsigned> &Elements) {
+    return 0;
+  }
+
   /// getFieldType - This method is used to implement the FieldInit class.
   /// Implementors of this method should return the type of the named field if
   /// they are of record type.
@@ -466,6 +475,8 @@ public:
     return Values[i];
   }
 
+  Init *convertInitListSlice(const std::vector<unsigned> &Elements);
+
   virtual Init *convertInitializerTo(RecTy *Ty) {
     return Ty->convertValue(this);
   }