From cebb4ee93a0064e4a2cb1fd1da7455b01e5655cb Mon Sep 17 00:00:00 2001
From: David Greene <greened@obbligato.org>
Date: Wed, 22 Feb 2012 16:09:41 +0000
Subject: 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
---
 lib/TableGen/TGParser.h | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

(limited to 'lib/TableGen/TGParser.h')

diff --git a/lib/TableGen/TGParser.h b/lib/TableGen/TGParser.h
index 54cd99a8a4..509b02c078 100644
--- a/lib/TableGen/TGParser.h
+++ b/lib/TableGen/TGParser.h
@@ -42,11 +42,25 @@ namespace llvm {
     }
   };
   
+  /// ForeachLoop - Record the iteration state associated with a for loop.
+  /// This is used to instantiate items in the loop body.
+  struct ForeachLoop {
+    Init *IterVar;
+    Init *ListValue;
+
+    ForeachLoop(Init *IVar, Init *LValue) : IterVar(IVar), ListValue(LValue) {};
+  };
+
 class TGParser {
   TGLexer Lex;
   std::vector<std::vector<LetRecord> > LetStack;
   std::map<std::string, MultiClass*> MultiClasses;
   
+  /// Loops - Keep track of any foreach loops we are within.
+  ///
+  typedef std::vector<ForeachLoop> LoopVector;
+  LoopVector Loops;
+
   /// CurMultiClass - If we are parsing a 'multiclass' definition, this is the 
   /// current value.
   MultiClass *CurMultiClass;
@@ -60,8 +74,10 @@ class TGParser {
   // in the middle of creating in.  For those situations, allow the
   // parser to ignore missing object errors.
   enum IDParseMode {
-    ParseValueMode, // We are parsing a value we expect to look up.
-    ParseNameMode // We are parsing a name of an object that does not yet exist.
+    ParseValueMode,   // We are parsing a value we expect to look up.
+    ParseNameMode,    // We are parsing a name of an object that does not yet
+                      // exist.
+    ParseForeachMode  // We are parsing a foreach init.
   };
 
 public:
@@ -82,6 +98,7 @@ public:
   const std::vector<std::string> &getDependencies() const {
     return Lex.getDependencies();
   }
+
 private:  // Semantic analysis methods.
   bool AddValue(Record *TheRec, SMLoc Loc, const RecordVal &RV);
   bool SetValue(Record *TheRec, SMLoc Loc, Init *ValName, 
@@ -94,6 +111,23 @@ private:  // Semantic analysis methods.
   bool AddSubMultiClass(MultiClass *CurMC,
                         SubMultiClassReference &SubMultiClass);
 
+  // IterRecord: Map an iterator name to a value.
+  struct IterRecord {
+    Init *IterVar;
+    Init *IterValue;
+    IterRecord(Init *Var, Init *Val) : IterVar(Var), IterValue(Val) {}
+  };
+
+  // IterSet: The set of all iterator values at some point in the
+  // iteration space.
+  typedef std::vector<IterRecord> IterSet;
+
+  bool ProcessForeachDefs(Record *CurRec, MultiClass *CurMultiClass,
+                          SMLoc Loc);
+  bool ProcessForeachDefs(Record *CurRec, MultiClass *CurMultiClass,
+                          SMLoc Loc, IterSet &IterVals, ForeachLoop &CurLoop,
+                          LoopVector::iterator NextLoop);
+
 private:  // Parser methods.
   bool ParseObjectList(MultiClass *MC = 0);
   bool ParseObject(MultiClass *MC);
@@ -116,6 +150,7 @@ private:  // Parser methods.
                             SMLoc DefmPrefixLoc);
   bool ParseDefm(MultiClass *CurMultiClass);
   bool ParseDef(MultiClass *CurMultiClass);
+  bool ParseForeach(MultiClass *CurMultiClass);
   bool ParseTopLevelLet(MultiClass *CurMultiClass);
   std::vector<LetRecord> ParseLetList();
 
@@ -125,6 +160,7 @@ private:  // Parser methods.
 
   bool ParseTemplateArgList(Record *CurRec);
   Init *ParseDeclaration(Record *CurRec, bool ParsingTemplateArgs);
+  Init *ParseForeachDeclaration(Init *&ForeachListValue);
 
   SubClassReference ParseSubClassReference(Record *CurRec, bool isDefm);
   SubMultiClassReference ParseSubMultiClassReference(MultiClass *CurMC);
-- 
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