From fae8b1de47c004fefaa6c2683ae193d465b9d93f Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Thu, 24 May 2012 22:17:39 +0000
Subject: [PATCH] Add support for range expressions in TableGen foreach loops.

Like this:

  foreach i = 0-127 in ...

Use braces for composite ranges:

  foreach i = {0-3,9-7} in ...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157432 91177308-0d34-0410-b5e6-96231b3b80d8
---
 docs/TableGenFundamentals.html |  8 +++--
 lib/TableGen/TGParser.cpp      | 65 ++++++++++++++++++++++++++--------
 test/TableGen/ForeachLoop.td   | 23 ++++++++++--
 3 files changed, 77 insertions(+), 19 deletions(-)

diff --git a/docs/TableGenFundamentals.html b/docs/TableGenFundamentals.html
index 58f9876d721..5490eebb4fe 100644
--- a/docs/TableGenFundamentals.html
+++ b/docs/TableGenFundamentals.html
@@ -402,14 +402,18 @@ which case the user must specify it explicitly.</dd>
 <dt><tt>list[4-7,17,2-3]</tt></dt>
   <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
   it.  Elements may be included multiple times.</dd>
-<dt><tt>foreach &lt;var&gt; = &lt;list&gt; in { &lt;body&gt; }</tt></dt>
-<dt><tt>foreach &lt;var&gt; = &lt;list&gt; in &lt;def&gt;</tt></dt>
+<dt><tt>foreach &lt;var&gt; = [ &lt;list&gt; ] in { &lt;body&gt; }</tt></dt>
+<dt><tt>foreach &lt;var&gt; = [ &lt;list&gt; ] in &lt;def&gt;</tt></dt>
   <dd> Replicate &lt;body&gt; or &lt;def&gt;, replacing instances of
   &lt;var&gt; with each value in &lt;list&gt;.  &lt;var&gt; is scoped at the
   level of the <tt>foreach</tt> loop and must not conflict with any other object
   introduced in &lt;body&gt; or &lt;def&gt;.  Currently only <tt>def</tt>s are
   expanded within &lt;body&gt;.
   </dd>
+<dt><tt>foreach &lt;var&gt; = 0-15 in ...</tt></dt>
+<dt><tt>foreach &lt;var&gt; = {0-15,32-47} in ...</tt></dt>
+  <dd>Loop over ranges of integers. The braces are required for multiple
+  ranges.</dd>
 <dt><tt>(DEF a, b)</tt></dt>
   <dd>a dag value.  The first element is required to be a record definition, the
   remaining elements in the list may be arbitrary other values, including nested
diff --git a/lib/TableGen/TGParser.cpp b/lib/TableGen/TGParser.cpp
index b23f4100136..94246778007 100644
--- a/lib/TableGen/TGParser.cpp
+++ b/lib/TableGen/TGParser.cpp
@@ -1697,7 +1697,9 @@ Init *TGParser::ParseDeclaration(Record *CurRec,
 /// 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
+///  ForeachDeclaration ::= ID '=' '[' ValueList ']'
+///  ForeachDeclaration ::= ID '=' '{' RangeList '}'
+///  ForeachDeclaration ::= ID '=' RangePiece
 ///
 VarInit *TGParser::ParseForeachDeclaration(ListInit *&ForeachListValue) {
   if (Lex.getCode() != tgtok::Id) {
@@ -1715,26 +1717,59 @@ VarInit *TGParser::ParseForeachDeclaration(ListInit *&ForeachListValue) {
   }
   Lex.Lex();  // Eat the '='
 
-  // Expect a list initializer.
-  Init *List = ParseSimpleValue(0, 0, ParseForeachMode);
+  RecTy *IterType = 0;
+  std::vector<unsigned> Ranges;
 
-  ForeachListValue = dynamic_cast<ListInit*>(List);
-  if (ForeachListValue == 0) {
-    TokError("Expected a Value list");
-    return 0;
+  switch (Lex.getCode()) {
+  default: TokError("Unknown token when expecting a range list"); return 0;
+  case tgtok::l_square: { // '[' ValueList ']'
+    Init *List = ParseSimpleValue(0, 0, ParseForeachMode);
+    ForeachListValue = dynamic_cast<ListInit*>(List);
+    if (ForeachListValue == 0) {
+      TokError("Expected a Value list");
+      return 0;
+    }
+    RecTy *ValueType = ForeachListValue->getType();
+    ListRecTy *ListType = dynamic_cast<ListRecTy *>(ValueType);
+    if (ListType == 0) {
+      TokError("Value list is not of list type");
+      return 0;
+    }
+    IterType = ListType->getElementType();
+    break;
   }
 
-  RecTy *ValueType = ForeachListValue->getType();
-  ListRecTy *ListType = dynamic_cast<ListRecTy *>(ValueType);
-  if (ListType == 0) {
-    TokError("Value list is not of list type");
-    return 0;
+  case tgtok::IntVal: { // RangePiece.
+    if (ParseRangePiece(Ranges))
+      return 0;
+    break;
   }
 
-  RecTy *IterType = ListType->getElementType();
-  VarInit *IterVar = VarInit::get(DeclName, IterType);
+  case tgtok::l_brace: { // '{' RangeList '}'
+    Lex.Lex(); // eat the '{'
+    Ranges = ParseRangeList();
+    if (Lex.getCode() != tgtok::r_brace) {
+      TokError("expected '}' at end of bit range list");
+      return 0;
+    }
+    Lex.Lex();
+    break;
+  }
+  }
 
-  return IterVar;
+  if (!Ranges.empty()) {
+    assert(!IterType && "Type already initialized?");
+    IterType = IntRecTy::get();
+    std::vector<Init*> Values;
+    for (unsigned i = 0, e = Ranges.size(); i != e; ++i)
+      Values.push_back(IntInit::get(Ranges[i]));
+    ForeachListValue = ListInit::get(Values, IterType);
+  }
+
+  if (!IterType)
+    return 0;
+
+  return VarInit::get(DeclName, IterType);
 }
 
 /// ParseTemplateArgList - Read a template argument list, which is a non-empty
diff --git a/test/TableGen/ForeachLoop.td b/test/TableGen/ForeachLoop.td
index 342609643cc..4aacc74d8aa 100644
--- a/test/TableGen/ForeachLoop.td
+++ b/test/TableGen/ForeachLoop.td
@@ -6,11 +6,19 @@ class Register<string name, int idx> {
   int Index = idx;
 }
 
+// CHECK-NOT: !strconcat
+
+foreach i = 0-3 in
+  def Q#i : Register<"Q"#i, i>;
+
+// CHECK: def Q0
+// CHECK: def Q1
+// CHECK: def Q2
+// CHECK: def Q3
+
 foreach i = [0, 1, 2, 3, 4, 5, 6, 7] in
   def R#i : Register<"R"#i, i>;
 
-// CHECK-NOT: !strconcat
-
 // CHECK: def R0
 // CHECK: string Name = "R0";
 // CHECK: int Index = 0;
@@ -42,3 +50,14 @@ foreach i = [0, 1, 2, 3, 4, 5, 6, 7] in
 // CHECK: def R7
 // CHECK: string Name = "R7";
 // CHECK: int Index = 7;
+
+foreach i = {0-3,9-7} in
+  def S#i : Register<"Q"#i, i>;
+
+// CHECK: def S0
+// CHECK: def S1
+// CHECK: def S2
+// CHECK: def S3
+// CHECK: def S7
+// CHECK: def S8
+// CHECK: def S9