[Kaleidoscope] Clang-format the Kaleidoscope tutorials.

Also reduces changes between tutorial chapters.

llvm-svn: 245472
diff --git a/llvm/docs/tutorial/LangImpl5.rst b/llvm/docs/tutorial/LangImpl5.rst
index add0e18..c0420fa 100644
--- a/llvm/docs/tutorial/LangImpl5.rst
+++ b/llvm/docs/tutorial/LangImpl5.rst
@@ -66,7 +66,9 @@
 .. code-block:: c++
 
       // control
-      tok_if = -6, tok_then = -7, tok_else = -8,
+      tok_if = -6,
+      tok_then = -7,
+      tok_else = -8,
 
 Once we have that, we recognize the new keywords in the lexer. This is
 pretty simple stuff:
@@ -74,11 +76,16 @@
 .. code-block:: c++
 
         ...
-        if (IdentifierStr == "def") return tok_def;
-        if (IdentifierStr == "extern") return tok_extern;
-        if (IdentifierStr == "if") return tok_if;
-        if (IdentifierStr == "then") return tok_then;
-        if (IdentifierStr == "else") return tok_else;
+        if (IdentifierStr == "def")
+          return tok_def;
+        if (IdentifierStr == "extern")
+          return tok_extern;
+        if (IdentifierStr == "if")
+          return tok_if;
+        if (IdentifierStr == "then")
+          return tok_then;
+        if (IdentifierStr == "else")
+          return tok_else;
         return tok_identifier;
 
 AST Extensions for If/Then/Else
@@ -91,6 +98,7 @@
     /// IfExprAST - Expression class for if/then/else.
     class IfExprAST : public ExprAST {
       std::unique<ExprAST> Cond, Then, Else;
+
     public:
       IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
                 std::unique_ptr<ExprAST> Else)
@@ -115,14 +123,16 @@
 
       // condition.
       auto Cond = ParseExpression();
-      if (!Cond) return nullptr;
+      if (!Cond)
+        return nullptr;
 
       if (CurTok != tok_then)
         return Error("expected then");
       getNextToken();  // eat the then
 
       auto Then = ParseExpression();
-      if (Then) return nullptr;
+      if (!Then)
+        return nullptr;
 
       if (CurTok != tok_else)
         return Error("expected else");
@@ -130,7 +140,8 @@
       getNextToken();
 
       auto Else = ParseExpression();
-      if (!Else) return nullptr;
+      if (!Else)
+        return nullptr;
 
       return llvm::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
                                           std::move(Else));
@@ -142,11 +153,16 @@
 
     static std::unique_ptr<ExprAST> ParsePrimary() {
       switch (CurTok) {
-      default: return Error("unknown token when expecting an expression");
-      case tok_identifier: return ParseIdentifierExpr();
-      case tok_number:     return ParseNumberExpr();
-      case '(':            return ParseParenExpr();
-      case tok_if:         return ParseIfExpr();
+      default:
+        return Error("unknown token when expecting an expression");
+      case tok_identifier:
+        return ParseIdentifierExpr();
+      case tok_number:
+        return ParseNumberExpr();
+      case '(':
+        return ParseParenExpr();
+      case tok_if:
+        return ParseIfExpr();
       }
     }
 
@@ -271,12 +287,12 @@
 
     Value *IfExprAST::Codegen() {
       Value *CondV = Cond->Codegen();
-      if (!CondV) return nullptr;
+      if (!CondV)
+        return nullptr;
 
       // Convert condition to a bool by comparing equal to 0.0.
-      CondV = Builder.CreateFCmpONE(CondV,
-                                  ConstantFP::get(getGlobalContext(), APFloat(0.0)),
-                                    "ifcond");
+      CondV = Builder.CreateFCmpONE(
+          CondV, ConstantFP::get(getGlobalContext(), APFloat(0.0)), "ifcond");
 
 This code is straightforward and similar to what we saw before. We emit
 the expression for the condition, then compare that value to zero to get
@@ -288,7 +304,8 @@
 
       // Create blocks for the then and else cases.  Insert the 'then' block at the
       // end of the function.
-      BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
+      BasicBlock *ThenBB =
+          BasicBlock::Create(getGlobalContext(), "then", TheFunction);
       BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
       BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
 
@@ -321,7 +338,8 @@
       Builder.SetInsertPoint(ThenBB);
 
       Value *ThenV = Then->Codegen();
-      if (ThenV == 0) return 0;
+      if (!ThenV)
+        return nullptr;
 
       Builder.CreateBr(MergeBB);
       // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
@@ -362,7 +380,8 @@
       Builder.SetInsertPoint(ElseBB);
 
       Value *ElseV = Else->Codegen();
-      if (ElseV == 0) return 0;
+      if (!ElseV)
+        return nullptr;
 
       Builder.CreateBr(MergeBB);
       // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
@@ -380,8 +399,8 @@
       // Emit merge block.
       TheFunction->getBasicBlockList().push_back(MergeBB);
       Builder.SetInsertPoint(MergeBB);
-      PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
-                                      "iftmp");
+      PHINode *PN =
+        Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2, "iftmp");
 
       PN->addIncoming(ThenV, ThenBB);
       PN->addIncoming(ElseV, ElseBB);
@@ -446,13 +465,20 @@
       tok_for = -9, tok_in = -10
 
       ... in gettok ...
-      if (IdentifierStr == "def") return tok_def;
-      if (IdentifierStr == "extern") return tok_extern;
-      if (IdentifierStr == "if") return tok_if;
-      if (IdentifierStr == "then") return tok_then;
-      if (IdentifierStr == "else") return tok_else;
-      if (IdentifierStr == "for") return tok_for;
-      if (IdentifierStr == "in") return tok_in;
+      if (IdentifierStr == "def")
+        return tok_def;
+      if (IdentifierStr == "extern")
+        return tok_extern;
+      if (IdentifierStr == "if")
+        return tok_if;
+      if (IdentifierStr == "then")
+        return tok_then;
+      if (IdentifierStr == "else")
+        return tok_else;
+      if (IdentifierStr == "for")
+        return tok_for;
+      if (IdentifierStr == "in")
+        return tok_in;
       return tok_identifier;
 
 AST Extensions for the 'for' Loop
@@ -467,6 +493,7 @@
     class ForExprAST : public ExprAST {
       std::string VarName;
       std::unique_ptr<ExprAST> Start, End, Step, Body;
+
     public:
       ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
                  std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
@@ -502,20 +529,23 @@
 
 
       auto Start = ParseExpression();
-      if (!Start) return nullptr;
+      if (!Start)
+        return nullptr;
       if (CurTok != ',')
         return Error("expected ',' after for start value");
       getNextToken();
 
       auto End = ParseExpression();
-      if (!End) return nullptr;
+      if (!End)
+        return nullptr;
 
       // The step value is optional.
       std::unique_ptr<ExprAST> Step;
       if (CurTok == ',') {
         getNextToken();
         Step = ParseExpression();
-        if (!Step) return nullptr;
+        if (!Step)
+          return nullptr;
       }
 
       if (CurTok != tok_in)
@@ -523,7 +553,8 @@
       getNextToken();  // eat 'in'.
 
       auto Body = ParseExpression();
-      if (!Body) return nullptr;
+      if (!Body)
+        return nullptr;
 
       return llvm::make_unique<ForExprAST>(IdName, std::move(Start),
                                            std::move(End), std::move(Step),
@@ -593,7 +624,8 @@
       // block.
       Function *TheFunction = Builder.GetInsertBlock()->getParent();
       BasicBlock *PreheaderBB = Builder.GetInsertBlock();
-      BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
+      BasicBlock *LoopBB =
+          BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
 
       // Insert an explicit fall through from the current block to the LoopBB.
       Builder.CreateBr(LoopBB);
@@ -610,7 +642,8 @@
       Builder.SetInsertPoint(LoopBB);
 
       // Start the PHI node with an entry for Start.
-      PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2, VarName.c_str());
+      PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()),
+                                            2, VarName.c_str());
       Variable->addIncoming(StartVal, PreheaderBB);
 
 Now that the "preheader" for the loop is set up, we switch to emitting
@@ -630,8 +663,8 @@
       // Emit the body of the loop.  This, like any other expr, can change the
       // current BB.  Note that we ignore the value computed by the body, but don't
       // allow an error.
-      if (Body->Codegen() == 0)
-        return 0;
+      if (!Body->Codegen())
+        return nullptr;
 
 Now the code starts to get more interesting. Our 'for' loop introduces a
 new variable to the symbol table. This means that our symbol table can
@@ -653,10 +686,11 @@
 .. code-block:: c++
 
       // Emit the step value.
-      Value *StepVal;
+      Value *StepVal = nullptr;
       if (Step) {
         StepVal = Step->Codegen();
-        if (StepVal == 0) return 0;
+        if (!StepVal)
+          return nullptr;
       } else {
         // If not specified, use 1.0.
         StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
@@ -673,12 +707,12 @@
 
       // Compute the end condition.
       Value *EndCond = End->Codegen();
-      if (EndCond == 0) return EndCond;
+      if (!EndCond)
+        return nullptr;
 
       // Convert condition to a bool by comparing equal to 0.0.
-      EndCond = Builder.CreateFCmpONE(EndCond,
-                                  ConstantFP::get(getGlobalContext(), APFloat(0.0)),
-                                      "loopcond");
+      EndCond = Builder.CreateFCmpONE(
+          EndCond, ConstantFP::get(getGlobalContext(), APFloat(0.0)), "loopcond");
 
 Finally, we evaluate the exit value of the loop, to determine whether
 the loop should exit. This mirrors the condition evaluation for the
@@ -688,7 +722,8 @@
 
       // Create the "after loop" block and insert it.
       BasicBlock *LoopEndBB = Builder.GetInsertBlock();
-      BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
+      BasicBlock *AfterBB =
+          BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
 
       // Insert the conditional branch into the end of LoopEndBB.
       Builder.CreateCondBr(EndCond, LoopBB, AfterBB);