Parse if statements

llvm-svn: 38844

clang/Parse/ParseExpr.cpp

@@ -0,0 +1,51 @@
+//===--- Expression.cpp - Expression Parsing ------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the Expression parsing implementation.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Parse/Parser.h"
+#include "clang/Basic/Diagnostic.h"
+using namespace llvm;
+using namespace clang;
+
+Parser::ExprTy Parser::ParseExpression() {
+  if (Tok.getKind() == tok::numeric_constant) {
+    ConsumeToken();
+    return 0;
+  }
+  
+  Diag(Tok, diag::err_parse_error);
+  return 0;
+}
+
+///primary-expression:
+///  identifier
+///  constant
+///  string-literal
+///  '(' expression ')'
+
+/// ParseParenExpression - C99 c.5.1p5
+///       primary-expression:
+///         '(' expression ')'
+void Parser::ParseParenExpression() {
+  assert(Tok.getKind() == tok::l_paren && "Not a paren expr!");
+  SourceLocation OpenLoc = Tok.getLocation();
+  ConsumeParen();
+  
+  ParseExpression();
+  
+  if (Tok.getKind() == tok::r_paren) {
+    ConsumeParen();
+  } else {
+    Diag(Tok, diag::err_expected_rparen);
+    Diag(OpenLoc, diag::err_matching);
+  }
+}

clang/Parse/ParseStmt.cpp

@@ -67,19 +67,29 @@ using namespace clang;
 /// [OBC]   '@' 'throw' expression ';'    [TODO]
 /// [OBC]   '@' 'throw' ';'               [TODO]
 /// 
-void Parser::ParseStatementOrDeclaration() {
+void Parser::ParseStatementOrDeclaration(bool OnlyStatement) {
   switch (Tok.getKind()) {
   default:
     Diag(Tok, diag::err_expected_statement_declaration);
     SkipUntil(tok::semi);
     break;
     
-  case tok::semi:  // expression[opt] ';'   -> expression isn't present.
-    ConsumeToken();
-    break;
-  case tok::l_brace:  // compound-statement -> '{}' block
+    // C99 6.8.2: compound-statement -> '{}' block
+  case tok::l_brace:
     ParseCompoundStatement();
     break;
+    // C99 6.8.3: expression[opt] ';'
+  case tok::semi:
+    ConsumeToken();
+    break;
+    
+    // C99 6.8.4.1: if-statement
+  case tok::kw_if:
+    ParseIfStatement();
+    break;
+    
+    
+    // TODO: Handle OnlyStatement..
   }
 }
 
@@ -114,7 +124,7 @@ void Parser::ParseCompoundStatement() {
   ConsumeBrace();  // eat the '{'.
   
   while (Tok.getKind() != tok::r_brace && Tok.getKind() != tok::eof)
-    ParseStatementOrDeclaration();
+    ParseStatementOrDeclaration(false);
   
   // We broke out of the while loop because we found a '}' or EOF.
   if (Tok.getKind() == tok::r_brace)
@@ -122,3 +132,33 @@ void Parser::ParseCompoundStatement() {
   else
     Diag(Tok, diag::err_expected_rbrace);
 }
+
+/// ParseIfStatement
+///       if-statement: [C99 6.8.4.1]
+///         'if' '(' expression ')' statement
+///         'if' '(' expression ')' statement 'else' statement
+void Parser::ParseIfStatement() {
+  assert(Tok.getKind() == tok::kw_if && "Not an if stmt!");
+  ConsumeToken();  // eat the 'if'.
+
+  if (Tok.getKind() != tok::l_paren) {
+    Diag(Tok, diag::err_expected_lparen_after_if, "if");
+    SkipUntil(tok::semi);
+    return;
+  }
+  
+  // Parse the condition.
+  ParseParenExpression();
+  
+  // Read the if condition.
+  ParseStatement();
+  
+  // If it has an else, parse it.
+  if (Tok.getKind() == tok::kw_else) {
+    ConsumeToken();
+    ParseStatement();
+  }
+  
+}
+
+

clang/clang.xcodeproj/project.pbxproj

@@ -12,6 +12,7 @@
 		DE06BECB0A854E4B0050E87E /* Scope.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = DE06BECA0A854E4B0050E87E /* Scope.h */; };
 		DE06BEF40A8558200050E87E /* Decl.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = DE06BEF30A8558200050E87E /* Decl.h */; };
 		DE06CC180A899E110050E87E /* Statement.cpp in Sources */ = {isa = PBXBuildFile; fileRef = DE06CC170A899E110050E87E /* Statement.cpp */; };
+		DE06CEC00A8AE7800050E87E /* Expression.cpp in Sources */ = {isa = PBXBuildFile; fileRef = DE06CEBF0A8AE7800050E87E /* Expression.cpp */; };
 		DE1F22030A7D852A00FBF588 /* Parser.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = DE1F22020A7D852A00FBF588 /* Parser.h */; };
 		DE1F22200A7D879000FBF588 /* ParserActions.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = DE1F221F0A7D879000FBF588 /* ParserActions.h */; };
 		DE1F24700A7DC99000FBF588 /* Actions.cpp in Sources */ = {isa = PBXBuildFile; fileRef = DE1F246D0A7DC99000FBF588 /* Actions.cpp */; };
@@ -116,6 +117,7 @@
 		DE06BECA0A854E4B0050E87E /* Scope.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; name = Scope.h; path = clang/Parse/Scope.h; sourceTree = "<group>"; };
 		DE06BEF30A8558200050E87E /* Decl.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; name = Decl.h; path = clang/Parse/Decl.h; sourceTree = "<group>"; };
 		DE06CC170A899E110050E87E /* Statement.cpp */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.cpp.cpp; name = Statement.cpp; path = Parse/Statement.cpp; sourceTree = "<group>"; };
+		DE06CEBF0A8AE7800050E87E /* Expression.cpp */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.cpp.cpp; name = Expression.cpp; path = Parse/Expression.cpp; sourceTree = "<group>"; };
 		DE1F22020A7D852A00FBF588 /* Parser.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; name = Parser.h; path = clang/Parse/Parser.h; sourceTree = "<group>"; };
 		DE1F221F0A7D879000FBF588 /* ParserActions.h */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.c.h; name = ParserActions.h; path = clang/Parse/ParserActions.h; sourceTree = "<group>"; };
 		DE1F246D0A7DC99000FBF588 /* Actions.cpp */ = {isa = PBXFileReference; fileEncoding = 30; lastKnownFileType = sourcecode.cpp.cpp; name = Actions.cpp; path = Parse/Actions.cpp; sourceTree = "<group>"; };
@@ -227,6 +229,7 @@
 			children = (
 				DE1F246D0A7DC99000FBF588 /* Actions.cpp */,
 				DE1F257A0A7DD86800FBF588 /* Declarations.cpp */,
+				DE06CEBF0A8AE7800050E87E /* Expression.cpp */,
 				DE1F246E0A7DC99000FBF588 /* Parse.cpp */,
 				DE1F246F0A7DC99000FBF588 /* ParseDeclarations.cpp */,
 				DE06BEC80A854E390050E87E /* Scope.cpp */,
@@ -386,6 +389,7 @@
 				DE1F257B0A7DD86800FBF588 /* Declarations.cpp in Sources */,
 				DE06BEC90A854E390050E87E /* Scope.cpp in Sources */,
 				DE06CC180A899E110050E87E /* Statement.cpp in Sources */,
+				DE06CEC00A8AE7800050E87E /* Expression.cpp in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

clang/include/clang/Basic/DiagnosticKinds.def

@@ -274,6 +274,8 @@ DIAG(err_expected_after_declarator, ERROR,
      "expected '=', ',', ';', 'asm', or '__attribute__' after declarator")
 DIAG(err_expected_statement_declaration, ERROR,
      "expected statement or declaration")
+DIAG(err_expected_lparen_after_if, ERROR,
+     "expected '(' after '%s'")
 
 /// err_matching - this is used as a continuation of a previous error, e.g. to 
 /// specify the '(' when we expected a ')'.  This should probably be some

clang/include/clang/Parse/Parser.h

@@ -158,14 +158,21 @@ private:
 
   //===--------------------------------------------------------------------===//
   // C99 6.8: Statements and Blocks.
-  void ParseStatementOrDeclaration();
+  void ParseStatement() { ParseStatementOrDeclaration(true); }
+  void ParseStatementOrDeclaration(bool OnlyStatement = false);
   void ParseCompoundStatement();
+  void ParseIfStatement();
 
   //===--------------------------------------------------------------------===//
   // C99 6.7: Declarations.
   void ParseDeclarationSpecifiers(DeclSpec &DS);
   bool isDeclarationSpecifier() const;
   
+  //===--------------------------------------------------------------------===//
+  // C99 6.5: Expressions.
+  //ExprTy ParseExpression();  // Above.
+  void ParseParenExpression();
+  
   /// ParseDeclarator - Parse and verify a newly-initialized declarator.
   void ParseDeclarator(Declarator &D);
   void ParseDeclaratorInternal(Declarator &D);