Commit 74ffad29 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r291964: 

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r291964 | rsmith | 2017-01-13 14:16:41 -0800 (Fri, 13 Jan 2017) | 2 lines

PR31631: fix bad CFG (and bogus warnings) when an if-statement has an init-statement and has binary operator as its condition.

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llvm-svn: 291978
parent aa8d52cd

clang/lib/Analysis/CFG.cpp

+36 −41
Original line number Diff line number Diff line
@@ -2175,19 +2175,15 @@ CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 
  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);



  // Create local scope for C++17 if init-stmt if one exists.

  if (Stmt *Init = I->getInit()) {

    LocalScope::const_iterator BeginScopePos = ScopePos;

  if (Stmt *Init = I->getInit())

    addLocalScopeForStmt(Init);

    addAutomaticObjDtors(ScopePos, BeginScopePos, I);

  }



  // Create local scope for possible condition variable.

  // Store scope position. Add implicit destructor.

  if (VarDecl *VD = I->getConditionVariable()) {

    LocalScope::const_iterator BeginScopePos = ScopePos;

  if (VarDecl *VD = I->getConditionVariable())

    addLocalScopeForVarDecl(VD);

    addAutomaticObjDtors(ScopePos, BeginScopePos, I);

  }



  addAutomaticObjDtors(ScopePos, save_scope_pos.get(), I);



  // The block we were processing is now finished.  Make it the successor

  // block.
@@ -2256,12 +2252,14 @@ CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 
  // removes infeasible paths from the control-flow graph by having the

  // control-flow transfer of '&&' or '||' go directly into the then/else

  // blocks directly.

  if (!I->getConditionVariable())

    if (BinaryOperator *Cond =

            dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens()))

      if (Cond->isLogicalOp())

        return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;



  BinaryOperator *Cond =

      I->getConditionVariable()

          ? nullptr

          : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());

  CFGBlock *LastBlock;

  if (Cond && Cond->isLogicalOp())

    LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;

  else {

    // Now create a new block containing the if statement.

    Block = createBlock(false);
@@ -2276,10 +2274,10 @@ CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 
    addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());

    addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());



  // Add the condition as the last statement in the new block.  This may create

  // new blocks as the condition may contain control-flow.  Any newly created

  // blocks will be pointed to be "Block".

  CFGBlock *LastBlock = addStmt(I->getCond());

    // Add the condition as the last statement in the new block.  This may

    // create new blocks as the condition may contain control-flow.  Any newly

    // created blocks will be pointed to be "Block".

    LastBlock = addStmt(I->getCond());



    // If the IfStmt contains a condition variable, add it and its

    // initializer to the CFG.
@@ -2287,6 +2285,7 @@ CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 
      autoCreateBlock();

      LastBlock = addStmt(const_cast<DeclStmt *>(DS));

    }

  }



  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.

  if (Stmt *Init = I->getInit()) {
@@ -3078,19 +3077,15 @@ CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 
  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);



  // Create local scope for C++17 switch init-stmt if one exists.

  if (Stmt *Init = Terminator->getInit()) {

    LocalScope::const_iterator BeginScopePos = ScopePos;

  if (Stmt *Init = Terminator->getInit())

    addLocalScopeForStmt(Init);

    addAutomaticObjDtors(ScopePos, BeginScopePos, Terminator);

  }



  // Create local scope for possible condition variable.

  // Store scope position. Add implicit destructor.

  if (VarDecl *VD = Terminator->getConditionVariable()) {

    LocalScope::const_iterator SwitchBeginScopePos = ScopePos;

  if (VarDecl *VD = Terminator->getConditionVariable())

    addLocalScopeForVarDecl(VD);

    addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator);

  }



  addAutomaticObjDtors(ScopePos, save_scope_pos.get(), Terminator);



  if (Block) {

    if (badCFG)

clang/test/SemaCXX/uninitialized.cpp

+11 −1
Original line number Diff line number Diff line 
// RUN: %clang_cc1 -fsyntax-only -Wall -Wuninitialized -Wno-unused-value -std=c++11 -verify %s

// RUN: %clang_cc1 -fsyntax-only -Wall -Wuninitialized -Wno-unused-value -std=c++1z -verify %s



// definitions for std::move

namespace std {
@@ -1437,3 +1437,13 @@ void array_capture(bool b) { 
    [fname]{};

  }

}



void if_switch_init_stmt(int k) {

  if (int n = 0; (n == k || k > 5)) {}



  if (int n; (n == k || k > 5)) {} // expected-warning {{uninitialized}} expected-note {{initialize}}



  switch (int n = 0; (n == k || k > 5)) {} // expected-warning {{boolean}}



  switch (int n; (n == k || k > 5)) {} // expected-warning {{uninitialized}} expected-note {{initialize}} expected-warning {{boolean}}

}