Commit af80b8cc authored by Richard Smith's avatar Richard Smith
Browse files

PR44684: Look through parens and similar constructs when determining 

whether a call is to a builtin.

We already had a general mechanism to do this but for some reason
weren't using it. In passing, check for the other unary operators that
can intervene in a reasonably-direct function call (we already handled
'&' but missed '*' and '+').
parent 6f07f304

clang/lib/AST/Expr.cpp

+22 −30
Original line number Diff line number Diff line
@@ -1443,19 +1443,28 @@ void CallExpr::updateDependenciesFromArg(Expr *Arg) { 
Decl *Expr::getReferencedDeclOfCallee() {

  Expr *CEE = IgnoreParenImpCasts();



  while (SubstNonTypeTemplateParmExpr *NTTP

                                = dyn_cast<SubstNonTypeTemplateParmExpr>(CEE)) {

    CEE = NTTP->getReplacement()->IgnoreParenCasts();

  while (SubstNonTypeTemplateParmExpr *NTTP =

             dyn_cast<SubstNonTypeTemplateParmExpr>(CEE)) {

    CEE = NTTP->getReplacement()->IgnoreParenImpCasts();

  }



  // If we're calling a dereference, look at the pointer instead.

  while (true) {

    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(CEE)) {

    if (BO->isPtrMemOp())

      CEE = BO->getRHS()->IgnoreParenCasts();

      if (BO->isPtrMemOp()) {

        CEE = BO->getRHS()->IgnoreParenImpCasts();

        continue;

      }

    } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(CEE)) {

    if (UO->getOpcode() == UO_Deref)

      CEE = UO->getSubExpr()->IgnoreParenCasts();

      if (UO->getOpcode() == UO_Deref || UO->getOpcode() == UO_AddrOf ||

          UO->getOpcode() == UO_Plus) {

        CEE = UO->getSubExpr()->IgnoreParenImpCasts();

        continue;

      }

    }

    break;

  }



  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE))

    return DRE->getDecl();

  if (MemberExpr *ME = dyn_cast<MemberExpr>(CEE))
@@ -1466,28 +1475,11 @@ Decl *Expr::getReferencedDeclOfCallee() { 
  return nullptr;

}



/// getBuiltinCallee - If this is a call to a builtin, return the builtin ID. If

/// not, return 0.

/// If this is a call to a builtin, return the builtin ID. If not, return 0.

unsigned CallExpr::getBuiltinCallee() const {

  // All simple function calls (e.g. func()) are implicitly cast to pointer to

  // function. As a result, we try and obtain the DeclRefExpr from the

  // ImplicitCastExpr.

  const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());

  if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).

    return 0;



  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());

  if (!DRE)

    return 0;



  const FunctionDecl *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl());

  if (!FDecl)

    return 0;



  if (!FDecl->getIdentifier())

    return 0;



  return FDecl->getBuiltinID();

  auto *FDecl =

      dyn_cast_or_null<FunctionDecl>(getCallee()->getReferencedDeclOfCallee());

  return FDecl ? FDecl->getBuiltinID() : 0;

}



bool CallExpr::isUnevaluatedBuiltinCall(const ASTContext &Ctx) const {

clang/lib/AST/ExprConstant.cpp

+1 −1
Original line number Diff line number Diff line
@@ -10660,7 +10660,7 @@ static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info, 














bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,















                                            unsigned BuiltinOp) {













  switch (unsigned BuiltinOp = E->getBuiltinCallee()) {













  switch (BuiltinOp) {















  default:















    return ExprEvaluatorBaseTy::VisitCallExpr(E);















































clang/test/Parser/builtin_classify_type.c



+1
−1






























Original line number
Diff line number
Diff line








@@ -9,7 +9,7 @@ int main() {













  struct foo s;































  static int ary[__builtin_classify_type(a)];













  static int ary2[(__builtin_classify_type)(a)]; // expected-error{{variable length array declaration cannot have 'static' storage duration}}













  static int ary2[(__builtin_classify_type)(a)];















  static int ary3[(*__builtin_classify_type)(a)]; // expected-error{{builtin functions must be directly called}}































  int result;

































clang/test/Sema/constant-builtins.c



+10
−1






























Original line number
Diff line number
Diff line








@@ -25,4 +25,13 @@ short somefunc();





























short t = __builtin_constant_p(5353) ? 42 : somefunc();









































// PR44684













_Static_assert((__builtin_clz)(1u) >= 15, "");













_Static_assert((__builtin_popcount)(1u) == 1, "");













_Static_assert((__builtin_ctz)(2u) == 1, "");













_Static_assert(_Generic(1u,unsigned:__builtin_clz)(1u) >= 15, "");













_Static_assert(_Generic(1u,unsigned:__builtin_popcount)(1u) == 1, "");













_Static_assert(_Generic(1u,unsigned:__builtin_ctz)(2u) == 1, "");



























__SIZE_TYPE__ strlen(const char*);













_Static_assert((__builtin_constant_p(1) ? (***&strlen)("foo") : 0) == 3, "");