Commit fb882976 authored by Nico Weber's avatar Nico Weber
Browse files

[clang] Disallow mixing SEH and Objective-C exceptions 

We already disallow mixing SEH and C++ exceptions, and
mixing SEH and Objective-C exceptions seems to not work (see PR52233).
Emitting an error is friendlier than crashing.

Differential Revision: https://reviews.llvm.org/D112157
parent 503d061d

clang/include/clang/Basic/DiagnosticSemaKinds.td

+2 −1
Original line number Diff line number Diff line
@@ -7516,7 +7516,8 @@ def note_throw_in_function : Note<"function declared non-throwing here">; 
def err_seh_try_outside_functions : Error<

  "cannot use SEH '__try' in blocks, captured regions, or Obj-C method decls">;

def err_mixing_cxx_try_seh_try : Error<

  "cannot use C++ 'try' in the same function as SEH '__try'">;

  "cannot use %select{C++ 'try'|Objective-C '@try'}0 "

  "in the same function as SEH '__try'">;

def err_seh_try_unsupported : Error<

  "SEH '__try' is not supported on this target">;

def note_conflicting_try_here : Note<

clang/include/clang/Sema/ScopeInfo.h

+11 −3
Original line number Diff line number Diff line
@@ -175,8 +175,9 @@ public: 
  /// First 'return' statement in the current function.

  SourceLocation FirstReturnLoc;



  /// First C++ 'try' statement in the current function.

  SourceLocation FirstCXXTryLoc;

  /// First C++ 'try' or ObjC @try statement in the current function.

  SourceLocation FirstCXXOrObjCTryLoc;

  enum { TryLocIsCXX, TryLocIsObjC, Unknown } FirstTryType = Unknown;



  /// First SEH '__try' statement in the current function.

  SourceLocation FirstSEHTryLoc;
@@ -446,7 +447,14 @@ public: 


  void setHasCXXTry(SourceLocation TryLoc) {

    setHasBranchProtectedScope();

    FirstCXXTryLoc = TryLoc;

    FirstCXXOrObjCTryLoc = TryLoc;

    FirstTryType = TryLocIsCXX;

  }



  void setHasObjCTry(SourceLocation TryLoc) {

    setHasBranchProtectedScope();

    FirstCXXOrObjCTryLoc = TryLoc;

    FirstTryType = TryLocIsObjC;

  }



  void setHasSEHTry(SourceLocation TryLoc) {

clang/lib/Sema/ScopeInfo.cpp

+1 −1
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ void FunctionScopeInfo::Clear() { 
  ObjCIsSecondaryInit = false;

  ObjCWarnForNoInitDelegation = false;

  FirstReturnLoc = SourceLocation();

  FirstCXXTryLoc = SourceLocation();

  FirstCXXOrObjCTryLoc = SourceLocation();

  FirstSEHTryLoc = SourceLocation();



  // Coroutine state

clang/lib/Sema/SemaStmt.cpp

+15 −5
Original line number Diff line number Diff line
@@ -4187,7 +4187,14 @@ Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 
  if (!getLangOpts().ObjCExceptions)

    Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";



  setFunctionHasBranchProtectedScope();

  // Objective-C try is incompatible with SEH __try.

  sema::FunctionScopeInfo *FSI = getCurFunction();

  if (FSI->FirstSEHTryLoc.isValid()) {

    Diag(AtLoc, diag::err_mixing_cxx_try_seh_try) << 1;

    Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";

  }



  FSI->setHasObjCTry(AtLoc);

  unsigned NumCatchStmts = CatchStmts.size();

  return ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.data(),

                               NumCatchStmts, Finally);
@@ -4423,7 +4430,7 @@ StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 


  // C++ try is incompatible with SEH __try.

  if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {

    Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);

    Diag(TryLoc, diag::err_mixing_cxx_try_seh_try) << 0;

    Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";

  }
@@ -4507,9 +4514,12 @@ StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc, 
  // SEH __try is incompatible with C++ try. Borland appears to support this,

  // however.

  if (!getLangOpts().Borland) {

    if (FSI->FirstCXXTryLoc.isValid()) {

      Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);

      Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";

    if (FSI->FirstCXXOrObjCTryLoc.isValid()) {

      Diag(TryLoc, diag::err_mixing_cxx_try_seh_try) << FSI->FirstTryType;

      Diag(FSI->FirstCXXOrObjCTryLoc, diag::note_conflicting_try_here)

          << (FSI->FirstTryType == sema::FunctionScopeInfo::TryLocIsCXX

                  ? "'try'"

                  : "'@try'");

    }

  }

clang/test/SemaCXX/exceptions-seh.mm

0 → 100644
+25 −0
Original line number Diff line number Diff line 
// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -fsyntax-only -fexceptions -fobjc-exceptions -verify %s



void might_crash();



void use_seh_after_objc() {

  @try { // expected-note {{conflicting '@try' here}}

    might_crash();

  } @finally {

  }

  __try { // expected-error {{cannot use Objective-C '@try' in the same function as SEH '__try'}}

    might_crash();

  } __except(1) {

  }

}



void use_objc_after_seh() {

  __try { // expected-note {{conflicting '__try' here}}

    might_crash();

  } __except(1) {

  }

  @try { // expected-error {{cannot use Objective-C '@try' in the same function as SEH '__try'}}

    might_crash();

  } @finally {

  }

}