From: Sebastian Redl Date: Mon, 27 Apr 2009 20:27:31 +0000 (+0000) Subject: Improve validation of C++ exception handling: diagnose throwing incomplete types... X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=972041f45bdf8df7ea447221292d7827466ba94b;p=clang Improve validation of C++ exception handling: diagnose throwing incomplete types and jumps into protected try-catch scopes. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70242 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index 0e40e3af44..c6f3b0b50b 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/include/clang/Basic/DiagnosticSemaKinds.td @@ -866,6 +866,10 @@ def note_protected_by_objc_finally : Note< "jump bypasses initialization of @finally block">; def note_protected_by_objc_synchronized : Note< "jump bypasses initialization of @synchronized block">; +def note_protected_by_cxx_try : Note< + "jump bypasses initialization of try block">; +def note_protected_by_cxx_catch : Note< + "jump bypasses initialization of catch block">; def err_func_returning_array_function : Error< "function cannot return array or function type %0">; @@ -1196,6 +1200,11 @@ def err_conditional_ambiguous_ovl : Error< "conditional expression is ambiguous; %0 and %1 can be converted to several " "common types">; +def err_throw_incomplete : Error< + "cannot throw object of incomplete type %0">; +def err_throw_incomplete_ptr : Error< + "cannot throw pointer to object of incomplete type %0">; + def err_invalid_use_of_function_type : Error< "a function type is not allowed here">; def err_invalid_use_of_array_type : Error<"an array type is not allowed here">; diff --git a/lib/Sema/JumpDiagnostics.cpp b/lib/Sema/JumpDiagnostics.cpp index 20473e4306..ae863f2df1 100644 --- a/lib/Sema/JumpDiagnostics.cpp +++ b/lib/Sema/JumpDiagnostics.cpp @@ -15,6 +15,7 @@ #include "Sema.h" #include "clang/AST/Expr.h" #include "clang/AST/StmtObjC.h" +#include "clang/AST/StmtCXX.h" using namespace clang; namespace { @@ -115,7 +116,6 @@ void JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned ParentScope) { // FIXME: diagnose jumps past initialization: required in C++, warning in C. // goto L; int X = 4; L: ; - // FIXME: what about jumps into C++ catch blocks, what are the rules? // If this is a declstmt with a VLA definition, it defines a scope from here // to the end of the containing context. @@ -184,7 +184,27 @@ void JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned ParentScope) { BuildScopeInformation(AS->getSynchBody(), Scopes.size()-1); continue; } - + + // Disallow jumps into any part of a C++ try statement. This is pretty + // much the same as for Obj-C. + if (CXXTryStmt *TS = dyn_cast(SubStmt)) { + Scopes.push_back(GotoScope(ParentScope, diag::note_protected_by_cxx_try, + TS->getSourceRange().getBegin())); + if (Stmt *TryBlock = TS->getTryBlock()) + BuildScopeInformation(TryBlock, Scopes.size()-1); + + // Jump from the catch into the try is not allowed either. + for(unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) { + CXXCatchStmt *CS = TS->getHandler(I); + Scopes.push_back(GotoScope(ParentScope, + diag::note_protected_by_cxx_catch, + CS->getSourceRange().getBegin())); + BuildScopeInformation(CS->getHandlerBlock(), Scopes.size()-1); + } + + continue; + } + // Recursively walk the AST. BuildScopeInformation(SubStmt, ParentScope); } diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h index e30f1287a1..637804ce09 100644 --- a/lib/Sema/Sema.h +++ b/lib/Sema/Sema.h @@ -1494,6 +1494,7 @@ public: //// ActOnCXXThrow - Parse throw expressions. virtual OwningExprResult ActOnCXXThrow(SourceLocation OpLoc, ExprArg expr); + bool CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E); /// ActOnCXXTypeConstructExpr - Parse construction of a specified type. /// Can be interpreted either as function-style casting ("int(x)") diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp index afd67fac55..4c3c85bbf5 100644 --- a/lib/Sema/SemaExprCXX.cpp +++ b/lib/Sema/SemaExprCXX.cpp @@ -88,8 +88,37 @@ Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) { /// ActOnCXXThrow - Parse throw expressions. Action::OwningExprResult Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprArg E) { - return Owned(new (Context) CXXThrowExpr((Expr*)E.release(), Context.VoidTy, - OpLoc)); + Expr *Ex = E.takeAs(); + if (Ex && !Ex->isTypeDependent() && CheckCXXThrowOperand(OpLoc, Ex)) + return ExprError(); + return Owned(new (Context) CXXThrowExpr(Ex, Context.VoidTy, OpLoc)); +} + +/// CheckCXXThrowOperand - Validate the operand of a throw. +bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E) { + // C++ [except.throw]p3: + // [...] adjusting the type from "array of T" or "function returning T" + // to "pointer to T" or "pointer to function returning T", [...] + DefaultFunctionArrayConversion(E); + + // If the type of the exception would be an incomplete type or a pointer + // to an incomplete type other than (cv) void the program is ill-formed. + QualType Ty = E->getType(); + int isPointer = 0; + if (const PointerType* Ptr = Ty->getAsPointerType()) { + Ty = Ptr->getPointeeType(); + isPointer = 1; + } + if (!isPointer || !Ty->isVoidType()) { + if (RequireCompleteType(ThrowLoc, Ty, + isPointer ? diag::err_throw_incomplete_ptr + : diag::err_throw_incomplete, + E->getSourceRange(), SourceRange(), QualType())) + return true; + } + + // FIXME: Construct a temporary here. + return false; } Action::OwningExprResult Sema::ActOnCXXThis(SourceLocation ThisLoc) { diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp index 93e30ec65f..cf240291c7 100644 --- a/lib/Sema/SemaStmt.cpp +++ b/lib/Sema/SemaStmt.cpp @@ -1156,6 +1156,7 @@ Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, // Neither of these are explicitly forbidden, but every compiler detects them // and warns. + CurFunctionNeedsScopeChecking = true; RawHandlers.release(); return Owned(new (Context) CXXTryStmt(TryLoc, static_cast(TryBlock.release()), diff --git a/test/SemaCXX/exceptions.cpp b/test/SemaCXX/exceptions.cpp new file mode 100644 index 0000000000..508f23d148 --- /dev/null +++ b/test/SemaCXX/exceptions.cpp @@ -0,0 +1,67 @@ +// RUN: clang-cc -fsyntax-only -verify %s + +struct A; // expected-note 4 {{forward declaration of 'struct A'}} + +void trys() { + try { + } catch(int i) { // expected-note {{previous definition}} + int j = i; + int i; // expected-error {{redefinition of 'i'}} + } catch(float i) { + } catch(void v) { // expected-error {{cannot catch incomplete type 'void'}} + } catch(A a) { // expected-error {{cannot catch incomplete type 'struct A'}} + } catch(A *a) { // expected-error {{cannot catch pointer to incomplete type 'struct A'}} + } catch(A &a) { // expected-error {{cannot catch reference to incomplete type 'struct A'}} + } catch(...) { + int j = i; // expected-error {{use of undeclared identifier 'i'}} + } + + try { + } catch(...) { // expected-error {{catch-all handler must come last}} + } catch(int) { + } +} + +void throws() { + throw; + throw 0; + throw throw; // expected-error {{cannot throw object of incomplete type 'void'}} + throw (A*)0; // expected-error {{cannot throw pointer to object of incomplete type 'struct A'}} +} + +void jumps() { +l1: + goto l5; + goto l4; // expected-error {{illegal goto into protected scope}} + goto l3; // expected-error {{illegal goto into protected scope}} + goto l2; // expected-error {{illegal goto into protected scope}} + goto l1; + try { // expected-note 4 {{jump bypasses initialization of try block}} + l2: + goto l5; + goto l4; // expected-error {{illegal goto into protected scope}} + goto l3; // expected-error {{illegal goto into protected scope}} + goto l2; + goto l1; + } catch(int) { // expected-note 4 {{jump bypasses initialization of catch block}} + l3: + goto l5; + goto l4; // expected-error {{illegal goto into protected scope}} + goto l3; + goto l2; // expected-error {{illegal goto into protected scope}} + goto l1; + } catch(...) { // expected-note 4 {{jump bypasses initialization of catch block}} + l4: + goto l5; + goto l4; + goto l3; // expected-error {{illegal goto into protected scope}} + goto l2; // expected-error {{illegal goto into protected scope}} + goto l1; + } +l5: + goto l5; + goto l4; // expected-error {{illegal goto into protected scope}} + goto l3; // expected-error {{illegal goto into protected scope}} + goto l2; // expected-error {{illegal goto into protected scope}} + goto l1; +} diff --git a/test/SemaCXX/try-catch.cpp b/test/SemaCXX/try-catch.cpp deleted file mode 100644 index 653deaa5fb..0000000000 --- a/test/SemaCXX/try-catch.cpp +++ /dev/null @@ -1,24 +0,0 @@ -// RUN: clang-cc -fsyntax-only -verify %s - -struct A; // expected-note 3 {{forward declaration of 'struct A'}} - -void f() -{ - try { - } catch(int i) { // expected-note {{previous definition}} - int j = i; - int i; // expected-error {{redefinition of 'i'}} - } catch(float i) { - } catch(void v) { // expected-error {{cannot catch incomplete type 'void'}} - } catch(A a) { // expected-error {{cannot catch incomplete type 'struct A'}} - } catch(A *a) { // expected-error {{cannot catch pointer to incomplete type 'struct A'}} - } catch(A &a) { // expected-error {{cannot catch reference to incomplete type 'struct A'}} - } catch(...) { - int j = i; // expected-error {{use of undeclared identifier 'i'}} - } - - try { - } catch(...) { // expected-error {{catch-all handler must come last}} - } catch(int) { - } -} diff --git a/www/cxx_status.html b/www/cxx_status.html index 4f3e95b7b9..ab8171c4cf 100644 --- a/www/cxx_status.html +++ b/www/cxx_status.html @@ -1638,7 +1638,7 @@ welcome!

15 [except] ✓ ✓ - Illegal gotos are not diagnosed + ✓ @@ -1646,9 +1646,9 @@ welcome!

  15.1 [except.throw] N/A N/A - Does not check for existence of copy constructor and destructor, and some other details - + + Does not check for existence of copy constructor and destructor, and some other details   15.2 [except.ctor] @@ -1662,9 +1662,9 @@ welcome!

  15.3 [except.handle] N/A N/A - Not all constraints are checked, such as existence of return statements in function-try-block handlers of constructors - + + Not all constraints are checked, such as existence of return statements in function-try-block handlers of constructors   15.4 [except.spec] @@ -1710,9 +1710,9 @@ welcome!

  15.6 [except.access] N/A N/A - Redundant - struck from C++0x N/A - + N/A + Redundant - struck from C++0x 16 [cpp]   16.1 [cpp.cond]