Author: Corentin Jabot Date: 2023-07-11T21:41:14+02:00 New Revision: b0cc947b5d0a74f4ffe63c53b32978b21498e72e
URL: https://github.com/llvm/llvm-project/commit/b0cc947b5d0a74f4ffe63c53b32978b21498e72e DIFF: https://github.com/llvm/llvm-project/commit/b0cc947b5d0a74f4ffe63c53b32978b21498e72e.diff LOG: [Clang] Diagnose jumps into statement expressions Such jumps are not allowed by GCC and allowing them can lead to situations where we jumps into unevaluated statements. Fixes #63682 Reviewed By: aaron.ballman, #clang-language-wg Differential Revision: https://reviews.llvm.org/D154696 Added: Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/JumpDiagnostics.cpp clang/lib/Sema/SemaExpr.cpp clang/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp clang/test/Sema/asm-goto.cpp clang/test/Sema/scope-check.c clang/test/SemaCXX/constant-expression-cxx14.cpp clang/test/SemaObjC/scope-check.m Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 6a1e2fc3ea0e64..1f025097babc95 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -582,6 +582,9 @@ Bug Fixes in This Version (`#50243 <https://github.com/llvm/llvm-project/issues/50243>`_), (`#48636 <https://github.com/llvm/llvm-project/issues/48636>`_), (`#50320 <https://github.com/llvm/llvm-project/issues/50320>`_). +- Correcly diagnose jumps into statement expressions. + This ensures the behavior of Clang is consistent with GCC. + (`#63682 <https://github.com/llvm/llvm-project/issues/63682>`_) Bug Fixes to Compiler Builtins ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index eea4d4961c077a..695cf9bce93e87 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -6196,6 +6196,8 @@ def note_enters_block_captures_non_trivial_c_struct : Note< "to destroy">; def note_enters_compound_literal_scope : Note< "jump enters lifetime of a compound literal that is non-trivial to destruct">; +def note_enters_statement_expression : Note< + "jump enters a statement expression">; def note_exits_cleanup : Note< "jump exits scope of variable with __attribute__((cleanup))">; diff --git a/clang/lib/Sema/JumpDiagnostics.cpp b/clang/lib/Sema/JumpDiagnostics.cpp index bd2ce9a93e7e03..45e3cc2b00f0e8 100644 --- a/clang/lib/Sema/JumpDiagnostics.cpp +++ b/clang/lib/Sema/JumpDiagnostics.cpp @@ -477,6 +477,21 @@ void JumpScopeChecker::BuildScopeInformation(Stmt *S, return; } + case Stmt::StmtExprClass: { + // [GNU] + // Jumping into a statement expression with goto or using + // a switch statement outside the statement expression with + // a case or default label inside the statement expression is not permitted. + // Jumping out of a statement expression is permitted. + StmtExpr *SE = cast<StmtExpr>(S); + unsigned NewParentScope = Scopes.size(); + Scopes.push_back(GotoScope(ParentScope, + diag::note_enters_statement_expression, + /*OutDiag=*/0, SE->getBeginLoc())); + BuildScopeInformation(SE->getSubStmt(), NewParentScope); + return; + } + case Stmt::ObjCAtTryStmtClass: { // Disallow jumps into any part of an @try statement by pushing a scope and // walking all sub-stmts in that scope. diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index 56e9c4ca133278..6cebb7e2dd540d 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -16490,6 +16490,8 @@ ExprResult Sema::ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc, void Sema::ActOnStartStmtExpr() { PushExpressionEvaluationContext(ExprEvalContexts.back().Context); + // Make sure we diagnose jumping into a statement expression. + setFunctionHasBranchProtectedScope(); } void Sema::ActOnStmtExprError() { diff --git a/clang/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp b/clang/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp index 0c357db764a92a..55af13bfc0ef3a 100644 --- a/clang/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp +++ b/clang/test/CXX/stmt.stmt/stmt.select/stmt.if/p2.cpp @@ -153,7 +153,8 @@ a: if constexpr(sizeof(n) == 4) // expected-error {{redefinition}} expected-not void evil_things() { goto evil_label; // expected-error {{cannot jump}} - if constexpr (true || ({evil_label: false;})) {} // expected-note {{constexpr if}} + if constexpr (true || ({evil_label: false;})) {} // expected-note {{constexpr if}} \ + // expected-note {{jump enters a statement expression}} if constexpr (true) // expected-note {{constexpr if}} goto surprise; // expected-error {{cannot jump}} diff --git a/clang/test/Sema/asm-goto.cpp b/clang/test/Sema/asm-goto.cpp index 64addd9d75b6ef..8e9aaa4382a651 100644 --- a/clang/test/Sema/asm-goto.cpp +++ b/clang/test/Sema/asm-goto.cpp @@ -50,8 +50,9 @@ int test3(int n) // expected-error@+2 {{cannot jump from this asm goto statement to one of its possible targets}} // expected-error@+1 {{cannot jump from this asm goto statement to one of its possible targets}} asm volatile goto("testl %0, %0; jne %l1;" :: "r"(n)::label_true, loop); - // expected-note@+2 {{jump bypasses initialization of variable length array}} - // expected-note@+1 {{possible target of asm goto statement}} + // expected-note@+3 {{jump bypasses initialization of variable length array}} + // expected-note@+2 {{possible target of asm goto statement}} + // expected-note@+1 {{jump enters a statement expression}} return ({int a[n];label_true: 2;}); // expected-note@+1 {{jump bypasses initialization of variable length array}} int b[n]; diff --git a/clang/test/Sema/scope-check.c b/clang/test/Sema/scope-check.c index d8201780635365..c6aa421b3ebdef 100644 --- a/clang/test/Sema/scope-check.c +++ b/clang/test/Sema/scope-check.c @@ -65,7 +65,8 @@ int test8(int x) { // Statement expressions. goto L3; // expected-error {{cannot jump from this goto statement to its label}} - int Y = ({ int a[x]; // expected-note {{jump bypasses initialization of variable length array}} + int Y = ({ int a[x]; // expected-note {{jump bypasses initialization of variable length array}} \ + // expected-note {{jump enters a statement expression}} L3: 4; }); goto L4; // expected-error {{cannot jump from this goto statement to its label}} @@ -107,25 +108,25 @@ int test8(int x) { 4; })]; L10:; // bad } - + { // FIXME: Crashes goto checker. //goto L11;// ok //int A[({ L11: 4; })]; } - + { goto L12; - + int y = 4; // fixme-warn: skips initializer. L12: ; } - + // Statement expressions 2. goto L1; // expected-error {{cannot jump from this goto statement to its label}} - return x == ({ - int a[x]; // expected-note {{jump bypasses initialization of variable length array}} + return x == ({ // expected-note {{jump enters a statement expression}} + int a[x]; // expected-note {{jump bypasses initialization of variable length array}} L1: 42; }); } @@ -231,3 +232,27 @@ void test15(int n, void *pc) { } int test16(int [sizeof &&z]); // expected-error {{use of address-of-label extension outside of a function body}} + +void GH63682() { + { + goto L; // expected-error {{cannot jump from this goto statement to its label}} + (void)sizeof (int){({ L:; 1; })}; // expected-note {{jump enters a statement expression}} + } + { + goto M; // expected-error {{cannot jump from this goto statement to its label}} + (void)({ M:; 1; }); // expected-note {{jump enters a statement expression}} + } + { + (void)({ goto N; 1; }); // ok + N: ; + } + { + (void)sizeof (int){({ goto O; 1; })}; // ok (not evaluated) + O: ; + } + { + (void)sizeof(({goto P;}), 0); // expected-error {{cannot jump from this goto statement to its label}} + return; + (void)({P:1;}); // expected-note {{jump enters a statement expression}} + } +} diff --git a/clang/test/SemaCXX/constant-expression-cxx14.cpp b/clang/test/SemaCXX/constant-expression-cxx14.cpp index 52a7cceea2a3fd..cf242aaf90aa63 100644 --- a/clang/test/SemaCXX/constant-expression-cxx14.cpp +++ b/clang/test/SemaCXX/constant-expression-cxx14.cpp @@ -831,8 +831,9 @@ namespace StmtExpr { case 0: return 0; - ({ - case 1: // expected-note {{not supported}} + ({ // expected-note {{jump enters a statement expression}} + case 1:// expected-error {{cannot jump from switch statement to this case label}} \ + // expected-note {{not supported}} return 1; }); } diff --git a/clang/test/SemaObjC/scope-check.m b/clang/test/SemaObjC/scope-check.m index c6f88f26164ab6..9cd9356c1d1d10 100644 --- a/clang/test/SemaObjC/scope-check.m +++ b/clang/test/SemaObjC/scope-check.m @@ -15,7 +15,7 @@ void test1(void) { } @finally {// expected-note {{jump bypasses initialization of @finally block}} L3: ; } - + @try { goto L4; // expected-error{{cannot jump}} goto L5; // expected-error{{cannot jump}} @@ -27,8 +27,8 @@ void test1(void) { } @finally { // expected-note {{jump bypasses initialization of @finally block}} L4: ; } - - + + @try { // expected-note 2 {{jump bypasses initialization of @try block}} L7: ; } @catch (C *c) { @@ -36,20 +36,19 @@ void test1(void) { } @finally { goto L7; // expected-error{{cannot jump}} } - + goto L8; // expected-error{{cannot jump}} - @try { + @try { } @catch (A *c) { } @catch (B *c) { } @catch (C *c) { // expected-note {{jump bypasses initialization of @catch block}} L8: ; } - + id X; goto L9; // expected-error{{cannot jump}} - goto L10; // ok - @synchronized // expected-note {{jump bypasses initialization of @synchronized block}} - ( ({ L10: ; X; })) { + @synchronized (X) // expected-note {{jump bypasses initialization of @synchronized block}} + { L9: ; } @@ -88,7 +87,7 @@ + (void)meth2 { goto L0; // expected-error {{cannot jump}} typedef int A[n]; // expected-note {{jump bypasses initialization of VLA typedef}} L0: - + goto L1; // expected-error {{cannot jump}} A b, c[10]; // expected-note 2 {{jump bypasses initialization of variable length array}} L1: _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
