Author: Bill Wendling Date: 2022-05-03T11:23:12-07:00 New Revision: f2639cf3fe46c30ad450cc2533c81eacd4788c33
URL: https://github.com/llvm/llvm-project/commit/f2639cf3fe46c30ad450cc2533c81eacd4788c33 DIFF: https://github.com/llvm/llvm-project/commit/f2639cf3fe46c30ad450cc2533c81eacd4788c33.diff LOG: [randstruct] Move initializer check to be more effective If a randomized structure has an initializer with a dedicated initializer in it, the field initialzed by that dedicated initializer may end up at the end of the RecordDecl. This however may skip the random layout initization check. struct t { int a, b, c, d, e; } x = { .a = 2, 4, 5, 6 }; Let's say that "a" is lands as the last field after randomization. The call to CheckDesignatedInitializer sets the iterator to the end of the initializer list. During the next iteration of the initializer list check, it detects that and fails to issue the error about initializing a randomized struct with non-designated initializer. Instead, it issues an error about "excess elements in struct initializer", which is confusing under these circumstances. Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D124694 Added: Modified: clang/lib/Sema/SemaInit.cpp clang/test/Sema/init-randomized-struct.c Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp index 79c92bde3b770..016ff5ded25fb 100644 --- a/clang/lib/Sema/SemaInit.cpp +++ b/clang/lib/Sema/SemaInit.cpp @@ -2170,11 +2170,6 @@ void InitListChecker::CheckStructUnionTypes( continue; } - if (Field == FieldEnd) { - // We've run out of fields. We're done. - break; - } - // Check if this is an initializer of forms: // // struct foo f = {}; @@ -2204,6 +2199,11 @@ void InitListChecker::CheckStructUnionTypes( break; } + if (Field == FieldEnd) { + // We've run out of fields. We're done. + break; + } + // We've already initialized a member of a union. We're done. if (InitializedSomething && DeclType->isUnionType()) break; diff --git a/clang/test/Sema/init-randomized-struct.c b/clang/test/Sema/init-randomized-struct.c index a708d6a0cfd05..d421597fa522f 100644 --- a/clang/test/Sema/init-randomized-struct.c +++ b/clang/test/Sema/init-randomized-struct.c @@ -1,6 +1,13 @@ -// RUN: %clang_cc1 -triple=x86_64-unknown-linux -frandomize-layout-seed=1234567890abcdef \ +// RUN: %clang_cc1 -triple=x86_64-unknown-linux -frandomize-layout-seed=1234567890abcded \ // RUN: -verify -fsyntax-only -Werror %s +// NOTE: The current seed (1234567890abcded) is specifically chosen because it +// uncovered a bug in diagnostics. With it the randomization of "t9" places the +// "a" element at the end of the record. When that happens, the clang complains +// about excessive initializers, which is confusing, because there aren't +// excessive initializers. It should instead complain about using a +// non-designated initializer on a raqndomized struct. + // Initializing a randomized structure requires a designated initializer, // otherwise the element ordering will be off. The only exceptions to this rule // are: _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
