nickdesaulniers abandoned this revision. nickdesaulniers marked 2 inline comments as done. nickdesaulniers added a comment.
Merged into https://reviews.llvm.org/D150892. ================ Comment at: clang/lib/AST/ExprConstant.cpp:11737 bool Ret = HandleSizeof(Info, ExprLoc, Ty, Result); if (Ty->isStructureType() && Ty->getAsStructureType()->getDecl()->hasFlexibleArrayMember()) { ---------------- efriedma wrote: > nickdesaulniers wrote: > > efriedma wrote: > > > For the second call to CheckHandleSizeof (line 11791), is the type of > > > consistent with the type of the variable? If Ty refers to a field, I'm > > > not sure it makes sense to call getFlexibleArrayInitChars(). Something > > > along the lines of "struct Z { struct A { int x, y[]; } z; int a; };" > > Can such an object even be initialized? > > ``` > > cat /tmp/x.c > > struct Z { struct A { int x, y[]; } z; int a; }; > > > > static struct Z my_z = { > > .z = { > > .x = 42, > > .y = { > > 0, 1, 2, > > }, > > }, > > .a = 42, > > }; > > > > unsigned long foo (void) { > > return __builtin_object_size(&my_z, 1); > > } > > $ clang -O2 /tmp/x.c -S -o - > > /tmp/x.c:1:37: warning: field 'z' with variable sized type 'struct A' not > > at the end of a struct or class is a GNU extension > > [-Wgnu-variable-sized-type-not-at-end] > > struct Z { struct A { int x, y[]; } z; int a; }; > > ^ > > /tmp/x.c:6:10: error: initialization of flexible array member is not allowed > > .y = { > > ^ > > /tmp/x.c:1:30: note: initialized flexible array member 'y' is here > > struct Z { struct A { int x, y[]; } z; int a; }; > > ^ > > 1 warning and 1 error generated. > > ``` > > or did you have something else in mind? > I was thinking something more along the lines of > > ``` > struct Z { struct A { int x, y[]; } z; int a; int b[]; }; > > static struct Z my_z = { .b = {1,2,3} }; > > unsigned long foo (void) { > return __builtin_object_size(&my_z.z, 1); > } > ``` > > The idea being that you're adding the length of the flexible member even > though the caller isn't trying to ask about it. Ah, thanks! You're right, I didn't understand what was meant by "most derived type." I've fixed this up in the re-opened https://reviews.llvm.org/D150892. PTAL. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D151148/new/ https://reviews.llvm.org/D151148 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
