Ping for the middle-end change approval. And an update on the status of the patch set:
******Approval status: All C FE changes have been approved. ******Review status: All Middle-end changes have been reviewed by Sid, no remaining issue. Okay for GCC15? thanks. Qing > On Apr 12, 2024, at 09:54, Qing Zhao <qing.z...@oracle.com> wrote: > > Hi, > > This is the 9th version of the patch. > > Compare with the 8th version, the difference are: > > updates per Joseph's comments: > > 1. in C FE, add checking for counted_by attribute for the new multiple > definitions of the same tag for C23 in the routine > "tagged_types_tu_compatible_p". > Add a new testing case flex-array-counted-by-8.c for this. > This is for Patch 1; > > 2. two minor typo fixes in c-typeck.cc. > This is for Patch 2; > > Approval status: > > Patch 2's C FE change has been approved with minor typo fixes (the above 2); > Patch 4 has been approved; > Patch 5's C FE change has been approved; > > Review status: > > Patch 3, Patch 2 and Patch 5's Middle-end change have been review by Sid, > No issue. > > More review needed: > > Patch 1's new change to C FE (the above 1); > Patch 2, 3 and 5's middle-end change need to be approved > > The 8th version is here: > https://gcc.gnu.org/pipermail/gcc-patches/2024-March/648559.html > https://gcc.gnu.org/pipermail/gcc-patches/2024-March/648560.html > https://gcc.gnu.org/pipermail/gcc-patches/2024-March/648561.html > https://gcc.gnu.org/pipermail/gcc-patches/2024-March/648562.html > https://gcc.gnu.org/pipermail/gcc-patches/2024-March/648563.html > > It based on the following original proposal: > > https://gcc.gnu.org/pipermail/gcc-patches/2023-November/635884.html > Represent the missing dependence for the "counted_by" attribute and its > consumers > > ******The summary of the proposal is: > > * Add a new internal function ".ACCESS_WITH_SIZE" to carry the size > information for every reference to a FAM field; > * In C FE, Replace every reference to a FAM field whose TYPE has the > "counted_by" attribute with the new internal function ".ACCESS_WITH_SIZE"; > * In every consumer of the size information, for example, BDOS or array bound > sanitizer, query the size information or ACCESS_MODE information from the new > internal function; > * When expansing to RTL, replace the internal function with the actual > reference to the FAM field; > * Some adjustment to ipa alias analysis, and other SSA passes to mitigate the > impact to the optimizer and code generation. > > > ******The new internal function > > .ACCESS_WITH_SIZE (REF_TO_OBJ, REF_TO_SIZE, CLASS_OF_SIZE, TYPE_OF_SIZE, > ACCESS_MODE, TYPE_OF_REF) > > INTERNAL_FN (ACCESS_WITH_SIZE, ECF_LEAF | ECF_NOTHROW, NULL) > > which returns the "REF_TO_OBJ" same as the 1st argument; > > Both the return type and the type of the first argument of this function have > been converted from the incomplete array type to the corresponding pointer > type. > > The call to .ACCESS_WITH_SIZE is wrapped with an INDIRECT_REF, whose type is > the original imcomplete array type. > > Please see the following link for why: > https://gcc.gnu.org/pipermail/gcc-patches/2023-November/638793.html > https://gcc.gnu.org/pipermail/gcc-patches/2023-December/639605.html > > 1st argument "REF_TO_OBJ": The reference to the object; > 2nd argument "REF_TO_SIZE": The reference to the size of the object, > 3rd argument "CLASS_OF_SIZE": The size referenced by the REF_TO_SIZE > represents > 0: the number of bytes; > 1: the number of the elements of the object type; > 4th argument "TYPE_OF_SIZE": A constant 0 with the TYPE of the object > refed by REF_TO_SIZE > 5th argument "ACCESS_MODE": > -1: Unknown access semantics > 0: none > 1: read_only > 2: write_only > 3: read_write > 6th argument "TYPE_OF_REF": A constant 0 with the pointer TYPE to > to the original flexible array type. > > ****** The Patch sets included: > > 1. Provide counted_by attribute to flexible array member field; > which includes: > * "counted_by" attribute documentation; > * C FE handling of the new attribute; > syntax checking, error reporting; > * testing cases; > > 2. Convert "counted_by" attribute to/from .ACCESS_WITH_SIZE. > which includes: > * The definition of the new internal function .ACCESS_WITH_SIZE in > internal-fn.def. > * C FE converts every reference to a FAM with "counted_by" attribute to > a call to the internal function .ACCESS_WITH_SIZE. > (build_component_ref in c_typeck.cc) > This includes the case when the object is statically allocated and > initialized. > In order to make this working, we should update > initializer_constant_valid_p_1 and output_constant in varasm.cc to include > calls to .ACCESS_WITH_SIZE. > > However, for the reference inside "offsetof", ignore the "counted_by" > attribute since it's not useful at all. (c_parser_postfix_expression in > c/c-parser.cc) > In addtion to "offsetof", for the reference inside operator "typeof" and > "alignof", we ignore counted_by attribute too. > When building ADDR_EXPR for the .ACCESS_WITH_SIZE in C FE, > replace the call with its first argument. > > * Convert every call to .ACCESS_WITH_SIZE to its first argument. > (expand_ACCESS_WITH_SIZE in internal-fn.cc) > * adjust alias analysis to exclude the new internal from clobbering > anything. > (ref_maybe_used_by_call_p_1 and call_may_clobber_ref_p_1 in > tree-ssa-alias.cc) > * adjust dead code elimination to eliminate the call to > .ACCESS_WITH_SIZE when > it's LHS is eliminated as dead code. > (eliminate_unnecessary_stmts in tree-ssa-dce.cc) > * Provide the utility routines to check the call is .ACCESS_WITH_SIZE and > get the reference from the call to .ACCESS_WITH_SIZE. > (is_access_with_size_p and get_ref_from_access_with_size in tree.cc) > * testing cases. (for offsetof, static initialization, generation of > calls to > .ACCESS_WITH_SIZE, code runs correctly after calls to > .ACCESS_WITH_SIZE are > converted back) > > 3. Use the .ACCESS_WITH_SIZE in builtin object size (sub-object only) > which includes: > * use the size info of the .ACCESS_WITH_SIZE for sub-object. > * when the size is a negative integer, treat it as zero. > * testing cases. > > 4 Use the .ACCESS_WITH_SIZE in bound sanitizer > which includes: > * Instrument array_ref with a call to .ACCESS_WITH_SIZE for bound > sanitizer. > * when the size is a negative integer, treat it as zero. > * testing cases. > > 5. Add the 6th argument to .ACCESS_WITH_SIZE to carry the TYPE of the > flexible array. > which includes: > * Add the 6th argument to .ACCESS_WITH_SIZE. > * use the type of the 6th argument of the routine in tree-object-size.cc > * testing case. > > ******Remaining works: > > 6 Improve __bdos to use the counted_by info in whole-object size for the > structure with FAM. > 7 Emit warnings when the user breaks the requirments for the new counted_by > attribute > compilation time: -Wcounted-by > run time: -fsanitizer=counted-by > * The initialization to the size field should be done before the first > reference to the FAM field. > * the array has at least # of elements specified by the size field all > the time during the program. > > I have bootstrapped and regression tested on both x86 and aarch64, no issue. > > Let me know your comments. > > thanks. > > Qing
