On Tue, 3 Feb 2026 07:26:57 GMT, Kim Barrett <[email protected]> wrote:
>> Allow conversion warnings in subsets of the code base. By allowing this, we >> can improve the code base in parts, and see that those parts do not regress >> in the future. >> >> My approach to implement this is by adding support to our make system to >> recognise and handle "variable packs". A "variable pack" is a list of quoted >> variable "appendings". It will be picked up by `NamedParamsMacroTemplate` >> and there recognised by the lack of an assignment operator that is always >> used when sending variables to macros today. To support sending lists of >> "variable appendings", the appendings must quote assignment, spaces and >> quotes. This would be cleanest to implement by hex or base64 encode the >> string. However, this is extremely hard to do in make, and I prefer not >> calling the likes of `od` or `base64` to make the code portable and fast. >> >> With this infrastructure I implement a simple recursive utility to find all >> files matching a pattern in a folder; I then transform that list to variable >> assignments that will add compiler warnings for those files. >> >> This approach is extremely flexible. I can for example combine many calls to >> the `overrideFlags` macro with different source directories and different >> patterns. >> >> The macro will expand to something like (depending on compiler): >> `module_file1.cpp_CXXFLAGS+=-Wconversion` >> `module_file2.cpp_CXXFLAGS+=-Wconversion` >> >> this can flexibly be combined with other flags to overlap: >> `module_file2.cpp_CXXFLAGS+=$(SPACE)-Wotherflag` >> `module_file3.cpp_CXXFLAGS+=$(SPACE)-Wotherflag` >> >> (note the overlapping sets of flags `file1 -Wconversion`, `file2 >> -Wconversion -Wotherflag`, `file3 -Wotherflag`) > > make/hotspot/lib/CompileJvm.gmk line 192: > >> 190: abstract_vm_version.cpp_CXXFLAGS := $(CFLAGS_VM_VERSION), \ >> 191: arguments.cpp_CXXFLAGS := $(CFLAGS_VM_VERSION), \ >> 192: $(call >> overrideFlags,$(TOPDIR)/src/hotspot/share/gc/g1,g1ConcurrentMark.cpp,_CXXFLAGS,$(CFLAGS_CONVERSION_WARNINGS)), >> \ > > Does this new mechanism support multiple mappings of source trees to warning > options? If not, this seems too restrictive. But if so, then my earlier > comment about warning ghettos becomes even more of a concern. Multiple, and overlapping regions, with different source directories and different filters. I fully support warning ghettos, I see it as a fantastic opportunity! ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/29523#discussion_r2759329187
