On Fri, 28 Nov 2025 15:47:04 GMT, Matthias Baesken <[email protected]> wrote:

> When building the recent mainline JDK (26), I see the following warning 
> messages:
> 
> warning: (arm64) /tmp/lto.o unable to open object file: No such file or 
> directory
> warning: no debug symbols in executable (-arch arm64)
> 
> 
> The build completes normally even with these warnings.
> I am on macos aarch64, but I see the same warning on macos x64 and aarch64 in 
> our CI.
> Seems we miss a linker flag for libs built with lto (libsplashscreen), 
> because the Apple linker has the following issue
> 
> https://clang.llvm.org/docs/CommandGuide/clang.html
> Note
> 
> `
> On Darwin, when using 
> [-flto](https://clang.llvm.org/docs/CommandGuide/clang.html#cmdoption-flto) 
> along with 
> [-g](https://clang.llvm.org/docs/CommandGuide/clang.html#cmdoption-g) and 
> compiling and linking in separate steps, you also need to pass 
> -Wl,-object_path_lto,<lto-filename>.o at the linking step to instruct the 
> ld64 linker not to delete the temporary object file generated during Link 
> Time Optimization (this flag is automatically passed to the linker by Clang 
> if compilation and linking are done in a single step). This allows debugging 
> the executable as well as generating the .dSYM bundle using dsymutil(1).`

This pull request has now been integrated.

Changeset: 317daa3c
Author:    Matthias Baesken <[email protected]>
URL:       
https://git.openjdk.org/jdk/commit/317daa3c004fbb1738e0af6acfbaf50c403c8230
Stats:     5 lines in 1 file changed: 5 ins; 0 del; 0 mod

8372643: Warning message on macos when building the JDK - (arm64) /tmp/lto.o 
unable to open object file: No such file or directory

Reviewed-by: erikj

-------------

PR: https://git.openjdk.org/jdk/pull/28559

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