RFR: 8348207: Linux PPC64 PCH build broken after JDK-8347909

[Magnus Ihse Bursie]

On Thu, 23 Jan 2025 12:59:19 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> The Linux PPC64 PCH build was broken after JDK-8347909.
> Build error
> 
> * For target hotspot_variant-server_libjvm_objs_sharedRuntimeTrans.o:
> cc1plus: error: /jdk25_opt/hotspot/variant-server/libjvm/objs/precompiled/precompiled.hpp.gch: created and used with differing settings of '-mpower8-fusion-sign' [-Werror=invalid-pch]
> cc1plus: error: one or more PCH files were found, but they were invalid
> <command-line>: fatal error: precompiled.hpp: No such file or directory
> 
> * For target hotspot_variant-server_libjvm_objs_sharedRuntimeTrig.o:
> cc1plus: error: /jdk25_opt/hotspot/variant-server/libjvm/objs/precompiled/precompiled.hpp.gch: created and used with differing settings of '-mpower8-fusion-sign' [-Werror=invalid-pch]
> cc1plus: error: one or more PCH files were found, but they were invalid
> <command-line>: fatal error: precompiled.hpp: No such file or directory
> 
> 
> There was a mismatch of the build settings of  precompiled.hpp.gch and these 2 compilation units leading to this error;  the PCH build exclusion of these 2 files did not work.

make/hotspot/lib/JvmOverrideFiles.gmk line 61:

> 59:       sharedRuntimeTrig.cpp \
> 60:       sharedRuntimeTrans.cpp \
> 61:       $(OPT_SPEED_SRC) \

Note that OPT_SPEED_SRC contains a rather large set of files. They have previously been compiling using PCH just fine with gcc. I don't think it is motivated to exclude them everywhere, just because gcc on ppc64 has a problem.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23268#discussion_r1927840995