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Nick Desaulniers authored
When debugging LLVM IR, it can be handy for clang to not discard value names used for local variables and parameters. Compare the generated IR. -fdiscard-value-names: define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) { %6 = alloca i64 %7 = alloca %struct.poll_wqueues %8 = alloca [64 x i32] -fno-discard-value-names: define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp, ptr %end_time) { %expire.i = alloca i64 %table.i = alloca %struct.poll_wqueues %stack_fds = alloca [64 x i32] The rule for generating human readable LLVM IR (.ll) is only useful as a debugging feature: $ make LLVM=1 fs/select.ll As Fangrui notes: A LLVM_ENABLE_ASSERTIONS=off build of Clang defaults to -fdiscard-value-names. A LLVM_ENABLE_ASSERTIONS=on build of Clang defaults to -fno-discard-value-names. Explicitly enable -fno-discard-value-names so that the IR always contains value names regardless of whether assertions were enabled or not. Assertions generally are not enabled in releases of clang packaged by distributions. Link: https://github.com/ClangBuiltLinux/linux/issues/1467Reviewed-by:
Nathan Chancellor <nathan@kernel.org> Reviewed-by:
Fangrui Song <maskray@google.com> Signed-off-by:
Nick Desaulniers <ndesaulniers@google.com> Signed-off-by:
Masahiro Yamada <masahiroy@kernel.org>
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