On Tue, Apr 12, 2022 at 12:27:34PM +0200, Jan Beulich wrote:
> While future gas versions will allow line number information to be
> generated for all instances of .irp and alike [1][2], the same isn't
> true (nor immediately intended) for .macro [3]. Hence macros, when they
> do more than just invoke another macro or issue an individual insn, want
> to have .line directives (in header files also .file ones) in place.
>
> Signed-off-by: Jan Beulich <[email protected]>
>
> [1]
> https://sourceware.org/git?p=binutils-gdb.git;a=commitdiff;h=7992631e8c0b0e711fbaba991348ef6f6e583725
> [2]
> https://sourceware.org/git?p=binutils-gdb.git;a=commitdiff;h=2ee1792bec225ea19c71095cee5a3a9ae6df7c59
> [3]
> https://sourceware.org/git?p=binutils-gdb.git;a=commitdiff;h=6d1ace6861e999361b30d1bc27459ab8094e0d4a
> ---
> Using .file has the perhaps undesirable side effect of generating a fair
> amount of (all identical) STT_FILE entries in the symbol table. We also
> can't use the supposedly assembler-internal (and hence undocumented)
> .appfile anymore, as it was removed [4]. Note that .linefile (also
> internal/undocumented) as well as the "# <line> <file>" constructs the
> compiler emits, leading to .linefile insertion by the assembler, aren't
> of use anyway as these are processed and purged when processing .macro
> [3].
>
> [4]
> https://sourceware.org/git?p=binutils-gdb.git;a=commitdiff;h=c39e89c3aaa3a6790f85e80f2da5022bc4bce38b
>
> --- a/xen/arch/x86/include/asm/spec_ctrl_asm.h
> +++ b/xen/arch/x86/include/asm/spec_ctrl_asm.h
> @@ -24,6 +24,8 @@
> #include <asm/msr-index.h>
> #include <asm/spec_ctrl.h>
>
> +#define FILE_AND_LINE .file __FILE__; .line __LINE__
Seeing as this seems to get added to all macros below, I guess you did
consider (and discarded) introducing a preprocessor macro do to the
asm macro definitons:
#define DECLARE_MACRO(n, ...) \
.macro n __VA_ARGS__ \
.file __FILE__; .line __LINE__
Thanks, Roger.
