On 28/10/2019 21:43, Luc Van Oostenryck wrote:
> Sparse is universal in the sense that the same executable can
> be used for all architectures. For this, most arch-specific
> setting can be set with an option and the default values
> are taken from the host machine.
>
> This is working nicely for native targets. However, for cross-
> compilation, while seeming to work relatively well (thanks to
> the kernel build system using -m32/-m64 for all archs, for example)
> things can never work 100% correctly. For example, in the case
> an X86-64 host machine is used for an ARM target, the kernel
> build system will call sparse with -m32, Sparse will 'autodetect'
> the target arch as i386 (x86-64 + -m32) and will then predefine
> the macro __i386__. Most of the time this is not a problem (at
> least for the kernel) unless, of course, if the code contains
> something like:
> #ifdef __i386__
> ...
> #elif __arm__
> ...
>
> So, add an option --arch=<arch> to specify the target architecture.
> The native arch is still used if no such flag is given.
How does this interact with the cgcc --target=<spec> and the
(otherwise) guessing of the 'native' specs?
>
> Reported-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
> ---
> lib.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> sparse.1 | 8 +++++++
> 2 files changed, 76 insertions(+)
>
> diff --git a/lib.c b/lib.c
> index 75a4f9870..353d19100 100644
> --- a/lib.c
> +++ b/lib.c
> @@ -1044,6 +1044,73 @@ static char **handle_switch_x(char *arg, char **next)
> }
>
>
> +static char **handle_arch(char *arg, char **next)
> +{
> + static const struct arch {
> + const char *name;
> + int mach;
> + int bits;
> + } archs[] = {
> + { "aarch64", MACH_ARM64, 64 },
> + { "arm64", MACH_ARM64, 64 },
> + { "arm", MACH_ARM, 32 },
> + { "i386", MACH_I386, 32 },
> + { "m68k", MACH_M68K, 32 },
> + { "mips", MACH_MIPS64 },
> + { "powerpc", MACH_PPC64 },
> + { "ppc", MACH_PPC64 },
> + { "riscv", MACH_RISCV64 },
I would rather these were explicitly set to 0.
> + { "s390", MACH_S390X, 64 },
> + { "s390x", MACH_S390X, 64 },
> + { "sparc", MACH_MIPS64 },
Er, I suppose this should be MACH_SPARC64, right? (also 0 init).
> + { "x86_64", MACH_X86_64, 64 },
> + { "x86-64", MACH_X86_64, 64 },
> + { "x86", MACH_X86_64 },
(also 0 init).
> + { NULL },
> + };
> + const struct arch *p;
> +
> + if (*arg++ != '=')
> + die("missing argument for --arch option");
> +
> + for (p = &archs[0]; p->name; p++) {
> + size_t len = strlen(p->name);
> + if (strncmp(p->name, arg, len) == 0) {
> + const char *suf = arg + len;
> + int bits = p->bits;
> +
> + arch_mach = p->mach;
> + if (bits == 0) {
> + // guess the size of the architecture
> + if (!strcmp(suf, "")) {
> + if (arch_m64 == ARCH_LP32)
> + bits = 32;
> + else
> + bits = 64;
So, this is a 50-50 bet. ;-)
ATB,
Ramsay Jones
> + } else if (!strcmp(suf, "64")) {
> + bits = 64;
> + } else if (!strcmp(suf, "32")) {
> + bits = 32;
> + } else {
> + die("invalid architecture: %s", arg);
> + }
> + if (bits == 32)
> + arch_mach -= 1;
> + } else {
> + if (strcmp(suf, ""))
> + die("invalid architecture: %s", arg);
> + }
> + if (p->bits == 32)
> + arch_m64 = ARCH_LP32;
> + else if (p->bits == 64)
> + arch_m64 = ARCH_LP64;
> + break;
> + }
> + }
> +
> + return next;
> +}
> +
> static char **handle_version(char *arg, char **next)
> {
> printf("%s\n", SPARSE_VERSION);
> @@ -1076,6 +1143,7 @@ struct switches {
> static char **handle_long_options(char *arg, char **next)
> {
> static struct switches cmd[] = {
> + { "arch", handle_arch, 1 },
> { "param", handle_param, 1 },
> { "version", handle_version },
> { NULL, NULL }
> diff --git a/sparse.1 b/sparse.1
> index beb484423..be38f6883 100644
> --- a/sparse.1
> +++ b/sparse.1
> @@ -423,6 +423,14 @@ Sparse does not issue these warnings by default.
> .
> .SH MISC OPTIONS
> .TP
> +.B \-\-arch=\fIARCH\fR
> +Specify the target architecture.
> +For architectures having both a 32-bit and a 64-bit variant (mips, powerpc,
> +riscv & sparc) the architecture name can be suffixed with \fI32\fR or \fI64\fR.
> +
> +The default architecture & size is the one of the machine used to build Sparse.
> +.
> +.TP
> .B \-gcc-base-dir \fIdir\fR
> Look for compiler-provided system headers in \fIdir\fR/include/ and \fIdir\fR/include-fixed/.
> .
>
