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[gcn] mkoffload.cc: Print fatal error if -march has no multilib but generic has

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Assume that a distro has configured, e.g., a gfx9-generic multilib but not
for gfx902. In that case, mkoffload would fail to link with "error:
incompatible mach".  With this commit, an error is printed suggesting to try
the associated generic architecture instead.  The behavior is unchanged if
there is a multilib available for the specific ISA or when there is also no
multilib for the generic ICA.

Note: The build of generic multilibs are currently not enabled by default;
they also require the linker/assembler of LLVM 19 or newer and, in particular,
for the execution a future ROCm release. (The next one? In any case, 6.3.2
does not support generic ISAs, yet.)

gcc/ChangeLog:

	* config/gcn/mkoffload.cc (enum elf_arch_code): Add
	EF_AMDGPU_MACH_AMDGCN_NONE.
	(elf_arch): Use enum elf_arch_code as type.
	(tool_cleanup): Silence warning by removing tailing '.' from error.
	(get_arch_name): Return enum elf_arch_code.
	(check_for_missing_lib): New; print fatal error if the multilib
	is not available but it is for the associate generic ISA.
	(main): Call it.
This commit is contained in:
Tobias Burnus 2025-02-10 18:24:34 +01:00
parent 7037fdf6bd
commit 4ce8ad684b
1 changed files with 94 additions and 7 deletions
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101
gcc/config/gcn/mkoffload.cc
View file

@ -53,6 +53,7 @@
/* Extract the EF_AMDGPU_MACH_AMDGCN_GFXnnn from the def file. */
enum elf_arch_code {
EF_AMDGPU_MACH_AMDGCN_NONE = -1, /* For generic handling. */
#define GCN_DEVICE(name, NAME, ELF_ARCH, ...) \
EF_AMDGPU_MACH_AMDGCN_ ## NAME = ELF_ARCH,
#include "gcn-devices.def"
@ -135,9 +136,8 @@ static struct obstack files_to_cleanup;
enum offload_abi offload_abi = OFFLOAD_ABI_UNSET;
const char *offload_abi_host_opts = NULL;
uint32_t elf_arch = EF_AMDGPU_MACH_AMDGCN_GFX900; // Default GPU architecture.
enum elf_arch_code elf_arch = EF_AMDGPU_MACH_AMDGCN_GFX900; // Default GPU architecture.
uint32_t elf_flags = EF_AMDGPU_FEATURE_SRAMECC_UNSUPPORTED_V4;
static int gcn_stack_size = 0; /* Zero means use default. */
/* Delete tempfiles. */
@ -782,7 +782,7 @@ compile_native (const char *infile, const char *outfile, const char *compiler,
obstack_ptr_grow (&argv_obstack, ".c");
if (!offload_abi_host_opts)
fatal_error (input_location,
"%<-foffload-abi-host-opts%> not specified.");
"%<-foffload-abi-host-opts%> not specified");
obstack_ptr_grow (&argv_obstack, offload_abi_host_opts);
obstack_ptr_grow (&argv_obstack, infile);
obstack_ptr_grow (&argv_obstack, "-c");
@ -796,16 +796,15 @@ compile_native (const char *infile, const char *outfile, const char *compiler,
obstack_free (&argv_obstack, NULL);
}
static int
static enum elf_arch_code
get_arch (const char *str, const char *with_arch_str)
{
/* Use the def file to map the name to the elf_arch_code. */
if (!str) ;
#define GCN_DEVICE(name, NAME, ELF, ...) \
else if (strcmp (str, #name) == 0) \
return ELF;
return (enum elf_arch_code) ELF;
#include "gcn-devices.def"
#undef GCN_DEVICE
/* else */
error ("unrecognized argument in option %<-march=%s%>", str);
@ -839,7 +838,91 @@ get_arch (const char *str, const char *with_arch_str)
exit (FATAL_EXIT_CODE);
return 0;
return EF_AMDGPU_MACH_AMDGCN_NONE;
}
static const char*
get_arch_name (enum elf_arch_code arch_code)
{
switch (arch_code)
{
#define GCN_DEVICE(name, NAME, ELF, ...) \
case EF_AMDGPU_MACH_AMDGCN_ ## NAME: \
return #name;
#include "../../gcc/config/gcn/gcn-devices.def"
default: return NULL;
}
}
/* If an generic arch exists and for the chosen arch no (multi)lib is
available, print a fatal error - and suggest to compile for the generic
version instead. */
static void
check_for_missing_lib (enum elf_arch_code elf_arch,
enum elf_arch_code default_arch)
{
enum elf_arch_code generic_arch;
switch (elf_arch)
{
#define GCN_DEVICE(name, NAME, ELF, ISA, XNACK, SRAM, WAVE64, CU, \
MAX_ISA_VGPRS, GEN_VER, ARCH_FAM, GEN_MACH, ...) \
case EF_AMDGPU_MACH_AMDGCN_ ## NAME: \
generic_arch = EF_AMDGPU_MACH_AMDGCN_ ## GEN_MACH; break;
#include "../../gcc/config/gcn/gcn-devices.def"
default: generic_arch = EF_AMDGPU_MACH_AMDGCN_NONE;
}
/* If not generic or the default arch, the library version exists. */
if (generic_arch == EF_AMDGPU_MACH_AMDGCN_NONE || elf_arch == default_arch)
return;
/* Search gcn_arch in the multilib config, which might look like
"march=gfx900/march=gfx906". */
const char *p = multilib_options;
const char *q = NULL;
const char *isa_name = get_arch_name (elf_arch);
while ((q = strstr (p, isa_name)) != NULL)
{
if (multilib_options + strlen ("march=") <= q
&& startswith (&q[-strlen ("march=")], "march="))
{
const char r = q[strlen (isa_name)];
if (r != '\0' && r != '/')
continue;
break;
}
p++;
}
/* Specified -march= exists in the multilib. */
if (q != NULL)
return;
/* If no lib, try to find one for the generic arch. */
const char *gen_name = get_arch_name (generic_arch);
if (generic_arch != default_arch)
{
p = multilib_options;
while ((q = strstr (p, gen_name)) != NULL)
{
if (multilib_options + strlen ("march=") <= q
&& startswith (&q[-strlen ("march=")], "march="))
{
const char r = q[strlen (gen_name)];
if (r != '\0' && r != '/')
continue;
break;
}
p++;
}
if (q == NULL)
return;
}
fatal_error (UNKNOWN_LOCATION,
"GCC was built without library support for %<-march=%s%>; "
"consider compiling for the associated generic architecture "
"%<-march=%s%> instead", isa_name, gen_name);
}
int
@ -864,6 +947,7 @@ main (int argc, char **argv)
elf_arch = get_arch (configure_default_options[0].value, NULL);
break;
}
enum elf_arch_code default_arch = elf_arch;
obstack_init (&files_to_cleanup);
if (atexit (mkoffload_cleanup) != 0)
@ -998,6 +1082,8 @@ main (int argc, char **argv)
}
}
check_for_missing_lib (elf_arch, default_arch);
if (!(fopenacc ^ fopenmp))
fatal_error (input_location,
"either %<-fopenacc%> or %<-fopenmp%> must be set");
@ -1056,6 +1142,7 @@ main (int argc, char **argv)
case ELF: if (GEN_VER) SET_GENERIC_VERSION (elf_flags, GEN_VER); break;
#include "gcn-devices.def"
#undef GCN_DEVICE
case EF_AMDGPU_MACH_AMDGCN_NONE: gcc_unreachable ();
}
/* Build arguments for compiler pass. */