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* [gcc r13-2566] nvptx: libgomp+mkoffload.cc: Prepare for reverse offload fn lookup
@ 2022-09-09 15:58 Tobias Burnus
0 siblings, 0 replies; only message in thread
From: Tobias Burnus @ 2022-09-09 15:58 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:50be486dff4ea2676ed022e9524ef190b92ae2b1
commit r13-2566-g50be486dff4ea2676ed022e9524ef190b92ae2b1
Author: Tobias Burnus <tobias@codesourcery.com>
Date: Fri Sep 9 17:58:02 2022 +0200
nvptx: libgomp+mkoffload.cc: Prepare for reverse offload fn lookup
Add support to nvptx for reverse lookup of function name to prepare for
'omp target device(ancestor:1)'.
gcc/ChangeLog:
* config/nvptx/mkoffload.cc (struct id_map): Add 'dim' member.
(record_id): Store func name without quotes, store dim separately.
(process): For GOMP_REQUIRES_REVERSE_OFFLOAD, check that -march is
at least sm_35, create '$offload_func_table' global array and init
with reverse-offload function addresses.
* config/nvptx/nvptx.cc (write_fn_proto_1, write_fn_proto): New
force_public attribute to force .visible.
(nvptx_declare_function_name): For "omp target
device_ancestor_nohost" attribut, force .visible/TREE_PUBLIC.
libgomp/ChangeLog:
* plugin/plugin-nvptx.c (GOMP_OFFLOAD_load_image): Read offload
function address table '$offload_func_table' if rev_fn_table
is not NULL.
Diff:
---
gcc/config/nvptx/mkoffload.cc | 119 ++++++++++++++++++++++++++++++++++++++++--
gcc/config/nvptx/nvptx.cc | 20 ++++---
libgomp/plugin/plugin-nvptx.c | 19 ++++++-
3 files changed, 145 insertions(+), 13 deletions(-)
diff --git a/gcc/config/nvptx/mkoffload.cc b/gcc/config/nvptx/mkoffload.cc
index 3eea0a8f138..834b2059aac 100644
--- a/gcc/config/nvptx/mkoffload.cc
+++ b/gcc/config/nvptx/mkoffload.cc
@@ -47,6 +47,7 @@ struct id_map
{
id_map *next;
char *ptx_name;
+ char *dim;
};
static id_map *func_ids, **funcs_tail = &func_ids;
@@ -108,8 +109,11 @@ xputenv (const char *string)
static void
record_id (const char *p1, id_map ***where)
{
- const char *end = strchr (p1, '\n');
- if (!end)
+ gcc_assert (p1[0] == '"');
+ p1++;
+ const char *end = strchr (p1, '"');
+ const char *end2 = strchr (p1, '\n');
+ if (!end || !end2 || end >= end2)
fatal_error (input_location, "malformed ptx file");
id_map *v = XNEW (id_map);
@@ -117,6 +121,16 @@ record_id (const char *p1, id_map ***where)
v->ptx_name = XNEWVEC (char, len + 1);
memcpy (v->ptx_name, p1, len);
v->ptx_name[len] = '\0';
+ p1 = end + 1;
+ if (*end != '\n')
+ {
+ len = end2 - p1;
+ v->dim = XNEWVEC (char, len + 1);
+ memcpy (v->dim, p1, len);
+ v->dim[len] = '\0';
+ }
+ else
+ v->dim = NULL;
v->next = NULL;
id_map **tail = *where;
*tail = v;
@@ -242,6 +256,10 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
id_map const *id;
unsigned obj_count = 0;
unsigned ix;
+ const char *sm_ver = NULL, *version = NULL;
+ const char *sm_ver2 = NULL, *version2 = NULL;
+ size_t file_cnt = 0;
+ size_t *file_idx = XALLOCAVEC (size_t, len);
fprintf (out, "#include <stdint.h>\n\n");
@@ -250,6 +268,8 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
for (size_t i = 0; i != len;)
{
char c;
+ bool output_fn_ptr = false;
+ file_idx[file_cnt++] = i;
fprintf (out, "static const char ptx_code_%u[] =\n\t\"", obj_count++);
while ((c = input[i++]))
@@ -261,6 +281,16 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
case '\n':
fprintf (out, "\\n\"\n\t\"");
/* Look for mappings on subsequent lines. */
+ if (UNLIKELY (startswith (input + i, ".target sm_")))
+ {
+ sm_ver = input + i + strlen (".target sm_");
+ continue;
+ }
+ if (UNLIKELY (startswith (input + i, ".version ")))
+ {
+ version = input + i + strlen (".version ");
+ continue;
+ }
while (startswith (input + i, "//:"))
{
i += 3;
@@ -268,7 +298,10 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
if (startswith (input + i, "VAR_MAP "))
record_id (input + i + 8, &vars_tail);
else if (startswith (input + i, "FUNC_MAP "))
- record_id (input + i + 9, &funcs_tail);
+ {
+ output_fn_ptr = true;
+ record_id (input + i + 9, &funcs_tail);
+ }
else
abort ();
/* Skip to next line. */
@@ -286,6 +319,81 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
putc (c, out);
}
fprintf (out, "\";\n\n");
+ if (output_fn_ptr
+ && (omp_requires & GOMP_REQUIRES_REVERSE_OFFLOAD) != 0)
+ {
+ if (sm_ver && sm_ver[0] == '3' && sm_ver[1] == '0'
+ && sm_ver[2] == '\n')
+ fatal_error (input_location,
+ "%<omp requires reverse_offload%> requires at least "
+ "%<sm_35%> for %<-misa=%>");
+ sm_ver2 = sm_ver;
+ version2 = version;
+ }
+ }
+
+ /* Create function-pointer array, required for reverse
+ offload function-pointer lookup. */
+
+ if (func_ids && (omp_requires & GOMP_REQUIRES_REVERSE_OFFLOAD) != 0)
+ {
+ const char needle[] = "// BEGIN GLOBAL FUNCTION DECL: ";
+ fprintf (out, "static const char ptx_code_%u[] =\n", obj_count++);
+ fprintf (out, "\t\".version ");
+ for (size_t i = 0; version2[i] != '\0' && version2[i] != '\n'; i++)
+ fputc (version2[i], out);
+ fprintf (out, "\"\n\t\".target sm_");
+ for (size_t i = 0; version2[i] != '\0' && sm_ver2[i] != '\n'; i++)
+ fputc (sm_ver2[i], out);
+ fprintf (out, "\"\n\t\".file 1 \\\"<dummy>\\\"\"\n");
+
+ size_t fidx = 0;
+ for (id = func_ids; id; id = id->next)
+ {
+ /* Only 'nohost' functions are needed - use NULL for the rest.
+ Alternatively, besides searching for 'BEGIN FUNCTION DECL',
+ checking for '.visible .entry ' + id->ptx_name would be
+ required. */
+ if (!endswith (id->ptx_name, "$nohost"))
+ continue;
+ fprintf (out, "\t\".extern ");
+ const char *p = input + file_idx[fidx];
+ while (true)
+ {
+ p = strstr (p, needle);
+ if (!p)
+ {
+ fidx++;
+ if (fidx >= file_cnt)
+ break;
+ p = input + file_idx[fidx];
+ continue;
+ }
+ p += strlen (needle);
+ if (!startswith (p, id->ptx_name))
+ continue;
+ p += strlen (id->ptx_name);
+ if (*p != '\n')
+ continue;
+ p++;
+ gcc_assert (startswith (p, ".visible "));
+ p += strlen (".visible ");
+ for (; *p != '\0' && *p != '\n'; p++)
+ fputc (*p, out);
+ break;
+ }
+ fprintf (out, "\"\n");
+ if (fidx == file_cnt)
+ fatal_error (input_location,
+ "Cannot find function declaration for %qs",
+ id->ptx_name);
+ }
+ fprintf (out, "\t\".visible .global .align 8 .u64 "
+ "$offload_func_table[] = {");
+ for (comma = "", id = func_ids; id; comma = ",", id = id->next)
+ fprintf (out, "%s\"\n\t\t\"%s", comma,
+ endswith (id->ptx_name, "$nohost") ? id->ptx_name : "0");
+ fprintf (out, "};\\n\";\n\n");
}
/* Dump out array of pointers to ptx object strings. */
@@ -300,7 +408,7 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
/* Dump out variable idents. */
fprintf (out, "static const char *const var_mappings[] = {");
for (comma = "", id = var_ids; id; comma = ",", id = id->next)
- fprintf (out, "%s\n\t%s", comma, id->ptx_name);
+ fprintf (out, "%s\n\t\"%s\"", comma, id->ptx_name);
fprintf (out, "\n};\n\n");
/* Dump out function idents. */
@@ -309,7 +417,8 @@ process (FILE *in, FILE *out, uint32_t omp_requires)
" unsigned short dim[%d];\n"
"} func_mappings[] = {\n", GOMP_DIM_MAX);
for (comma = "", id = func_ids; id; comma = ",", id = id->next)
- fprintf (out, "%s\n\t{%s}", comma, id->ptx_name);
+ fprintf (out, "%s\n\t{\"%s\"%s}", comma, id->ptx_name,
+ id->dim ? id->dim : "");
fprintf (out, "\n};\n\n");
fprintf (out,
diff --git a/gcc/config/nvptx/nvptx.cc b/gcc/config/nvptx/nvptx.cc
index 3634a49de3f..49cc6814178 100644
--- a/gcc/config/nvptx/nvptx.cc
+++ b/gcc/config/nvptx/nvptx.cc
@@ -988,15 +988,15 @@ write_var_marker (FILE *file, bool is_defn, bool globalize, const char *name)
static void
write_fn_proto_1 (std::stringstream &s, bool is_defn,
- const char *name, const_tree decl)
+ const char *name, const_tree decl, bool force_public)
{
if (lookup_attribute ("alias", DECL_ATTRIBUTES (decl)) == NULL)
- write_fn_marker (s, is_defn, TREE_PUBLIC (decl), name);
+ write_fn_marker (s, is_defn, TREE_PUBLIC (decl) || force_public, name);
/* PTX declaration. */
if (DECL_EXTERNAL (decl))
s << ".extern ";
- else if (TREE_PUBLIC (decl))
+ else if (TREE_PUBLIC (decl) || force_public)
s << (DECL_WEAK (decl) ? ".weak " : ".visible ");
s << (write_as_kernel (DECL_ATTRIBUTES (decl)) ? ".entry " : ".func ");
@@ -1085,7 +1085,7 @@ write_fn_proto_1 (std::stringstream &s, bool is_defn,
static void
write_fn_proto (std::stringstream &s, bool is_defn,
- const char *name, const_tree decl)
+ const char *name, const_tree decl, bool force_public=false)
{
const char *replacement = nvptx_name_replacement (name);
char *replaced_dots = NULL;
@@ -1102,9 +1102,9 @@ write_fn_proto (std::stringstream &s, bool is_defn,
if (is_defn)
/* Emit a declaration. The PTX assembler gets upset without it. */
- write_fn_proto_1 (s, false, name, decl);
+ write_fn_proto_1 (s, false, name, decl, force_public);
- write_fn_proto_1 (s, is_defn, name, decl);
+ write_fn_proto_1 (s, is_defn, name, decl, force_public);
if (replaced_dots)
XDELETE (replaced_dots);
@@ -1480,7 +1480,13 @@ nvptx_declare_function_name (FILE *file, const char *name, const_tree decl)
tree fntype = TREE_TYPE (decl);
tree result_type = TREE_TYPE (fntype);
int argno = 0;
+ bool force_public = false;
+ /* For reverse-offload 'nohost' functions: In order to be collectable in
+ '$offload_func_table', cf. mkoffload.cc, the function has to be visible. */
+ if (lookup_attribute ("omp target device_ancestor_nohost",
+ DECL_ATTRIBUTES (decl)))
+ force_public = true;
if (lookup_attribute ("omp target entrypoint", DECL_ATTRIBUTES (decl))
&& !lookup_attribute ("oacc function", DECL_ATTRIBUTES (decl)))
{
@@ -1492,7 +1498,7 @@ nvptx_declare_function_name (FILE *file, const char *name, const_tree decl)
/* We construct the initial part of the function into a string
stream, in order to share the prototype writing code. */
std::stringstream s;
- write_fn_proto (s, true, name, decl);
+ write_fn_proto (s, true, name, decl, force_public);
s << "{\n";
bool return_in_mem = write_return_type (s, false, result_type);
diff --git a/libgomp/plugin/plugin-nvptx.c b/libgomp/plugin/plugin-nvptx.c
index 044bb9c09a6..ba6b2298050 100644
--- a/libgomp/plugin/plugin-nvptx.c
+++ b/libgomp/plugin/plugin-nvptx.c
@@ -1273,7 +1273,7 @@ nvptx_set_clocktick (CUmodule module, struct ptx_device *dev)
int
GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
struct addr_pair **target_table,
- uint64_t **rev_fn_table __attribute__((unused)))
+ uint64_t **rev_fn_table)
{
CUmodule module;
const char *const *var_names;
@@ -1375,6 +1375,23 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
/* The variable was not in this image. */
targ_tbl->start = targ_tbl->end = 0;
+ if (rev_fn_table && fn_entries == 0)
+ *rev_fn_table = NULL;
+ else if (rev_fn_table)
+ {
+ CUdeviceptr var;
+ size_t bytes;
+ r = CUDA_CALL_NOCHECK (cuModuleGetGlobal, &var, &bytes, module,
+ "$offload_func_table");
+ if (r != CUDA_SUCCESS)
+ GOMP_PLUGIN_fatal ("cuModuleGetGlobal error: %s", cuda_error (r));
+ assert (bytes == sizeof (uint64_t) * fn_entries);
+ *rev_fn_table = GOMP_PLUGIN_malloc (sizeof (uint64_t) * fn_entries);
+ r = CUDA_CALL_NOCHECK (cuMemcpyDtoH, *rev_fn_table, var, bytes);
+ if (r != CUDA_SUCCESS)
+ GOMP_PLUGIN_fatal ("cuMemcpyDtoH error: %s", cuda_error (r));
+ }
+
nvptx_set_clocktick (module, dev);
return fn_entries + var_entries + other_entries;
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