[hsa] Introduce hsakernel function attribute
Martin Jambor
mjambor@suse.cz
Thu Sep 25 23:43:00 GMT 2014
Hi,
in the hsa branch, we currently compile functions with the hsa
attribute to an HSA kernel and when such a function is called, we
translate into a call to libgomp which then feeds the grid and group
sizes (basically the number of threads and how they are structured).
For GPGPU we of course want to hand over also the grid and group sizes
depending on the problem size, so this patch introduces a new
attribute, hsakernel, which means that the grid size is passed in the
last but one actual argument and the group size in the last one. The
attribute is mainly intended to be auto-generated by OMP expansion but
is accessible to users just in case they want to experiment with
generation of HSA code without OMP stuff.
Yes, I am fully aware that this only serves as a proof of concept and
that we will want some better representation of this in the future,
but this will be easy to change once we are dealing with such small
issues like this one.
In the short-term I plan to remove the hsa attribute and perhaps
introduce a hsafunc attribute meaning something like OMP4.0 declare
target, i.e. a function callable from within HSA (and which are
represented differently from kernels in HSAIL).
Bootstrapping only showed there were no warnings, I have tested this
with some later patches on a number of OMP testcases. Committed to
the HSA branch.
Thanks,
Martin
2014-09-26 Martin Jambor <mjambor@suse.cz>
gcc/
* hsa-gen.c (insert_store_range_dim): Make value parameter a tree.
(wrap_hsa): Handle hsakernel functions.
(namespace): Likewise.
gcc/c-family/
* c-common.c (c_common_attribute_table): Add hsakernel attribute.
(handle_hsa_attribute): Make function used and noinline, warn about
hsakernel on functions with fixed number of arguments.
---
gcc/c-family/c-common.c | 11 +++++
gcc/hsa-gen.c | 110 +++++++++++++++++++++++++++++++++++-------------
2 files changed, 92 insertions(+), 29 deletions(-)
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index f92f3d0..0ba16ef 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -639,6 +639,8 @@ const struct attribute_spec c_common_attribute_table[] =
handle_noclone_attribute, false },
{ "hsa", 0, 0, true, false, false,
handle_hsa_attribute, false },
+ { "hsakernel", 0, 0, true, false, false,
+ handle_hsa_attribute, false },
{ "leaf", 0, 0, true, false, false,
handle_leaf_attribute, false },
{ "always_inline", 0, 0, true, false, false,
@@ -6732,8 +6734,17 @@ handle_hsa_attribute (tree *node, tree name,
{
warning (OPT_Wattributes, "%qE attribute ignored", name);
*no_add_attrs = true;
+ return NULL_TREE;
}
+ TREE_USED (*node) = 1;
+ DECL_UNINLINABLE (*node) = 1;
+ if (strcmp ("hsakernel", IDENTIFIER_POINTER (name)) == 0
+ && (TREE_VALUE (tree_last (TYPE_ARG_TYPES (TREE_TYPE (*node))))
+ == void_type_node))
+ warning (OPT_Wattributes, "%qE attribute on a function with fixed number "
+ "of argument makes no sense", name);
+
return NULL_TREE;
}
diff --git a/gcc/hsa-gen.c b/gcc/hsa-gen.c
index 7a0e642..101acb4 100644
--- a/gcc/hsa-gen.c
+++ b/gcc/hsa-gen.c
@@ -2060,22 +2060,19 @@ init_hsa_functions (void)
}
/* Insert before the current statement in GSI a store of VALUE to INDEX of
- array (of type hsa_dim_array_type) FLD_DECL of RANGE_VAR. */
+ array (of type hsa_dim_array_type) FLD_DECL of RANGE_VAR. VALUE must be of
+ type uint32_type_node. */
static void
insert_store_range_dim (gimple_stmt_iterator *gsi, tree range_var,
- tree fld_decl, int index, int value)
+ tree fld_decl, int index, tree value)
{
tree ref = build4 (ARRAY_REF, uint32_type_node,
build3 (COMPONENT_REF, hsa_dim_array_type,
range_var, fld_decl, NULL_TREE),
build_int_cst (integer_type_node, index),
NULL_TREE, NULL_TREE);
- gsi_insert_before (gsi,
- gimple_build_assign (ref,
- build_int_cst (uint32_type_node,
- value)),
- GSI_SAME_STMT);
+ gsi_insert_before (gsi, gimple_build_assign (ref, value), GSI_SAME_STMT);
}
static unsigned int
@@ -2091,13 +2088,16 @@ wrap_hsa (void)
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
if (is_gimple_call (gsi_stmt (gsi))
&& (fndecl = gimple_call_fndecl (gsi_stmt (gsi)))
- && lookup_attribute ("hsa", DECL_ATTRIBUTES (fndecl)))
+ && (lookup_attribute ("hsa", DECL_ATTRIBUTES (fndecl))
+ || lookup_attribute ("hsakernel", DECL_ATTRIBUTES (fndecl))))
{
char *tmpname;
- gimple launch;
+ gimple launch, call_stmt = gsi_stmt (gsi);
vec<constructor_elt, va_gc> *v = NULL;
tree str;
str = build_string_literal (1, "");
+ bool kern_p = lookup_attribute ("hsakernel",
+ DECL_ATTRIBUTES (fndecl));
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, str);
int slen = IDENTIFIER_LENGTH (DECL_ASSEMBLER_NAME (fndecl));
@@ -2108,9 +2108,14 @@ wrap_hsa (void)
str = build_string_literal (slen + 2, tmpname);
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, str);
+ int discard_arguents;
+ int num_args = gimple_call_num_args (call_stmt);
+ if (kern_p)
+ discard_arguents = 2;
+ else
+ discard_arguents = 0;
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
- size_int (gimple_call_num_args
- (gsi_stmt (gsi))));
+ size_int (num_args - discard_arguents));
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, null_pointer_node);
CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, null_pointer_node);
@@ -2120,9 +2125,9 @@ wrap_hsa (void)
char tmp_name[32];
static unsigned int var_id;
ASM_GENERATE_INTERNAL_LABEL (tmp_name, "__hsa_kd", var_id++);
- tree desc = build_decl (gimple_location (gsi_stmt (gsi)),
- VAR_DECL, get_identifier (tmp_name),
- hsa_kernel_desc_type);
+ tree desc = build_decl (gimple_location (call_stmt), VAR_DECL,
+ get_identifier (tmp_name),
+ hsa_kernel_desc_type);
TREE_STATIC (desc) = 1;
TREE_PUBLIC (desc) = 0;
DECL_ARTIFICIAL (desc) = 1;
@@ -2135,31 +2140,77 @@ wrap_hsa (void)
varpool_node::finalize_decl (desc);
desc = build_fold_addr_expr (desc);
+ tree grid_size_1, group_size_1;
+ tree u32_one = build_int_cst (uint32_type_node, 1);
+ if (kern_p)
+ {
+ discard_arguents = 2;
+ int num_args = gimple_call_num_args (call_stmt);
+ if (num_args < 2)
+ {
+ error ("Calls to functions with hsakernel attribute must "
+ "have at least two arguments.");
+ grid_size_1 = group_size_1 = u32_one;
+ }
+ else
+ {
+ grid_size_1 = fold_convert (uint32_type_node,
+ gimple_call_arg (call_stmt,
+ num_args - 2));
+ grid_size_1 = force_gimple_operand_gsi (&gsi, grid_size_1,
+ true, NULL_TREE,
+ true,
+ GSI_SAME_STMT);
+ group_size_1 = fold_convert (uint32_type_node,
+ gimple_call_arg (call_stmt,
+ num_args
+ - 1));
+ group_size_1 = force_gimple_operand_gsi (&gsi, group_size_1,
+ true, NULL_TREE,
+ true,
+ GSI_SAME_STMT);
+ }
+ }
+ else
+ {
+ discard_arguents = 0;
+ grid_size_1 = build_int_cst (uint32_type_node, 256);
+ group_size_1 = build_int_cst (uint32_type_node, 16);
+ }
+
+
/* We fill in range dynamically because later on we'd like to
decide about the values at run time. */
tree range = create_tmp_var (hsa_launch_range_type, "__hsa_range");
tree dimref = build3 (COMPONENT_REF, uint32_type_node,
range, hsa_range_dimnum_decl, NULL_TREE);
- tree u32one = build_int_cst (uint32_type_node, 1);
gsi_insert_before (&gsi,
- gimple_build_assign (dimref, u32one),
+ gimple_build_assign (dimref, u32_one),
GSI_SAME_STMT);
- insert_store_range_dim (&gsi, range, hsa_range_grid_decl, 0, 256);
- insert_store_range_dim (&gsi, range, hsa_range_grid_decl, 1, 1);
- insert_store_range_dim (&gsi, range, hsa_range_grid_decl, 2, 1);
- insert_store_range_dim (&gsi, range, hsa_range_group_decl, 0, 16);
- insert_store_range_dim (&gsi, range, hsa_range_group_decl, 1, 1);
- insert_store_range_dim (&gsi, range, hsa_range_group_decl, 2, 1);
+ insert_store_range_dim (&gsi, range, hsa_range_grid_decl, 0,
+ grid_size_1);
+ insert_store_range_dim (&gsi, range, hsa_range_grid_decl, 1,
+ u32_one);
+ insert_store_range_dim (&gsi, range, hsa_range_grid_decl, 2,
+ u32_one);
+ insert_store_range_dim (&gsi, range, hsa_range_group_decl, 0,
+ group_size_1);
+ insert_store_range_dim (&gsi, range, hsa_range_group_decl, 1,
+ u32_one);
+ insert_store_range_dim (&gsi, range, hsa_range_group_decl, 2,
+ u32_one);
range = build_fold_addr_expr (range);
tree args = create_tmp_var
(build_array_type_nelts (uint64_type_node,
- gimple_call_num_args (gsi_stmt (gsi))),
- NULL);
+ gimple_call_num_args (call_stmt)),
+ NULL);
- for (unsigned i = 0; i < gimple_call_num_args (gsi_stmt (gsi)); i++)
+ for (unsigned i = 0;
+ i < gimple_call_num_args (call_stmt) - discard_arguents;
+ i++)
{
- tree arg = gimple_call_arg (gsi_stmt (gsi), i);
+ tree arg = gimple_call_arg (call_stmt, i);
gimple g;
tree r = build4 (ARRAY_REF, uint64_type_node, args,
@@ -2180,7 +2231,7 @@ wrap_hsa (void)
edges. */
launch = gimple_build_call (hsa_launch_fn, 3, desc, range, args);
gsi_insert_before (&gsi, launch, GSI_SAME_STMT);
- unlink_stmt_vdef (gsi_stmt (gsi));
+ unlink_stmt_vdef (call_stmt);
gsi_remove (&gsi, true);
changed = true;
}
@@ -2229,8 +2280,9 @@ pass_gen_hsail::gate (function *)
unsigned int
pass_gen_hsail::execute (function *)
{
- if (lookup_attribute ("hsa",
- DECL_ATTRIBUTES (current_function_decl)))
+ if (lookup_attribute ("hsa", DECL_ATTRIBUTES (current_function_decl))
+ || lookup_attribute ("hsakernel",
+ DECL_ATTRIBUTES (current_function_decl)))
return generate_hsa ();
else
return wrap_hsa ();
--
1.8.4.5
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