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glsl: Immediately inline built-ins rather than generating calls. 

In the past, we imported the prototypes of built-in functions, generated
calls to those, and waited until link time to resolve the calls and
import the actual code for the built-in functions.

This severely limited our compile-time optimization opportunities: even
trivial functions like dot() were represented as function calls.  We
also had no way of reasoning about those calls; they could have been
1,000 line functions with side-effects for all we knew.

Practically all built-in functions are trivial translations to
ir_expression opcodes, so it makes sense to just generate those inline.
Since we eventually inline all functions anyway, we may as well just do
it for all built-in functions.

There's only one snag: built-in functions that refer to built-in global
variables need those remapped to the variables in the shader being
compiled, rather than the ones in the built-in shader.  Currently,
ftransform() is the only function matching those criteria, so it seemed
easier to just make it a special case.

On Skylake:

total instructions in shared programs: 12023491 -> 12024010 (0.00%)
instructions in affected programs: 77595 -> 78114 (0.67%)
helped: 97
HURT: 309

total cycles in shared programs: 137239044 -> 137295498 (0.04%)
cycles in affected programs: 16714026 -> 16770480 (0.34%)
helped: 4663
HURT: 4923

while these statistics are in the wrong direction, the number of
hurt programs is small (309 / 41282 = 0.75%), and I don't think
anything can be done about it.  A change like this significantly
alters the order in which optimizations are performed.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by; Ian Romanick <ian.d.romanick@intel.com>
This commit is contained in:
Kenneth Graunke 2014-05-30 23:52:22 -07:00
parent 1617f59bc6
commit b04ef3c08a
1 changed files with 22 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
src/compiler/glsl/ast_function.cpp
View File

@ -430,7 +430,8 @@ generate_call(exec_list *instructions, ir_function_signature *sig,
exec_list *actual_parameters,
ir_variable *sub_var,
ir_rvalue *array_idx,
struct _mesa_glsl_parse_state *state)
struct _mesa_glsl_parse_state *state,
bool inline_immediately)
{
void *ctx = state;
exec_list post_call_conversions;
@ -542,6 +543,10 @@ generate_call(exec_list *instructions, ir_function_signature *sig,
ir_call *call = new(ctx) ir_call(sig, deref,
actual_parameters, sub_var, array_idx);
instructions->push_tail(call);
if (inline_immediately) {
call->generate_inline(call);
call->remove();
}
/* Also emit any necessary out-parameter conversions. */
instructions->append_list(&post_call_conversions);
@ -557,19 +562,18 @@ match_function_by_name(const char *name,
exec_list *actual_parameters,
struct _mesa_glsl_parse_state *state)
{
void *ctx = state;
ir_function *f = state->symbols->get_function(name);
ir_function_signature *local_sig = NULL;
ir_function_signature *sig = NULL;
/* Is the function hidden by a record type constructor? */
if (state->symbols->get_type(name))
goto done; /* no match */
return sig; /* no match */
/* Is the function hidden by a variable (impossible in 1.10)? */
if (!state->symbols->separate_function_namespace
&& state->symbols->get_variable(name))
goto done; /* no match */
return sig; /* no match */
if (f != NULL) {
/* In desktop GL, the presence of a user-defined signature hides any
@ -583,31 +587,15 @@ match_function_by_name(const char *name,
sig = local_sig = f->matching_signature(state, actual_parameters,
allow_builtins, &is_exact);
if (is_exact)
goto done;
return sig;
if (!allow_builtins)
goto done;
return sig;
}
/* Local shader has no exact candidates; check the built-ins. */
_mesa_glsl_initialize_builtin_functions();
sig = _mesa_glsl_find_builtin_function(state, name, actual_parameters);
done:
if (sig != NULL) {
/* If the match is from a linked built-in shader, import the
* prototype.
*/
if (sig != local_sig) {
if (f == NULL) {
f = new(ctx) ir_function(name);
state->symbols->add_global_function(f);
emit_function(state, f);
}
sig = sig->clone_prototype(f, NULL);
f->add_signature(sig);
}
}
return sig;
}
@ -2142,6 +2130,16 @@ ast_function_expression::hir(exec_list *instructions,
this->expressions)) {
/* an error has already been emitted */
value = ir_rvalue::error_value(ctx);
} else if (sig->is_builtin() && strcmp(func_name, "ftransform") == 0) {
/* ftransform refers to global variables, and we don't have any code
* for remapping the variable references in the built-in shader.
*/
ir_variable *mvp =
state->symbols->get_variable("gl_ModelViewProjectionMatrix");
ir_variable *vtx = state->symbols->get_variable("gl_Vertex");
value = new(ctx) ir_expression(ir_binop_mul, glsl_type::vec4_type,
new(ctx) ir_dereference_variable(mvp),
new(ctx) ir_dereference_variable(vtx));
} else {
if (state->stage == MESA_SHADER_TESS_CTRL &&
sig->is_builtin() && strcmp(func_name, "barrier") == 0) {
@ -2162,8 +2160,8 @@ ast_function_expression::hir(exec_list *instructions,
}
}
value = generate_call(instructions, sig,
&actual_parameters, sub_var, array_idx, state);
value = generate_call(instructions, sig, &actual_parameters, sub_var,
array_idx, state, sig->is_builtin());
if (!value) {
ir_variable *const tmp = new(ctx) ir_variable(glsl_type::void_type,
"void_var",