Mesa (master): glsl: rework zero initialization

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Module: Mesa
Branch: master
Commit: fa6b22d36a915f27dee576063aead9e2c577f966
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=fa6b22d36a915f27dee576063aead9e2c577f966

Author: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
Date:   Fri Apr 24 17:55:38 2020 +0200

glsl: rework zero initialization

This commit makes zero_init a bitfield of types of variables to zeroinit.

This will allow some flexibility that will be used in the next commit.

Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4607>

---

 src/compiler/glsl/ast_to_hir.cpp         | 13 +++++++++----
 src/compiler/glsl/glsl_parser_extras.cpp |  6 +++++-
 src/compiler/glsl/glsl_parser_extras.h   |  3 ++-
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
index 9cd3af83a48..fb7c2cce924 100644
--- a/src/compiler/glsl/ast_to_hir.cpp
+++ b/src/compiler/glsl/ast_to_hir.cpp
@@ -5265,10 +5265,8 @@ ast_declarator_list::hir(exec_list *instructions,
       apply_layout_qualifier_to_variable(&this->type->qualifier, var, state,
                                          &loc);
 
-      if ((var->data.mode == ir_var_auto || var->data.mode == ir_var_temporary
-           || var->data.mode == ir_var_shader_out)
-          && (var->type->is_numeric() || var->type->is_boolean())
-          && state->zero_init) {
+      if ((state->zero_init & (1u << var->data.mode)) &&
+          (var->type->is_numeric() || var->type->is_boolean())) {
          const ir_constant_data data = { { 0 } };
          var->data.has_initializer = true;
          var->constant_initializer = new(var) ir_constant(var->type, &data);
@@ -5861,6 +5859,13 @@ ast_parameter_declarator::hir(exec_list *instructions,
    apply_type_qualifier_to_variable(& this->type->qualifier, var, state, & loc,
                                     true);
 
+   if (((1u << var->data.mode) & state->zero_init) &&
+       (var->type->is_numeric() || var->type->is_boolean())) {
+         const ir_constant_data data = { { 0 } };
+         var->data.has_initializer = true;
+         var->constant_initializer = new(var) ir_constant(var->type, &data);
+   }
+
    /* From section 4.1.7 of the GLSL 4.40 spec:
     *
     *   "Opaque variables cannot be treated as l-values; hence cannot
diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
index c394f00480a..5b8e5b4c48f 100644
--- a/src/compiler/glsl/glsl_parser_extras.cpp
+++ b/src/compiler/glsl/glsl_parser_extras.cpp
@@ -82,7 +82,11 @@ _mesa_glsl_parse_state::_mesa_glsl_parse_state(struct gl_context *_ctx,
    /* Set default language version and extensions */
    this->language_version = 110;
    this->forced_language_version = ctx->Const.ForceGLSLVersion;
-   this->zero_init = ctx->Const.GLSLZeroInit;
+   if (ctx->Const.GLSLZeroInit == 1) {
+      this->zero_init = (1u << ir_var_auto) | (1u << ir_var_temporary) | (1u << ir_var_shader_out);
+   } else {
+      this->zero_init = 0;
+   }
    this->gl_version = 20;
    this->compat_shader = true;
    this->es_shader = false;
diff --git a/src/compiler/glsl/glsl_parser_extras.h b/src/compiler/glsl/glsl_parser_extras.h
index 49e1f1e2a51..bdc0d9ab827 100644
--- a/src/compiler/glsl/glsl_parser_extras.h
+++ b/src/compiler/glsl/glsl_parser_extras.h
@@ -388,7 +388,8 @@ struct _mesa_glsl_parse_state {
    bool compat_shader;
    unsigned language_version;
    unsigned forced_language_version;
-   bool zero_init;
+   /* Bitfield of ir_variable_mode to zero init */
+   uint32_t zero_init;
    unsigned gl_version;
    gl_shader_stage stage;