mesa/glsl: delete previously linked shaders earlier when linking

This moves the delete linked shaders call to
_mesa_clear_shader_program_data() which makes sure we delete them
before returning due to any validation problems.

It also reduces some code duplication.

From the OpenGL 4.5 Core spec:

   "If LinkProgram failed, any information about a previous link of
   that program object is lost. Thus, a failed link does not restore
   the old state of program.

   ...

   If one of these commands is called with a program for which
   LinkProgram failed, no error is generated unless otherwise noted.
   Implementations may return information on variables and interface
   blocks that would have been active had the program been linked
   successfully. In cases where the link failed because the program
   required too many resources, these commands may help applications
   determine why limits were exceeded."

Therefore it's expected that we shouldn't be able to query the
program that failed to link and retrieve information about a
previously successful link.

Before this change the linker was doing validation before freeing
the previously linked shaders and therefore could exit on failure
before they were freed.

This change also fixes an issue in compat profile where a program
with no shaders attached is expect to fall back to fixed function
but was instead trying to relink IR from a previous link.

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97715
Cc: "13.0" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit d2861d682a235993844989f7742c9539c3e10245)

4 files changed, 12 insertions, 11 deletions

diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
index f5c177e..5220488 100644
--- a/src/compiler/glsl/linker.cpp
+++ b/src/compiler/glsl/linker.cpp
@@ -4785,14 +4785,6 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
                    "type of shader\n");
    }
 
-   for (unsigned int i = 0; i < MESA_SHADER_STAGES; i++) {
-      if (prog->_LinkedShaders[i] != NULL) {
-         _mesa_delete_linked_shader(ctx, prog->_LinkedShaders[i]);
-      }
-
-      prog->_LinkedShaders[i] = NULL;
-   }
-
    /* Link all shaders for a particular stage and validate the result.
     */
    for (int stage = 0; stage < MESA_SHADER_STAGES; stage++) {
diff --git a/src/compiler/glsl/standalone.cpp b/src/compiler/glsl/standalone.cpp
index 055c433..f096490 100644
--- a/src/compiler/glsl/standalone.cpp
+++ b/src/compiler/glsl/standalone.cpp
@@ -421,7 +421,7 @@ standalone_compile_shader(const struct standalone_options *_options,
    }
 
    if ((status == EXIT_SUCCESS) && options->do_link)  {
-      _mesa_clear_shader_program_data(whole_program);
+      _mesa_clear_shader_program_data(ctx, whole_program);
 
       link_shaders(ctx, whole_program);
       status = (whole_program->LinkStatus) ? EXIT_SUCCESS : EXIT_FAILURE;
diff --git a/src/compiler/glsl/standalone_scaffolding.cpp b/src/compiler/glsl/standalone_scaffolding.cpp
index 35e40d6..d229368 100644
--- a/src/compiler/glsl/standalone_scaffolding.cpp
+++ b/src/compiler/glsl/standalone_scaffolding.cpp
@@ -123,8 +123,16 @@ _mesa_delete_linked_shader(struct gl_context *ctx,
 }
 
 void
-_mesa_clear_shader_program_data(struct gl_shader_program *shProg)
+_mesa_clear_shader_program_data(struct gl_context *ctx,
+                                struct gl_shader_program *shProg)
 {
+   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
+      if (shProg->_LinkedShaders[i] != NULL) {
+         _mesa_delete_linked_shader(ctx, shProg->_LinkedShaders[i]);
+         shProg->_LinkedShaders[i] = NULL;
+      }
+   }
+
    shProg->NumUniformStorage = 0;
    shProg->UniformStorage = NULL;
    shProg->NumUniformRemapTable = 0;
diff --git a/src/compiler/glsl/standalone_scaffolding.h b/src/compiler/glsl/standalone_scaffolding.h
index b56dd3e..2c04548 100644
--- a/src/compiler/glsl/standalone_scaffolding.h
+++ b/src/compiler/glsl/standalone_scaffolding.h
@@ -56,7 +56,8 @@ _mesa_delete_linked_shader(struct gl_context *ctx,
                            struct gl_linked_shader *sh);
 
 extern "C" void
-_mesa_clear_shader_program_data(struct gl_shader_program *);
+_mesa_clear_shader_program_data(struct gl_context *ctx,
+                                struct gl_shader_program *);
 
 extern "C" void
 _mesa_shader_debug(struct gl_context *ctx, GLenum type, GLuint *id,