Patch modifies existing shader source and replace functionality to work
with environment variables rather than enable dumping on compile time.
Also instead of _mesa_str_checksum, _mesa_sha1_compute is used to avoid
collisions.
Functionality is controlled via 2 environment variables:
MESA_SHADER_DUMP_PATH - path where shader sources are dumped
MESA_SHADER_READ_PATH - path where replacement shaders are read
Signed-off-by: Tapani Pälli <tapani.pa...@intel.com>
Suggested-by: Eero Tamminen <eero.t.tammi...@intel.com>
---
docs/shading.html | 9 +++
src/mesa/main/shaderapi.c | 136 ++++++++++++++++++++++++++++++++--------------
2 files changed, 105 insertions(+), 40 deletions(-)
diff --git a/docs/shading.html b/docs/shading.html
index 77a0ee4..784329e 100644
--- a/docs/shading.html
+++ b/docs/shading.html
@@ -63,6 +63,15 @@ execution. These are generally used for debugging.
Example: export MESA_GLSL=dump,nopt
</p>
+<p>
+Shaders can be dumped and replaced on runtime for debugging purposes.
+This is controlled via following environment variables:
+<ul>
+<li><b>MESA_SHADER_DUMP_PATH</b> - path where shader sources are dumped
+<li><b>MESA_SHADER_READ_PATH</b> - path where replacement shaders are read
+</ul>
+Note, path set must exist before running for dumping or replacing to work.
+</p>
<h2 id="support">GLSL Version</h2>
diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
index 0e0e0d6..d3abfc9 100644
--- a/src/mesa/main/shaderapi.c
+++ b/src/mesa/main/shaderapi.c
@@ -53,15 +53,13 @@
#include "program/prog_parameter.h"
#include "util/ralloc.h"
#include "util/hash_table.h"
+#include "util/mesa-sha1.h"
#include <stdbool.h>
#include "../glsl/glsl_parser_extras.h"
#include "../glsl/ir.h"
#include "../glsl/ir_uniform.h"
#include "../glsl/program.h"
-/** Define this to enable shader substitution (see below) */
-#define SHADER_SUBST 0
-
/**
* Return mask of GLSL_x flags by examining the MESA_GLSL env var.
@@ -1512,24 +1510,101 @@ _mesa_LinkProgram(GLhandleARB programObj)
link_program(ctx, programObj);
}
+/**
+ * Generate a SHA-1 hash value string for given source string.
+ */
+static void
+generate_sha1(const char *source, char sha_str[64])
+{
+ unsigned char sha[20];
+ _mesa_sha1_compute(source, strlen(source), sha);
+ _mesa_sha1_format(sha_str, sha);
+}
+
+/**
+ * Construct a full path for shader replacement functionality using
+ * following format:
+ *
+ * <path>/<stage prefix>_<CHECKSUM>.glsl
+ */
+static void
+construct_name(const gl_shader_stage stage, const char *source,
+ const char *path, char *name, unsigned length)
+{
+ char sha[64];
+ static const char *types[] = {
+ "VS", "TC", "TE", "GS", "FS", "CS",
+ };
+ generate_sha1(source, sha);
+ _mesa_snprintf(name, length, "%s/%s_%s.glsl", path, types[stage],
+ sha);
+}
+
+/**
+ * Write given shader source to a file in MESA_SHADER_DUMP_PATH.
+ */
+static void
+dump_shader(const gl_shader_stage stage, const char *source)
+{
+ char name[PATH_MAX];
+ static bool path_exists = true;
+ char *dump_path;
+ FILE *f;
+
+ if (!path_exists)
+ return NULL;
+
+ dump_path = getenv("MESA_SHADER_DUMP_PATH");
+
+ if (!dump_path) {
+ path_exists = false;
+ return NULL;
+ }
+
+ construct_name(stage, source, dump_path, name, PATH_MAX);
+
+ f = fopen(name, "w");
+ if (f) {
+ fputs(source, f);
+ fclose(f);
+ } else {
+ GET_CURRENT_CONTEXT(ctx);
+ _mesa_warning(ctx, "could not open %s for dumping shader", name);
+ }
+}
/**
* Read shader source code from a file.
* Useful for debugging to override an app's shader.
*/
static GLcharARB *
-read_shader(const char *fname)
+read_shader(const gl_shader_stage stage, const char *source)
{
- int shader_size = 0;
- FILE *f = fopen(fname, "r");
- GLcharARB *buffer, *shader;
- int len;
+ char name[PATH_MAX];
+ char *read_path;
+ static bool path_exists = true;
+ int len, shader_size = 0;
+ GLcharARB *buffer;
+ FILE *f;
- if (!f) {
+ if (!path_exists)
+ return NULL;
+
+ read_path = getenv("MESA_SHADER_READ_PATH");
+
+ if (!read_path) {
+ path_exists = false;
return NULL;
}
+ construct_name(stage, source, read_path, name, PATH_MAX);
+
+ f = fopen(name, "r");
+
+ if (!f)
+ return NULL;
+
/* allocate enough room for the entire shader */
fseek(f, 0, SEEK_END);
shader_size = ftell(f);
@@ -1547,13 +1622,9 @@ read_shader(const char *fname)
fclose(f);
- shader = strdup(buffer);
- free(buffer);
-
- return shader;
+ return buffer;
}
-
/**
* Called via glShaderSource() and glShaderSourceARB() API functions.
* Basically, concatenate the source code strings into one long string
@@ -1566,14 +1637,15 @@ _mesa_ShaderSource(GLhandleARB shaderObj, GLsizei count,
GET_CURRENT_CONTEXT(ctx);
GLint *offsets;
GLsizei i, totalLength;
- GLcharARB *source;
- GLuint checksum;
+ GLcharARB *source, *replacement;
if (!shaderObj || string == NULL) {
_mesa_error(ctx, GL_INVALID_VALUE, "glShaderSourceARB");
return;
}
+ struct gl_shader *sh = _mesa_lookup_shader(ctx, shaderObj);
+
/*
* This array holds offsets of where the appropriate string ends, thus the
* last element will be set to the total length of the source code.
@@ -1620,35 +1692,19 @@ _mesa_ShaderSource(GLhandleARB shaderObj, GLsizei count,
source[totalLength - 1] = '\0';
source[totalLength - 2] = '\0';
- if (SHADER_SUBST) {
- /* Compute the shader's source code checksum then try to open a file
- * named newshader_<CHECKSUM>. If it exists, use it in place of the
- * original shader source code. For debugging.
- */
- char filename[100];
- GLcharARB *newSource;
-
- checksum = _mesa_str_checksum(source);
-
- _mesa_snprintf(filename, sizeof(filename), "newshader_%d", checksum);
+ /* Dump original shader source to MESA_SHADER_DUMP_PATH and replace
+ * if corresponding entry found from MESA_SHADER_READ_PATH.
+ */
+ dump_shader(sh->Stage, source);
- newSource = read_shader(filename);
- if (newSource) {
- fprintf(stderr, "Mesa: Replacing shader %u chksum=%d with %s\n",
- shaderObj, checksum, filename);
- free(source);
- source = newSource;
- }
+ replacement = read_shader(sh->Stage, source);
+ if (replacement) {
+ free(source);
+ source = replacement;
}
shader_source(ctx, shaderObj, source);
- if (SHADER_SUBST) {
- struct gl_shader *sh = _mesa_lookup_shader(ctx, shaderObj);
- if (sh)
- sh->SourceChecksum = checksum; /* save original checksum */
- }
-
free(offsets);
}
--
2.4.3
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