gallivm: Compile flag to debug TGSI execution through printfs.

It is similar to tgsi_exec.c's DEBUG_EXECUTION compile flag.

I had prototyped this for a while while debugging an issue, but finally
cleaned this up and added a few more bells and whistles.

v2: Use '$' as marker; better output. Thanks to Brian, Zack and Roland
reviews.

Here is a sample output.

    CONST[0].x =  0.00625000009 0.00625000009 0.00625000009 0.00625000009
    CONST[0].y =  -0.00714285718 -0.00714285718 -0.00714285718 -0.00714285718
    CONST[0].z =  -1 -1 -1 -1
    CONST[0].w =  1 1 1 1
    IN[0].x =  143.5 175.5 175.5 143.5
    IN[0].y =  123.5 123.5 155.5 155.5
    IN[0].z =  0 0 0 0
    IN[0].w =  1 1 1 1
$   1: RCP TEMP[0].w, IN[0].wwww
    TEMP[0].w =  1 1 1 1
$   2: MAD TEMP[0].xy, IN[0], CONST[0], CONST[0].zwzw
    TEMP[0].x =  -0.103124976 0.0968750715 0.0968750715 -0.103124976
    TEMP[0].y =  0.117857158 0.117857158 -0.110714316 -0.110714316
$   3: MUL OUT[0].xy, TEMP[0], TEMP[0].wwww
    OUT[0].x =  -0.103124976 0.0968750715 0.0968750715 -0.103124976
    OUT[0].y =  0.117857158 0.117857158 -0.110714316 -0.110714316
$   4: MUL OUT[0].z, IN[0].zzzz, TEMP[0].wwww
    OUT[0].z =  0 0 0 0
$   5: MOV OUT[0].w, TEMP[0]
    OUT[0].w =  1 1 1 1
$   6: END
    OUT[0].x =  -0.103124976 0.0968750715 0.0968750715 -0.103124976
    OUT[0].y =  0.117857158 0.117857158 -0.110714316 -0.110714316
    OUT[0].z =  0 0 0 0
    OUT[0].w =  1 1 1 1

1 files changed, 23 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/tgsi/tgsi_dump.c b/src/gallium/auxiliary/tgsi/tgsi_dump.c
index 7f6a3d8ad8f..77bca623082 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_dump.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_dump.c
@@ -721,3 +721,26 @@ tgsi_dump_str(
 
    tgsi_iterate_shader( tokens, &ctx.base.iter );
 }
+
+void
+tgsi_dump_instruction_str(
+   const struct tgsi_full_instruction *inst,
+   uint instno,
+   char *str,
+   size_t size)
+{
+   struct str_dump_ctx ctx;
+
+   ctx.base.instno = instno;
+   ctx.base.immno = instno;
+   ctx.base.indent = 0;
+   ctx.base.dump_printf = &str_dump_ctx_printf;
+   ctx.base.indentation = 0;
+
+   ctx.str = str;
+   ctx.str[0] = 0;
+   ctx.ptr = str;
+   ctx.left = (int)size;
+
+   iter_instruction( &ctx.base.iter, (struct tgsi_full_instruction *)inst );
+}