[Mesa-dev] [PATCH] tgsi/gs: bound max output vertices in shader

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This limits the number of emitted vertices to the shaders max output
vertices, and avoids us writing things into memory that isn't big
enough for it.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/gallium/auxiliary/tgsi/tgsi_exec.c | 8 ++++++++
 src/gallium/auxiliary/tgsi/tgsi_exec.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.c b/src/gallium/auxiliary/tgsi/tgsi_exec.c
index 69d98fd..d848348 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.c
@@ -789,6 +789,11 @@ tgsi_exec_machine_bind_shader(
          break;
 
       case TGSI_TOKEN_TYPE_PROPERTY:
+         if (mach->Processor == TGSI_PROCESSOR_GEOMETRY) {
+            if (parse.FullToken.FullProperty.Property.PropertyName == TGSI_PROPERTY_GS_MAX_OUTPUT_VERTICES) {
+               mach->MaxOutputVertices = parse.FullToken.FullProperty.u[0].Data;
+            }
+         }
          break;
 
       default:
@@ -1621,6 +1626,9 @@ emit_vertex(struct tgsi_exec_machine *mach)
          if ((mach->ExecMask & (1 << i)))
    */
    if (mach->ExecMask) {
+      if (mach->Primitives[mach->Temps[TEMP_PRIMITIVE_I].xyzw[TEMP_PRIMITIVE_C].u[0]] >= mach->MaxOutputVertices)
+         return;
+
       mach->Temps[TEMP_OUTPUT_I].xyzw[TEMP_OUTPUT_C].u[0] += mach->NumOutputs;
       mach->Primitives[mach->Temps[TEMP_PRIMITIVE_I].xyzw[TEMP_PRIMITIVE_C].u[0]]++;
    }
diff --git a/src/gallium/auxiliary/tgsi/tgsi_exec.h b/src/gallium/auxiliary/tgsi/tgsi_exec.h
index 7a82f69..d53c4ba 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_exec.h
+++ b/src/gallium/auxiliary/tgsi/tgsi_exec.h
@@ -297,6 +297,7 @@ struct tgsi_exec_machine
    unsigned                      *Primitives;
    unsigned                       NumOutputs;
    unsigned                       MaxGeometryShaderOutputs;
+   unsigned                       MaxOutputVertices;
 
    /* FRAGMENT processor only. */
    const struct tgsi_interp_coef *InterpCoefs;
-- 
1.9.3