svga: move temp register index assertions

The assertion recently added in dst_register() was invalid because that
function is also (suprisingly) used to declare constant registers.

Move the assertion to the callers where we're really creating temp
registers and add some code to prevent emitting invalid temp register
indexes for release builds.

Also, update the comment for get_temp().  It didn't return -1 if it
ran out of registers and none of the callers checked for that.

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>

diff --git a/src/gallium/drivers/svga/svga_tgsi_emit.h b/src/gallium/drivers/svga/svga_tgsi_emit.h
index 1769d62570d948d88d9a525cb66f2cf92736eb92..73c4cdabefcdde613b0e213d824cd5a1479e31ce 100644 (file)
--- a/src/gallium/drivers/svga/svga_tgsi_emit.h
+++ b/src/gallium/drivers/svga/svga_tgsi_emit.h
@@ -256,6 +256,12 @@ inst_token( unsigned opcode )
    return inst;
 }
 
+
+/**
+ * Create an instance of a SVGA3dShaderDestToken.
+ * Note that this function is used to create tokens for output registers,
+ * temp registers AND constants (see emit_def_const()).
+ */
 static INLINE SVGA3dShaderDestToken 
 dst_register( unsigned file,
               int number )
@@ -266,8 +272,6 @@ dst_register( unsigned file,
    assert(number < (1 << 11));
    assert(file <= SVGA3DREG_PREDICATE);
 
-   assert(number < SVGA3D_TEMPREG_MAX);
-
    dest.value = 0;
    dest.num = number;
    dest.type_upper = file >> 3;

diff --git a/src/gallium/drivers/svga/svga_tgsi_insn.c b/src/gallium/drivers/svga/svga_tgsi_insn.c
index 5a9af89bf037a9423d47863c1c0045ad1cca5aef..5e6d1fbc9048b22ec1b0f4c94a711d02691b30d5 100644 (file)
--- a/src/gallium/drivers/svga/svga_tgsi_insn.c
+++ b/src/gallium/drivers/svga/svga_tgsi_insn.c
@@ -105,8 +105,12 @@ translate_dst_register( struct svga_shader_emitter *emit,
       break;
 
    default:
-      dest = dst_register( translate_file( reg->Register.File ),
-                           reg->Register.Index );
+      {
+         unsigned index = reg->Register.Index;
+         assert(index < SVGA3D_TEMPREG_MAX);
+         index = MIN2(index, SVGA3D_TEMPREG_MAX - 1);
+         dest = dst_register(translate_file(reg->Register.File), index);
+      }                 
       break;
    }
 
@@ -258,13 +262,16 @@ translate_src_register( const struct svga_shader_emitter *emit,
 
 
 /*
- * Get a temporary register, return -1 if none available
+ * Get a temporary register.
+ * Note: if we exceed the temporary register limit we just use
+ * register SVGA3D_TEMPREG_MAX - 1.
  */
 static INLINE SVGA3dShaderDestToken 
 get_temp( struct svga_shader_emitter *emit )
 {
    int i = emit->nr_hw_temp + emit->internal_temp_count++;
-
+   assert(i < SVGA3D_TEMPREG_MAX);
+   i = MIN2(i, SVGA3D_TEMPREG_MAX - 1);
    return dst_register( SVGA3DREG_TEMP, i );
 }