On Friday, May 20, 2016 4:53:24 PM PDT Jason Ekstrand wrote: > This prevents array overflow when the block is actually an array of UBOs or > SSBOs. On some hardware such as i965, such overflows can cause GPU hangs. > > Reviewed-by: Ian Romanick <ian.d.roman...@intel.com> > --- > src/compiler/glsl/ir_optimization.h | 2 +- > src/compiler/glsl/linker.cpp | 3 ++- > src/compiler/glsl/lower_ubo_reference.cpp | 36 ++++++++++++++++++++++++++ +---- > src/mesa/drivers/dri/i965/brw_compiler.c | 1 + > src/mesa/main/mtypes.h | 3 +++ > 5 files changed, 39 insertions(+), 6 deletions(-) > > diff --git a/src/compiler/glsl/ir_optimization.h b/src/compiler/glsl/ ir_optimization.h > index 5fc2740..4afa37e 100644 > --- a/src/compiler/glsl/ir_optimization.h > +++ b/src/compiler/glsl/ir_optimization.h > @@ -123,7 +123,7 @@ bool lower_clip_distance(gl_shader *shader); > void lower_output_reads(unsigned stage, exec_list *instructions); > bool lower_packing_builtins(exec_list *instructions, int op_mask); > void lower_shared_reference(struct gl_shader *shader, unsigned *shared_size); > -void lower_ubo_reference(struct gl_shader *shader); > +void lower_ubo_reference(struct gl_shader *shader, bool clamp_block_indices); > void lower_packed_varyings(void *mem_ctx, > unsigned locations_used, ir_variable_mode mode, > unsigned gs_input_vertices, gl_shader *shader, > diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp > index c7a7c63..446b1fc 100644 > --- a/src/compiler/glsl/linker.cpp > +++ b/src/compiler/glsl/linker.cpp > @@ -4882,7 +4882,8 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) > &ctx->Const.ShaderCompilerOptions[i]; > > if (options->LowerBufferInterfaceBlocks) > - lower_ubo_reference(prog->_LinkedShaders[i]); > + lower_ubo_reference(prog->_LinkedShaders[i], > + options->ClampBlockIndicesToArrayBounds); > > if (options->LowerShaderSharedVariables) > lower_shared_reference(prog->_LinkedShaders[i], > diff --git a/src/compiler/glsl/lower_ubo_reference.cpp b/src/compiler/glsl/ lower_ubo_reference.cpp > index 1a0140f..749deed 100644 > --- a/src/compiler/glsl/lower_ubo_reference.cpp > +++ b/src/compiler/glsl/lower_ubo_reference.cpp > @@ -44,8 +44,10 @@ namespace { > class lower_ubo_reference_visitor : > public lower_buffer_access::lower_buffer_access { > public: > - lower_ubo_reference_visitor(struct gl_shader *shader) > - : shader(shader), struct_field(NULL), variable(NULL) > + lower_ubo_reference_visitor(struct gl_shader *shader, > + bool clamp_block_indices) > + : shader(shader), clamp_block_indices(clamp_block_indices), > + struct_field(NULL), variable(NULL) > { > } > > @@ -104,6 +106,7 @@ public: > ir_visitor_status visit_enter(ir_call *ir); > > struct gl_shader *shader; > + bool clamp_block_indices; > struct gl_uniform_buffer_variable *ubo_var; > const struct glsl_struct_field *struct_field; > ir_variable *variable; > @@ -242,6 +245,26 @@ interface_field_name(void *mem_ctx, char *base_name, ir_rvalue *d, > return NULL; > } > > +static ir_rvalue * > +clamp_to_array_bounds(void *mem_ctx, ir_rvalue *index, const glsl_type *type) > +{ > + assert(type->is_array()); > + > + const unsigned array_size = type->arrays_of_arrays_size();
Can you actually have arrays of arrays of UBOs/SSBOs? Even still, isn't this an index into the outermost array? So don't we want to simply clamp it to type->length, rather than the flattened multi-dimensional size? With that fixed or refuted, the series is: Reviewed-by: Kenneth Graunke <kenn...@whitecape.org> > + > + ir_constant *max_index = new(mem_ctx) ir_constant(array_size - 1); > + max_index->type = index->type; > + > + ir_constant *zero = new(mem_ctx) ir_constant(0); > + zero->type = index->type; > + > + if (index->type->base_type == GLSL_TYPE_INT) > + index = max2(index, zero); > + index = min2(index, max_index); > + > + return index; > +} > + > void > lower_ubo_reference_visitor::setup_for_load_or_store(void *mem_ctx, > ir_variable *var, > @@ -258,6 +281,11 @@ lower_ubo_reference_visitor::setup_for_load_or_store(void *mem_ctx, > interface_field_name(mem_ctx, (char *) var->get_interface_type()- >name, > deref, &nonconst_block_index); > > + if (nonconst_block_index && clamp_block_indices) { > + nonconst_block_index = > + clamp_to_array_bounds(mem_ctx, nonconst_block_index, var->type); > + } > + > /* Locate the block by interface name */ > unsigned num_blocks; > struct gl_uniform_block **blocks; > @@ -1062,9 +1090,9 @@ lower_ubo_reference_visitor::visit_enter(ir_call *ir) > } /* unnamed namespace */ > > void > -lower_ubo_reference(struct gl_shader *shader) > +lower_ubo_reference(struct gl_shader *shader, bool clamp_block_indices) > { > - lower_ubo_reference_visitor v(shader); > + lower_ubo_reference_visitor v(shader, clamp_block_indices); > > /* Loop over the instructions lowering references, because we take > * a deref of a UBO array using a UBO dereference as the index will > diff --git a/src/mesa/drivers/dri/i965/brw_compiler.c b/src/mesa/drivers/ dri/i965/brw_compiler.c > index 82131db..3f17589 100644 > --- a/src/mesa/drivers/dri/i965/brw_compiler.c > +++ b/src/mesa/drivers/dri/i965/brw_compiler.c > @@ -188,6 +188,7 @@ brw_compiler_create(void *mem_ctx, const struct brw_device_info *devinfo) > } > > compiler->glsl_compiler_options[i].LowerBufferInterfaceBlocks = true; > + compiler->glsl_compiler_options[i].ClampBlockIndicesToArrayBounds = true; > } > > compiler- >glsl_compiler_options[MESA_SHADER_TESS_CTRL].EmitNoIndirectInput = false; > diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h > index 569e0ac..24f442f 100644 > --- a/src/mesa/main/mtypes.h > +++ b/src/mesa/main/mtypes.h > @@ -2949,6 +2949,9 @@ struct gl_shader_compiler_options > > GLboolean LowerBufferInterfaceBlocks; /**< Lower UBO and SSBO access to intrinsics. */ > > + /** Clamp UBO and SSBO block indices so they don't go out-of-bounds. */ > + GLboolean ClampBlockIndicesToArrayBounds; > + > GLboolean LowerShaderSharedVariables; /**< Lower compute shader shared > * variable access to intrinsics. */ > >
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