Add --canonicalize-ids pass (KhronosGroup#6174)

This is a port of the spirv-remap utility in glslang.

The canonicalize IDs pass is an optimization to improve compression of
SPIR-V binary files via entropy reduction. It transforms SPIR-V to
SPIR-V, remapping IDs. The resulting modules have an increased ID range
(IDs are not as tightly packed around zero), but will compress better
when multiple modules are compressed together, since the compressor's
dictionary can find better cross module commonality. Remapping is
accomplished via canonicalization. Thus, modules can be compressed one
at a time with no loss of quality relative to operating on many modules
at once.

This pass should be run after most optimization passes except for
--strip-debug because this pass will use OpName to canonicalize IDs.
i.e. Run --strip-debug after this pass.

Author: jeremy-lunarg

Android.mk

@@ -169,6 +169,7 @@ SPVTOOLS_OPT_SRC_FILES := \
 		source/opt/redundancy_elimination.cpp \
 		source/opt/register_pressure.cpp \
 		source/opt/relax_float_ops_pass.cpp \
+		source/opt/canonicalize_ids_pass.cpp \
 		source/opt/remove_dontinline_pass.cpp \
 		source/opt/remove_duplicates_pass.cpp \
 		source/opt/remove_unused_interface_variables_pass.cpp \

BUILD.gn

@@ -581,6 +581,8 @@ static_library("spvtools_opt") {
     "source/opt/remove_duplicates_pass.h",
     "source/opt/remove_unused_interface_variables_pass.cpp",
     "source/opt/remove_unused_interface_variables_pass.h",
+    "source/opt/canonicalize_ids_pass.h",
+    "source/opt/canonicalize_ids_pass.cpp",
     "source/opt/replace_desc_array_access_using_var_index.cpp",
     "source/opt/replace_desc_array_access_using_var_index.h",
     "source/opt/replace_invalid_opc.cpp",

include/spirv-tools/optimizer.hpp

@@ -1022,6 +1022,16 @@ Optimizer::PassToken CreateSplitCombinedImageSamplerPass();
 // This pass assumes binding numbers are not applid via decoration groups
 // (OpDecorationGroup).
 Optimizer::PassToken CreateResolveBindingConflictsPass();
+
+// Create a pass to canonicalize IDs to improve compression of SPIR-V binary
+// files. The resulting modules have an increased ID range (IDs are not as
+// tightly packed around zero), but will compress better when multiple modules
+// are compressed together, since the compressor's dictionary can find better
+// cross module commonality. This pass should be run after most optimization
+// passes except for
+// --strip-debug because this pass will use OpName to canonicalize IDs. i.e. Run
+// --strip-debug after this pass.
+Optimizer::PassToken CreateCanonicalizeIdsPass();
 }  // namespace spvtools
 
 #endif  // INCLUDE_SPIRV_TOOLS_OPTIMIZER_HPP_

source/opt/CMakeLists.txt

@@ -104,6 +104,7 @@ set(SPIRV_TOOLS_OPT_SOURCES
   reflect.h
   register_pressure.h
   relax_float_ops_pass.h
+  canonicalize_ids_pass.h
   remove_dontinline_pass.h
   remove_duplicates_pass.h
   remove_unused_interface_variables_pass.h
@@ -222,6 +223,7 @@ set(SPIRV_TOOLS_OPT_SOURCES
   redundancy_elimination.cpp
   register_pressure.cpp
   relax_float_ops_pass.cpp
+  canonicalize_ids_pass.cpp
   remove_dontinline_pass.cpp
   remove_duplicates_pass.cpp
   remove_unused_interface_variables_pass.cpp