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authorAndrey Tuganov <andreyt@google.com>2017-10-27 11:31:39 -0400
committerDavid Neto <dneto@google.com>2017-10-28 18:38:13 -0400
commit6724c272515686398105813de0801407566ae914 (patch)
tree445ae4c4a0a6df9ca002f90eb72d38202df34a2c /source/comp
parentf063f91d24f83790ba5c3fccd127624260c472f0 (diff)
Compression: removed 'presumed index' feature
The feature used to improve compression of const integers which were presumed to be indices. Now obsolete as descriptor-based compression does this in a more generalized way.
Diffstat (limited to 'source/comp')
-rw-r--r--source/comp/markv_codec.cpp67
1 files changed, 1 insertions, 66 deletions
diff --git a/source/comp/markv_codec.cpp b/source/comp/markv_codec.cpp
index 46fb09b5..b5df2b06 100644
--- a/source/comp/markv_codec.cpp
+++ b/source/comp/markv_codec.cpp
@@ -103,8 +103,6 @@ enum : uint64_t {
kMtfTypeIntScalarOrVector,
// All types declared as return types in OpTypeFunction.
kMtfTypeReturnedByFunction,
- // All object ids which are integer constants.
- kMtfConstInteger,
// All composite objects.
kMtfComposite,
// All bool objects or vectors of bools.
@@ -139,10 +137,6 @@ enum : uint64_t {
kMtfIdDescriptorSpaceBegin = 0x100000000,
};
-// Used by "presumed index" technique which does special treatment of integer
-// constants no greater than this value.
-const uint32_t kMarkvMaxPresumedAccessIndex = 31;
-
// Signals that the value is not in the coding scheme and a fallback method
// needs to be used.
const uint64_t kMarkvNoneOfTheAbove = MarkvModel::GetMarkvNoneOfTheAbove();
@@ -271,7 +265,7 @@ size_t GetNumBitsToNextByte(size_t bit_pos) {
// Defines and returns current MARK-V version.
uint32_t GetMarkvVersion() {
const uint32_t kVersionMajor = 1;
- const uint32_t kVersionMinor = 2;
+ const uint32_t kVersionMinor = 3;
return kVersionMinor | (kVersionMajor << 16);
}
@@ -556,11 +550,6 @@ class MarkvCodecBase {
// List of instructions in the order they are given in the module.
std::vector<std::unique_ptr<const Instruction>> instructions_;
- // Maps used for the 'presumed id' techniques. Maps small constant integer
- // value to its id and back.
- std::map<uint32_t, uint32_t> presumed_index_to_id_;
- std::map<uint32_t, uint32_t> id_to_presumed_index_;
-
// Container/computer for id descriptors.
IdDescriptorCollection id_descriptors_;
@@ -1010,21 +999,6 @@ void MarkvCodecBase::ProcessCurInstruction() {
if (multi_mtf_.HasValue(kMtfTypeComposite, inst_.type_id))
multi_mtf_.Insert(kMtfComposite, inst_.result_id);
- if (inst_.opcode == SpvOpConstant) {
- if (multi_mtf_.HasValue(
- GetMtfIdGeneratedByOpcode(SpvOpTypeInt), inst_.type_id)) {
- multi_mtf_.Insert(kMtfConstInteger, inst_.result_id);
- const uint32_t presumed_index = inst_.words[3];
- if (presumed_index <= kMarkvMaxPresumedAccessIndex) {
- const auto result =
- presumed_index_to_id_.emplace(presumed_index, inst_.result_id);
- if (result.second) {
- id_to_presumed_index_.emplace(inst_.result_id, presumed_index);
- }
- }
- }
- }
-
switch (type_inst->opcode()) {
case SpvOpTypeInt:
case SpvOpTypeBool:
@@ -1799,19 +1773,6 @@ spv_result_t MarkvDecoder::DecodeExistingId(uint64_t mtf, uint32_t* id) {
}
spv_result_t MarkvEncoder::EncodeRefId(uint32_t id) {
- // TODO(atgoo@github.com) This might not be needed as EncodeIdWithDescriptor
- // can handle SpvOpAccessChain indices if enough statistics is collected.
- if (inst_.opcode == SpvOpAccessChain && operand_index_ >= 3) {
- const auto it = id_to_presumed_index_.find(id);
- if (it != id_to_presumed_index_.end()) {
- writer_.WriteBits(1, 1);
- writer_.WriteFixedWidth(it->second, kMarkvMaxPresumedAccessIndex);
- return SPV_SUCCESS;
- }
-
- writer_.WriteBits(0, 1);
- }
-
{
// Try to encode using id descriptor mtfs.
const spv_result_t result = EncodeIdWithDescriptor(id);
@@ -1849,32 +1810,6 @@ spv_result_t MarkvEncoder::EncodeRefId(uint32_t id) {
}
spv_result_t MarkvDecoder::DecodeRefId(uint32_t* id) {
- if (inst_.opcode == SpvOpAccessChain && operand_index_ >= 3) {
- uint64_t use_presumed_index_technique = 0;
- if (!reader_.ReadBits(&use_presumed_index_technique, 1))
- return Diag(SPV_ERROR_INVALID_BINARY)
- << "Failed to read use_presumed_index_technique flag";
-
- if (use_presumed_index_technique) {
- uint64_t value = 0;
- if (!reader_.ReadFixedWidth(&value, kMarkvMaxPresumedAccessIndex))
- return Diag(SPV_ERROR_INVALID_BINARY)
- << "Failed to read presumed_index";
-
- const uint32_t presumed_index = static_cast<uint32_t>(value);
-
- const auto it = presumed_index_to_id_.find(presumed_index);
- if (it == presumed_index_to_id_.end()) {
- assert(0);
- return Diag(SPV_ERROR_INTERNAL)
- << "Presumed index id not found";
- }
-
- *id = it->second;
- return SPV_SUCCESS;
- }
- }
-
{
const spv_result_t result = DecodeIdWithDescriptor(id);
if (result != SPV_UNSUPPORTED)