SPIRV-Tools/source/opt/set_spec_constant_default_value_pass.cpp
Nathan Gauër 1a7f71afb4
clean: constexpr-ify and unify anon namespace use (#4991)
Constexpr guaranteed no runtime init in addition to const semantics.
Moving all opt/ to constexpr.
Moving all compile-unit statics to anonymous namespaces to uniformize
the method used (anonymous namespace vs static has the same behavior
here AFAIK).

Signed-off-by: Nathan Gauër <brioche@google.com>
2022-11-17 19:02:50 +01:00

393 lines
15 KiB
C++

// Copyright (c) 2016 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/opt/set_spec_constant_default_value_pass.h"
#include <algorithm>
#include <cctype>
#include <cstring>
#include <tuple>
#include <vector>
#include "source/opt/def_use_manager.h"
#include "source/opt/ir_context.h"
#include "source/opt/type_manager.h"
#include "source/opt/types.h"
#include "source/util/make_unique.h"
#include "source/util/parse_number.h"
#include "spirv-tools/libspirv.h"
namespace spvtools {
namespace opt {
namespace {
using utils::EncodeNumberStatus;
using utils::NumberType;
using utils::ParseAndEncodeNumber;
using utils::ParseNumber;
// Given a numeric value in a null-terminated c string and the expected type of
// the value, parses the string and encodes it in a vector of words. If the
// value is a scalar integer or floating point value, encodes the value in
// SPIR-V encoding format. If the value is 'false' or 'true', returns a vector
// with single word with value 0 or 1 respectively. Returns the vector
// containing the encoded value on success. Otherwise returns an empty vector.
std::vector<uint32_t> ParseDefaultValueStr(const char* text,
const analysis::Type* type) {
std::vector<uint32_t> result;
if (!strcmp(text, "true") && type->AsBool()) {
result.push_back(1u);
} else if (!strcmp(text, "false") && type->AsBool()) {
result.push_back(0u);
} else {
NumberType number_type = {32, SPV_NUMBER_UNSIGNED_INT};
if (const auto* IT = type->AsInteger()) {
number_type.bitwidth = IT->width();
number_type.kind =
IT->IsSigned() ? SPV_NUMBER_SIGNED_INT : SPV_NUMBER_UNSIGNED_INT;
} else if (const auto* FT = type->AsFloat()) {
number_type.bitwidth = FT->width();
number_type.kind = SPV_NUMBER_FLOATING;
} else {
// Does not handle types other then boolean, integer or float. Returns
// empty vector.
result.clear();
return result;
}
EncodeNumberStatus rc = ParseAndEncodeNumber(
text, number_type, [&result](uint32_t word) { result.push_back(word); },
nullptr);
// Clear the result vector on failure.
if (rc != EncodeNumberStatus::kSuccess) {
result.clear();
}
}
return result;
}
// Given a bit pattern and a type, checks if the bit pattern is compatible
// with the type. If so, returns the bit pattern, otherwise returns an empty
// bit pattern. If the given bit pattern is empty, returns an empty bit
// pattern. If the given type represents a SPIR-V Boolean type, the bit pattern
// to be returned is determined with the following standard:
// If any words in the input bit pattern are non zero, returns a bit pattern
// with 0x1, which represents a 'true'.
// If all words in the bit pattern are zero, returns a bit pattern with 0x0,
// which represents a 'false'.
// For integer and floating point types narrower than 32 bits, the upper bits
// in the input bit pattern are ignored. Instead the upper bits are set
// according to SPIR-V literal requirements: sign extend a signed integer, and
// otherwise set the upper bits to zero.
std::vector<uint32_t> ParseDefaultValueBitPattern(
const std::vector<uint32_t>& input_bit_pattern,
const analysis::Type* type) {
std::vector<uint32_t> result;
if (type->AsBool()) {
if (std::any_of(input_bit_pattern.begin(), input_bit_pattern.end(),
[](uint32_t i) { return i != 0; })) {
result.push_back(1u);
} else {
result.push_back(0u);
}
return result;
} else if (const auto* IT = type->AsInteger()) {
const auto width = IT->width();
assert(width > 0);
const auto adjusted_width = std::max(32u, width);
if (adjusted_width == input_bit_pattern.size() * sizeof(uint32_t) * 8) {
result = std::vector<uint32_t>(input_bit_pattern);
if (width < 32) {
const uint32_t high_active_bit = (1u << width) >> 1;
if (IT->IsSigned() && (high_active_bit & result[0])) {
// Sign extend. This overwrites the sign bit again, but that's ok.
result[0] = result[0] | ~(high_active_bit - 1);
} else {
// Upper bits must be zero.
result[0] = result[0] & ((1u << width) - 1);
}
}
return result;
}
} else if (const auto* FT = type->AsFloat()) {
const auto width = FT->width();
const auto adjusted_width = std::max(32u, width);
if (adjusted_width == input_bit_pattern.size() * sizeof(uint32_t) * 8) {
result = std::vector<uint32_t>(input_bit_pattern);
if (width < 32) {
// Upper bits must be zero.
result[0] = result[0] & ((1u << width) - 1);
}
return result;
}
}
result.clear();
return result;
}
// Returns true if the given instruction's result id could have a SpecId
// decoration.
bool CanHaveSpecIdDecoration(const Instruction& inst) {
switch (inst.opcode()) {
case spv::Op::OpSpecConstant:
case spv::Op::OpSpecConstantFalse:
case spv::Op::OpSpecConstantTrue:
return true;
default:
return false;
}
}
// Given a decoration group defining instruction that is decorated with SpecId
// decoration, finds the spec constant defining instruction which is the real
// target of the SpecId decoration. Returns the spec constant defining
// instruction if such an instruction is found, otherwise returns a nullptr.
Instruction* GetSpecIdTargetFromDecorationGroup(
const Instruction& decoration_group_defining_inst,
analysis::DefUseManager* def_use_mgr) {
// Find the OpGroupDecorate instruction which consumes the given decoration
// group. Note that the given decoration group has SpecId decoration, which
// is unique for different spec constants. So the decoration group cannot be
// consumed by different OpGroupDecorate instructions. Therefore we only need
// the first OpGroupDecoration instruction that uses the given decoration
// group.
Instruction* group_decorate_inst = nullptr;
if (def_use_mgr->WhileEachUser(&decoration_group_defining_inst,
[&group_decorate_inst](Instruction* user) {
if (user->opcode() ==
spv::Op::OpGroupDecorate) {
group_decorate_inst = user;
return false;
}
return true;
}))
return nullptr;
// Scan through the target ids of the OpGroupDecorate instruction. There
// should be only one spec constant target consumes the SpecId decoration.
// If multiple target ids are presented in the OpGroupDecorate instruction,
// they must be the same one that defined by an eligible spec constant
// instruction. If the OpGroupDecorate instruction has different target ids
// or a target id is not defined by an eligible spec cosntant instruction,
// returns a nullptr.
Instruction* target_inst = nullptr;
for (uint32_t i = 1; i < group_decorate_inst->NumInOperands(); i++) {
// All the operands of a OpGroupDecorate instruction should be of type
// SPV_OPERAND_TYPE_ID.
uint32_t candidate_id = group_decorate_inst->GetSingleWordInOperand(i);
Instruction* candidate_inst = def_use_mgr->GetDef(candidate_id);
if (!candidate_inst) {
continue;
}
if (!target_inst) {
// If the spec constant target has not been found yet, check if the
// candidate instruction is the target.
if (CanHaveSpecIdDecoration(*candidate_inst)) {
target_inst = candidate_inst;
} else {
// Spec id decoration should not be applied on other instructions.
// TODO(qining): Emit an error message in the invalid case once the
// error handling is done.
return nullptr;
}
} else {
// If the spec constant target has been found, check if the candidate
// instruction is the same one as the target. The module is invalid if
// the candidate instruction is different with the found target.
// TODO(qining): Emit an error messaage in the invalid case once the
// error handling is done.
if (candidate_inst != target_inst) return nullptr;
}
}
return target_inst;
}
} // namespace
Pass::Status SetSpecConstantDefaultValuePass::Process() {
// The operand index of decoration target in an OpDecorate instruction.
constexpr uint32_t kTargetIdOperandIndex = 0;
// The operand index of the decoration literal in an OpDecorate instruction.
constexpr uint32_t kDecorationOperandIndex = 1;
// The operand index of Spec id literal value in an OpDecorate SpecId
// instruction.
constexpr uint32_t kSpecIdLiteralOperandIndex = 2;
// The number of operands in an OpDecorate SpecId instruction.
constexpr uint32_t kOpDecorateSpecIdNumOperands = 3;
// The in-operand index of the default value in a OpSpecConstant instruction.
constexpr uint32_t kOpSpecConstantLiteralInOperandIndex = 0;
bool modified = false;
// Scan through all the annotation instructions to find 'OpDecorate SpecId'
// instructions. Then extract the decoration target of those instructions.
// The decoration targets should be spec constant defining instructions with
// opcode: OpSpecConstant{|True|False}. The spec id of those spec constants
// will be used to look up their new default values in the mapping from
// spec id to new default value strings. Once a new default value string
// is found for a spec id, the string will be parsed according to the target
// spec constant type. The parsed value will be used to replace the original
// default value of the target spec constant.
for (Instruction& inst : context()->annotations()) {
// Only process 'OpDecorate SpecId' instructions
if (inst.opcode() != spv::Op::OpDecorate) continue;
if (inst.NumOperands() != kOpDecorateSpecIdNumOperands) continue;
if (inst.GetSingleWordInOperand(kDecorationOperandIndex) !=
uint32_t(spv::Decoration::SpecId)) {
continue;
}
// 'inst' is an OpDecorate SpecId instruction.
uint32_t spec_id = inst.GetSingleWordOperand(kSpecIdLiteralOperandIndex);
uint32_t target_id = inst.GetSingleWordOperand(kTargetIdOperandIndex);
// Find the spec constant defining instruction. Note that the
// target_id might be a decoration group id.
Instruction* spec_inst = nullptr;
if (Instruction* target_inst = get_def_use_mgr()->GetDef(target_id)) {
if (target_inst->opcode() == spv::Op::OpDecorationGroup) {
spec_inst =
GetSpecIdTargetFromDecorationGroup(*target_inst, get_def_use_mgr());
} else {
spec_inst = target_inst;
}
} else {
continue;
}
if (!spec_inst) continue;
// Get the default value bit pattern for this spec id.
std::vector<uint32_t> bit_pattern;
if (spec_id_to_value_str_.size() != 0) {
// Search for the new string-form default value for this spec id.
auto iter = spec_id_to_value_str_.find(spec_id);
if (iter == spec_id_to_value_str_.end()) {
continue;
}
// Gets the string of the default value and parses it to bit pattern
// with the type of the spec constant.
const std::string& default_value_str = iter->second;
bit_pattern = ParseDefaultValueStr(
default_value_str.c_str(),
context()->get_type_mgr()->GetType(spec_inst->type_id()));
} else {
// Search for the new bit-pattern-form default value for this spec id.
auto iter = spec_id_to_value_bit_pattern_.find(spec_id);
if (iter == spec_id_to_value_bit_pattern_.end()) {
continue;
}
// Gets the bit-pattern of the default value from the map directly.
bit_pattern = ParseDefaultValueBitPattern(
iter->second,
context()->get_type_mgr()->GetType(spec_inst->type_id()));
}
if (bit_pattern.empty()) continue;
// Update the operand bit patterns of the spec constant defining
// instruction.
switch (spec_inst->opcode()) {
case spv::Op::OpSpecConstant:
// If the new value is the same with the original value, no
// need to do anything. Otherwise update the operand words.
if (spec_inst->GetInOperand(kOpSpecConstantLiteralInOperandIndex)
.words != bit_pattern) {
spec_inst->SetInOperand(kOpSpecConstantLiteralInOperandIndex,
std::move(bit_pattern));
modified = true;
}
break;
case spv::Op::OpSpecConstantTrue:
// If the new value is also 'true', no need to change anything.
// Otherwise, set the opcode to OpSpecConstantFalse;
if (!static_cast<bool>(bit_pattern.front())) {
spec_inst->SetOpcode(spv::Op::OpSpecConstantFalse);
modified = true;
}
break;
case spv::Op::OpSpecConstantFalse:
// If the new value is also 'false', no need to change anything.
// Otherwise, set the opcode to OpSpecConstantTrue;
if (static_cast<bool>(bit_pattern.front())) {
spec_inst->SetOpcode(spv::Op::OpSpecConstantTrue);
modified = true;
}
break;
default:
break;
}
// No need to update the DefUse manager, as this pass does not change any
// ids.
}
return modified ? Status::SuccessWithChange : Status::SuccessWithoutChange;
}
// Returns true if the given char is ':', '\0' or considered as blank space
// (i.e.: '\n', '\r', '\v', '\t', '\f' and ' ').
bool IsSeparator(char ch) {
return std::strchr(":\0", ch) || std::isspace(ch) != 0;
}
std::unique_ptr<SetSpecConstantDefaultValuePass::SpecIdToValueStrMap>
SetSpecConstantDefaultValuePass::ParseDefaultValuesString(const char* str) {
if (!str) return nullptr;
auto spec_id_to_value = MakeUnique<SpecIdToValueStrMap>();
// The parsing loop, break when points to the end.
while (*str) {
// Find the spec id.
while (std::isspace(*str)) str++; // skip leading spaces.
const char* entry_begin = str;
while (!IsSeparator(*str)) str++;
const char* entry_end = str;
std::string spec_id_str(entry_begin, entry_end - entry_begin);
uint32_t spec_id = 0;
if (!ParseNumber(spec_id_str.c_str(), &spec_id)) {
// The spec id is not a valid uint32 number.
return nullptr;
}
auto iter = spec_id_to_value->find(spec_id);
if (iter != spec_id_to_value->end()) {
// Same spec id has been defined before
return nullptr;
}
// Find the ':', spaces between the spec id and the ':' are not allowed.
if (*str++ != ':') {
// ':' not found
return nullptr;
}
// Find the value string
const char* val_begin = str;
while (!IsSeparator(*str)) str++;
const char* val_end = str;
if (val_end == val_begin) {
// Value string is empty.
return nullptr;
}
// Update the mapping with spec id and value string.
(*spec_id_to_value)[spec_id] = std::string(val_begin, val_end - val_begin);
// Skip trailing spaces.
while (std::isspace(*str)) str++;
}
return spec_id_to_value;
}
} // namespace opt
} // namespace spvtools