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// Copyright 2020 The Tint Authors.
//
// 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.
#ifndef SRC_TINT_LANG_SPIRV_READER_FUNCTION_H_
#define SRC_TINT_LANG_SPIRV_READER_FUNCTION_H_
#include <limits>
#include <memory>
#include <optional>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include "src/tint/lang/spirv/reader/attributes.h"
#include "src/tint/lang/spirv/reader/construct.h"
#include "src/tint/lang/spirv/reader/parser_impl.h"
#include "src/tint/lang/wgsl/program/program_builder.h"
#include "src/tint/utils/text/string_stream.h"
namespace tint::reader::spirv {
/// Kinds of CFG edges.
//
// The edge kinds are used in many ways.
//
// For example, consider the edges leaving a basic block and going to distinct targets. If the
// total number of kForward + kIfBreak + kCaseFallThrough edges is more than 1, then the block must
// be a structured header, i.e. it needs a merge instruction to declare the control flow divergence
// and associated reconvergence point. Those those edge kinds count toward divergence because
// SPIR-V is designed to easily map back to structured control flow in GLSL (and C). In GLSL and C,
// those forward-flow edges don't have a special statement to express them. The other forward
// edges: kSwitchBreak, kLoopBreak, and kLoopContinue directly map to 'break', 'break', and
// 'continue', respectively.
enum class EdgeKind {
// A back-edge: An edge from a node to one of its ancestors in a depth-first
// search from the entry block.
kBack,
// An edge from a node to the merge block of the nearest enclosing switch,
// where there is no intervening loop.
kSwitchBreak,
// An edge from a node to the merge block of the nearest enclosing loop, where
// there is no intervening switch.
// The source block is a "break block" as defined by SPIR-V.
kLoopBreak,
// An edge from a node in a loop body to the associated continue target, where
// there are no other intervening loops or switches.
// The source block is a "continue block" as defined by SPIR-V.
kLoopContinue,
// An edge from a node to the merge block of the nearest enclosing structured
// construct, but which is neither a kSwitchBreak or a kLoopBreak.
// This can only occur for an "if" selection, i.e. where the selection
// header ends in OpBranchConditional.
kIfBreak,
// An edge from one switch case to the next sibling switch case. Note, this is not valid in WGSL
// at the moment and will trigger an ICE if encountered. It is here for completeness.
kCaseFallThrough,
// None of the above.
kForward
};
/// The number used to represent an invalid block position
static constexpr uint32_t kInvalidBlockPos = ~0u;
/// Bookkeeping info for a basic block.
struct BlockInfo {
/// Constructor
/// @param bb internal representation of the basic block
explicit BlockInfo(const spvtools::opt::BasicBlock& bb);
~BlockInfo();
/// The internal representation of the basic block.
const spvtools::opt::BasicBlock* basic_block;
/// The ID of the OpLabel instruction that starts this block.
uint32_t id = 0;
/// The position of this block in the reverse structured post-order.
/// If the block is not in that order, then this remains the invalid value.
uint32_t pos = kInvalidBlockPos;
/// If this block is a header, then this is the ID of the merge block.
uint32_t merge_for_header = 0;
/// If this block is a loop header, then this is the ID of the continue
/// target.
uint32_t continue_for_header = 0;
/// If this block is a merge, then this is the ID of the header.
uint32_t header_for_merge = 0;
/// If this block is a continue target, then this is the ID of the loop
/// header.
uint32_t header_for_continue = 0;
/// Is this block a continue target which is its own loop header block?
/// In this case the continue construct is the entire loop. The associated
/// "loop construct" is empty, and not represented.
bool is_continue_entire_loop = false;
/// The immediately enclosing structured construct. If this block is not
/// in the block order at all, then this is still nullptr.
const Construct* construct = nullptr;
/// Maps the ID of a successor block (in the CFG) to its edge classification.
std::unordered_map<uint32_t, EdgeKind> succ_edge;
/// The following fields record relationships among blocks in a selection
/// construct for an OpSwitch instruction.
/// If not null, then the pointed-at construct is a selection for an OpSwitch,
/// and this block is a case target for it. We say this block "heads" the
/// case construct.
const Construct* case_head_for = nullptr;
/// If not null, then the pointed-at construct is a selection for an OpSwitch,
/// and this block is the default target for it. We say this block "heads"
/// the default case construct.
const Construct* default_head_for = nullptr;
/// Is this a default target for a switch, and is it also the merge for its
/// switch?
bool default_is_merge = false;
/// The list of switch values that cause a branch to this block.
std::optional<utils::Vector<uint64_t, 4>> case_values;
/// The following fields record relationships among blocks in a selection
/// construct for an OpBranchConditional instruction.
/// When this block is an if-selection header, this is the edge kind
/// for the true branch.
EdgeKind true_kind = EdgeKind::kForward;
/// When this block is an if-selection header, this is the edge kind
/// for the false branch.
EdgeKind false_kind = EdgeKind::kForward;
/// If not 0, then this block is an if-selection header, and `true_head` is
/// the target id of the true branch on the OpBranchConditional, and that
/// target is inside the if-selection.
uint32_t true_head = 0;
/// If not 0, then this block is an if-selection header, and `false_head`
/// is the target id of the false branch on the OpBranchConditional, and
/// that target is inside the if-selection.
uint32_t false_head = 0;
/// If not 0, then this block is an if-selection header, and when following
/// the flow via the true and false branches, control first reconverges at
/// the block with ID `premerge_head`, and `premerge_head` is still inside
/// the if-selection.
uint32_t premerge_head = 0;
/// If non-empty, then this block is an if-selection header, and control flow
/// in the body must be guarded by a boolean flow variable with this name.
/// This occurs when a block in this selection has both an if-break edge, and
/// also a different normal forward edge but without a merge instruction.
std::string flow_guard_name = "";
/// The result IDs that this block is responsible for declaring as a
/// hoisted variable.
/// @see DefInfo#requires_hoisted_var_def
utils::Vector<uint32_t, 4> hoisted_ids;
/// A PhiAssignment represents the assignment of a value to the state
/// variable associated with an OpPhi in a successor block.
struct PhiAssignment {
/// The ID of an OpPhi receiving a value from this basic block.
uint32_t phi_id;
/// The ID of the value carried to the given OpPhi.
uint32_t value_id;
};
/// If this basic block branches to a visited basic block containing phis,
/// then this is the list of writes to the variables associated those phis.
utils::Vector<PhiAssignment, 4> phi_assignments;
/// The IDs of OpPhi instructions which require their associated state
/// variable to be declared in this basic block.
utils::Vector<uint32_t, 4> phis_needing_state_vars;
};
/// Writes the BlockInfo to the stream
/// @param o the stream
/// @param bi the BlockInfo
/// @returns the stream so calls can be chained
inline utils::StringStream& operator<<(utils::StringStream& o, const BlockInfo& bi) {
o << "BlockInfo{"
<< " id: " << bi.id << " pos: " << bi.pos << " merge_for_header: " << bi.merge_for_header
<< " continue_for_header: " << bi.continue_for_header
<< " header_for_merge: " << bi.header_for_merge
<< " is_continue_entire_loop: " << int(bi.is_continue_entire_loop) << "}";
return o;
}
/// Reasons for avoiding generating an intermediate value.
enum class SkipReason {
/// `kDontSkip`: The value should be generated. Used for most values.
kDontSkip,
/// For remaining cases, the value is not generated.
/// `kOpaqueObject`: used for any intermediate value which is an sampler,
/// image,
/// or sampled image, or any pointer to such object. Code is generated
/// for those objects only when emitting the image instructions that access
/// the image (read, write, sample, gather, fetch, or query). For example,
/// when encountering an OpImageSampleExplicitLod, a call to the
/// textureSampleLevel builtin function will be emitted, and the call will
/// directly reference the underlying texture and sampler (variable or
/// function parameter).
kOpaqueObject,
/// `kSinkPointerIntoUse`: used to avoid emitting certain pointer expressions,
/// by instead generating their reference expression directly at the point of
/// use. For example, we apply this to OpAccessChain when indexing into a
/// vector, to avoid generating address-of vector component expressions.
kSinkPointerIntoUse,
/// `kPointSizeBuiltinPointer`: the value is a pointer to the Position builtin
/// variable. Don't generate its address. Avoid generating stores to this
/// pointer.
kPointSizeBuiltinPointer,
/// `kPointSizeBuiltinValue`: the value is the value loaded from the
/// PointSize builtin. Use 1.0f instead, because that's the only value
/// supported by WebGPU.
kPointSizeBuiltinValue,
/// `kSampleMaskInBuiltinPointer`: the value is a pointer to the SampleMaskIn
/// builtin input variable. Don't generate its address.
kSampleMaskInBuiltinPointer,
/// `kSampleMaskOutBuiltinPointer`: the value is a pointer to the SampleMask
/// builtin output variable.
kSampleMaskOutBuiltinPointer,
};
/// Bookkeeping info for a SPIR-V ID defined in the function, or some
/// module-scope variables. This will be valid for result IDs that are:
/// - defined in the function and:
/// - instructions that are not OpLabel, and not OpFunctionParameter
/// - are defined in a basic block visited in the block-order for the
/// function.
/// - certain module-scope builtin variables.
struct DefInfo {
/// Constructor for a locally defined value.
/// @param index an ordering index for uniqueness.
/// @param def_inst the SPIR-V instruction defining the ID
/// @param block_pos the position of the first basic block dominated by the
/// definition
DefInfo(size_t index, const spvtools::opt::Instruction& def_inst, uint32_t block_pos);
/// Constructor for a value defined at module scope.
/// @param index an ordering index for uniqueness.
/// @param def_inst the SPIR-V instruction defining the ID
DefInfo(size_t index, const spvtools::opt::Instruction& def_inst);
/// Destructor.
~DefInfo();
/// An index for uniquely and deterministically ordering all DefInfo records
/// in a function.
const size_t index = 0;
/// The SPIR-V instruction that defines the ID.
const spvtools::opt::Instruction& inst;
/// Information about a definition created inside a function.
struct Local {
/// Constructor.
/// @param block_pos the position of the basic block defining the value.
explicit Local(uint32_t block_pos);
/// Copy constructor.
/// @param other the original object to copy from.
Local(const Local& other);
/// Destructor.
~Local();
/// The position of the basic block defininig the value, in function
/// block order.
/// See method `FunctionEmitter::ComputeBlockOrderAndPositions` for block
/// ordering.
const uint32_t block_pos = 0;
/// The number of uses of this ID.
uint32_t num_uses = 0;
/// The block position of the first use of this ID, or MAX_UINT if it is not
/// used at all. The "first" ordering is determined by the function block
/// order. The first use of an ID might be in an OpPhi that precedes the
/// definition of the ID.
/// The ID defined by an OpPhi is counted as being "used" in each of its
/// parent blocks.
uint32_t first_use_pos = std::numeric_limits<uint32_t>::max();
/// The block position of the last use of this ID, or 0 if it is not used
/// at all. The "last" ordering is determined by the function block order.
/// The ID defined by an OpPhi is counted as being "used" in each of its
/// parent blocks.
uint32_t last_use_pos = 0;
/// Is this value used in a construct other than the one in which it was
/// defined?
bool used_in_another_construct = false;
/// Is this ID an OpPhi?
bool is_phi = false;
};
/// Information about a definition inside the function. Populated if and only
/// if the definition actually is inside the function.
std::optional<Local> local;
/// True if this ID requires a WGSL 'let' definition, due to context. It
/// might get one anyway (so this is *not* an if-and-only-if condition).
bool requires_named_let_def = false;
/// True if this ID must map to a WGSL variable declaration before the
/// corresponding position of the ID definition in SPIR-V. This compensates
/// for the difference between dominance and scoping. An SSA definition can
/// dominate all its uses, but the construct where it is defined does not
/// enclose all the uses, and so if it were declared as a WGSL let-
/// declaration at the point of its SPIR-V definition, then the WGSL name
/// would go out of scope too early. Fix that by creating a variable at the
/// top of the smallest construct that encloses both the definition and all
/// its uses. Then the original SPIR-V definition maps to a WGSL assignment
/// to that variable, and each SPIR-V use becomes a WGSL read from the
/// variable.
/// TODO(dneto): This works for constants of storable type, but not, for
/// example, pointers. crbug.com/tint/98
bool requires_hoisted_var_def = false;
/// Information about a pointer value, used to construct its WGSL type.
struct Pointer {
/// The address space to use for this value, if it is of pointer type.
/// This is required to carry an address space override from a storage
/// buffer expressed in the old style (with Uniform address space)
/// that needs to be remapped to StorageBuffer address space.
/// This is kInvalid for non-pointers.
builtin::AddressSpace address_space = builtin::AddressSpace::kUndefined;
/// The declared access mode.
builtin::Access access = builtin::Access::kUndefined;
};
/// The expression to use when sinking pointers into their use.
/// When encountering a use of this instruction, we will emit this expression
/// instead.
TypedExpression sink_pointer_source_expr = {};
/// Collected information about a pointer value.
Pointer pointer;
/// The reason, if any, that this value should be ignored.
/// Normally no values are ignored. This field can be updated while
/// generating code because sometimes we only discover necessary facts
/// in the middle of generating code.
SkipReason skip = SkipReason::kDontSkip;
};
/// Writes the DefInfo to the stream
/// @param o the stream
/// @param di the DefInfo
/// @returns the stream so calls can be chained
inline utils::StringStream& operator<<(utils::StringStream& o, const DefInfo& di) {
o << "DefInfo{"
<< " inst.result_id: " << di.inst.result_id();
if (di.local.has_value()) {
const auto& dil = di.local.value();
o << " block_pos: " << dil.block_pos << " num_uses: " << dil.num_uses
<< " first_use_pos: " << dil.first_use_pos << " last_use_pos: " << dil.last_use_pos
<< " used_in_another_construct: " << (dil.used_in_another_construct ? "true" : "false")
<< " is_phi: " << (dil.is_phi ? "true" : "false") << "";
}
o << " requires_named_let_def: " << (di.requires_named_let_def ? "true" : "false")
<< " requires_hoisted_var_def: " << (di.requires_hoisted_var_def ? "true" : "false");
if (di.pointer.address_space != builtin::AddressSpace::kUndefined) {
o << " sc:" << int(di.pointer.address_space);
}
switch (di.skip) {
case SkipReason::kDontSkip:
break;
case SkipReason::kOpaqueObject:
o << " skip:opaque";
break;
case SkipReason::kSinkPointerIntoUse:
o << " skip:sink_pointer";
break;
case SkipReason::kPointSizeBuiltinPointer:
o << " skip:pointsize_pointer";
break;
case SkipReason::kPointSizeBuiltinValue:
o << " skip:pointsize_value";
break;
case SkipReason::kSampleMaskInBuiltinPointer:
o << " skip:samplemaskin_pointer";
break;
case SkipReason::kSampleMaskOutBuiltinPointer:
o << " skip:samplemaskout_pointer";
break;
}
o << "}";
return o;
}
/// A placeholder Statement that exists for the duration of building a
/// StatementBlock. Once the StatementBlock is built, Build() will be called to
/// construct the final AST node, which will be used in the place of this
/// StatementBuilder.
/// StatementBuilders are used to simplify construction of AST nodes that will
/// become immutable. The builders may hold mutable state while the
/// StatementBlock is being constructed, which becomes an immutable node on
/// StatementBlock::Finalize().
class StatementBuilder : public utils::Castable<StatementBuilder, ast::Statement> {
public:
/// Constructor
StatementBuilder() : Base(GenerationID(), ast::NodeID(), Source{}) {}
/// @param builder the program builder
/// @returns the build AST node
virtual const ast::Statement* Build(ProgramBuilder* builder) const = 0;
private:
Node* Clone(CloneContext*) const override;
};
/// A FunctionEmitter emits a SPIR-V function onto a Tint AST module.
class FunctionEmitter {
using StructMemberList = utils::Vector<const ast::StructMember*, 8>;
using ExpressionList = utils::Vector<const ast::Expression*, 8>;
using ParameterList = utils::Vector<const ast::Parameter*, 8>;
using StatementList = utils::Vector<const ast::Statement*, 8>;
public:
/// Creates a FunctionEmitter, and prepares to write to the AST module
/// in `pi`
/// @param pi a ParserImpl which has already executed BuildInternalModule
/// @param function the function to emit
FunctionEmitter(ParserImpl* pi, const spvtools::opt::Function& function);
/// Creates a FunctionEmitter, and prepares to write to the AST module
/// in `pi`
/// @param pi a ParserImpl which has already executed BuildInternalModule
/// @param function the function to emit
/// @param ep_info entry point information for this function, or nullptr
FunctionEmitter(ParserImpl* pi,
const spvtools::opt::Function& function,
const EntryPointInfo* ep_info);
/// Move constructor. Only valid when the other object was newly created.
/// @param other the emitter to clone
FunctionEmitter(FunctionEmitter&& other);
/// Destructor
~FunctionEmitter();
/// Emits the function to AST module.
/// @return whether emission succeeded
bool Emit();
/// @returns true if emission has not yet failed.
bool success() const { return fail_stream_.status(); }
/// @returns true if emission has failed.
bool failed() const { return !success(); }
/// Finalizes any StatementBuilders returns the body of the function.
/// Must only be called once, and to be used only for testing.
/// @returns the body of the function.
StatementList ast_body();
/// Records failure.
/// @returns a FailStream on which to emit diagnostics.
FailStream& Fail() { return fail_stream_.Fail(); }
/// @returns the parser implementation
ParserImpl* parser() { return &parser_impl_; }
/// Emits the entry point as a wrapper around its implementation function.
/// Pipeline inputs become formal parameters, and pipeline outputs become
/// return values.
/// @returns false if emission failed.
bool EmitEntryPointAsWrapper();
/// Creates one or more entry point input parameters corresponding to a part of an input
/// variable. The part of the input variable is specfied by the `index_prefix`, which
/// successively indexes into the variable. Also generates the assignment statements that copy
/// the input parameter to the corresponding part of the variable. Assumes the variable has
/// already been created in the Private address space.
/// @param var_name The name of the variable
/// @param var_type The store type of the variable
/// @param attributes The variable's attributes
/// @param index_prefix Indices stepping into the variable, indicating what part of the variable
/// to populate.
/// @param tip_type The type of the component inside variable, after indexing with the indices
/// in `index_prefix`.
/// @param forced_param_type The type forced by WGSL, if the variable is a builtin, otherwise
/// the same as var_type.
/// @param params The parameter list where the new parameter is appended.
/// @param statements The statement list where the assignment is appended.
/// @returns false if emission failed
bool EmitPipelineInput(std::string var_name,
const Type* var_type,
utils::Vector<int, 8> index_prefix,
const Type* tip_type,
const Type* forced_param_type,
Attributes& attributes,
ParameterList& params,
StatementList& statements);
/// Creates one or more struct members from an output variable, and the
/// expressions that compute the value they contribute to the entry point
/// return value. The part of the output variable is specfied
/// by the `index_prefix`, which successively indexes into the variable.
/// Assumes the variable has already been created in the Private address space
/// @param var_name The name of the variable
/// @param var_type The store type of the variable
/// @param index_prefix Indices stepping into the variable, indicating what part of the variable
/// to populate.
/// @param tip_type The type of the component inside variable, after indexing with the indices
/// in `index_prefix`.
/// @param forced_member_type The type forced by WGSL, if the variable is a builtin, otherwise
/// the same as var_type.
/// @param attributes The variable's attributes
/// @param return_members The struct member list where the new member is added.
/// @param return_exprs The expression list where the return expression is added.
/// @returns false if emission failed
bool EmitPipelineOutput(std::string var_name,
const Type* var_type,
utils::Vector<int, 8> index_prefix,
const Type* tip_type,
const Type* forced_member_type,
Attributes& attributes,
StructMemberList& return_members,
ExpressionList& return_exprs);
/// Updates the attribute list, replacing an existing Location attribute
/// with another having one higher location value. Does nothing if no
/// location attribute exists.
/// Assumes the list contains at most one Location attribute.
/// @param attributes the attribute list to modify
void IncrementLocation(Attributes& attributes);
/// Create an ast::BlockStatement representing the body of the function.
/// This creates the statement stack, which is non-empty for the lifetime
/// of the function.
/// @returns the body of the function, or null on error
const ast::BlockStatement* MakeFunctionBody();
/// Emits the function body, populating the bottom entry of the statements
/// stack.
/// @returns false if emission failed.
bool EmitBody();
/// Records a mapping from block ID to a BlockInfo struct.
/// Populates `block_info_`
void RegisterBasicBlocks();
/// Verifies that terminators only branch to labels in the current function.
/// Assumes basic blocks have been registered.
/// @returns true if terminators are valid
bool TerminatorsAreValid();
/// Populates merge-header cross-links and BlockInfo#is_continue_entire_loop.
/// Also verifies that merge instructions go to blocks in the same function.
/// Assumes basic blocks have been registered, and terminators are valid.
/// @returns false if registration fails
bool RegisterMerges();
/// Determines the output order for the basic blocks in the function.
/// Populates `block_order_` and BlockInfo#pos.
/// Assumes basic blocks have been registered.
void ComputeBlockOrderAndPositions();
/// @returns the reverse structured post order of the basic blocks in
/// the function.
const std::vector<uint32_t>& block_order() const { return block_order_; }
/// Verifies that the orderings among a structured header, continue target,
/// and merge block are valid. Assumes block order has been computed, and
/// merges are valid and recorded.
/// @returns false if invalid nesting was detected
bool VerifyHeaderContinueMergeOrder();
/// Labels each basic block with its nearest enclosing structured construct.
/// Populates BlockInfo#construct and the `constructs_` list.
/// Assumes terminators are valid and merges have been registered, block
/// order has been computed, and each block is labeled with its position.
/// Checks nesting of structured control flow constructs.
/// @returns false if bad nesting has been detected
bool LabelControlFlowConstructs();
/// @returns the structured constructs
const ConstructList& constructs() const { return constructs_; }
/// Marks blocks targets of a switch, either as the head of a case or
/// as the default target.
/// @returns false on failure
bool FindSwitchCaseHeaders();
/// Classifies the successor CFG edges for the ordered basic blocks.
/// Also checks validity of each edge (populates BlockInfo#succ_edge).
/// Implicitly checks dominance rules for headers and continue constructs.
/// Assumes each block has been labeled with its control flow construct.
/// @returns false on failure
bool ClassifyCFGEdges();
/// Marks the blocks within a selection construct that are the first blocks
/// in the "then" clause, the "else" clause, and the "premerge" clause.
/// The head of the premerge clause is the block, if it exists, at which
/// control flow reconverges from the "then" and "else" clauses, but before
/// before the merge block for that selection. The existence of a premerge
/// should be an exceptional case, but is allowed by the structured control
/// flow rules.
/// @returns false if bad nesting has been detected.
bool FindIfSelectionInternalHeaders();
/// Creates a DefInfo record for each module-scope builtin variable
/// that should be handled specially. Either it's ignored, or its store
/// type is converted on load.
/// Populates the `def_info_` mapping for such IDs.
/// @returns false on failure
bool RegisterSpecialBuiltInVariables();
/// Creates a DefInfo record for each locally defined SPIR-V ID.
/// Populates the `def_info_` mapping with basic results for such IDs.
/// @returns false on failure
bool RegisterLocallyDefinedValues();
/// Returns the pointer information needed for the given SPIR-V ID.
/// Assumes the given ID yields a value of pointer type. For IDs
/// corresponding to WGSL root identifiers (i.e. OpVariable or
/// OpFunctionParameter), the info is computed from scratch.
/// Otherwise, this looks up pointer info from a base pointer whose
/// data is cached in def_info_.
/// @param id a SPIR-V ID for a pointer value
/// @returns the associated Pointer info
DefInfo::Pointer GetPointerInfo(uint32_t id);
/// Remaps the address space and access mode for the type of a
/// locally-defined value, if necessary. If it's not a pointer or reference
/// type, then the result is a copy of the `type` argument.
/// @param type the AST type
/// @param result_id the SPIR-V ID for the locally defined value
/// @returns an possibly updated type
const Type* RemapPointerProperties(const Type* type, uint32_t result_id);
/// Marks locally defined values when they should get a 'let'
/// definition in WGSL, or a 'var' definition at an outer scope.
/// This occurs in several cases:
/// - When a SPIR-V instruction might use the dynamically computed value
/// only once, but the WGSL code might reference it multiple times.
/// For example, this occurs for the vector operands of OpVectorShuffle.
/// In this case the definition's DefInfo#requires_named_let_def property
/// is set to true.
/// - When a definition and at least one of its uses are not in the
/// same structured construct.
/// In this case the definition's DefInfo#requires_named_let_def property
/// is set to true.
/// - When a definition is in a construct that does not enclose all the
/// uses. In this case the definition's DefInfo#requires_hoisted_var_def
/// property is set to true.
/// Updates the `def_info_` mapping.
void FindValuesNeedingNamedOrHoistedDefinition();
/// Emits declarations of function variables.
/// @returns false if emission failed.
bool EmitFunctionVariables();
/// Emits statements in the body.
/// @returns false if emission failed.
bool EmitFunctionBodyStatements();
/// Emits a basic block.
/// @param block_info the block to emit
/// @returns false if emission failed.
bool EmitBasicBlock(const BlockInfo& block_info);
/// Emits an IfStatement, including its condition expression, and sets
/// up the statement stack to accumulate subsequent basic blocks into
/// the "then" and "else" clauses.
/// @param block_info the if-selection header block
/// @returns false if emission failed.
bool EmitIfStart(const BlockInfo& block_info);
/// Emits a SwitchStatement, including its condition expression, and sets
/// up the statement stack to accumulate subsequent basic blocks into
/// the default clause and case clauses.
/// @param block_info the switch-selection header block
/// @returns false if emission failed.
bool EmitSwitchStart(const BlockInfo& block_info);
/// Emits a LoopStatement, and pushes a new StatementBlock to accumulate
/// the remaining instructions in the current block and subsequent blocks
/// in the loop.
/// @param construct the loop construct
/// @returns false if emission failed.
bool EmitLoopStart(const Construct* construct);
/// Emits a ContinuingStatement, and pushes a new StatementBlock to accumulate
/// the remaining instructions in the current block and subsequent blocks
/// in the continue construct.
/// @param construct the continue construct
/// @returns false if emission failed.
bool EmitContinuingStart(const Construct* construct);
/// Emits the non-control-flow parts of a basic block, but only once.
/// The `already_emitted` parameter indicates whether the code has already
/// been emitted, and is used to signal that this invocation actually emitted
/// it.
/// @param block_info the block to emit
/// @param already_emitted the block to emit
/// @returns false if the code had not yet been emitted, but emission failed
bool EmitStatementsInBasicBlock(const BlockInfo& block_info, bool* already_emitted);
/// Emits code for terminators, but that aren't part of entering or
/// resolving structured control flow. That is, if the basic block
/// terminator calls for it, emit the fallthrough break, continue, return, or kill commands.
/// @param block_info the block with the terminator to emit (if any)
/// @returns false if emission failed
bool EmitNormalTerminator(const BlockInfo& block_info);
/// Returns a new statement to represent the given branch representing a
/// "normal" terminator, as in the sense of EmitNormalTerminator. If no
/// WGSL statement is required, the statement will be nullptr. This method
/// tries to avoid emitting a 'break' statement when that would be redundant
/// in WGSL due to implicit breaking out of a switch.
/// @param src_info the source block
/// @param dest_info the destination block
/// @returns the new statement, or a null statement
const ast::Statement* MakeBranch(const BlockInfo& src_info, const BlockInfo& dest_info) {
return MakeBranchDetailed(src_info, dest_info, nullptr);
}
/// Returns a new statement to represent the given branch representing a
/// "normal" terminator, as in the sense of EmitNormalTerminator. If no
/// WGSL statement is required, the statement will be nullptr. This method tries to avoid
/// emitting a 'break' statement when that would be redundant in WGSL due to implicit breaking
/// out of a switch. If the control flow edge is an if-break for an if-selection with a
/// control flow guard, then return that guard name via `flow_guard_name_ptr`
/// when that parameter is not null.
/// @param src_info the source block
/// @param dest_info the destination block
/// @param flow_guard_name_ptr return parameter for control flow guard name
/// @returns the new statement, or a null statement
const ast::Statement* MakeBranchDetailed(const BlockInfo& src_info,
const BlockInfo& dest_info,
std::string* flow_guard_name_ptr);
/// Returns a new if statement with the given statements as the then-clause
/// and the else-clause. Either or both clauses might be nullptr. If both
/// are nullptr, then don't make a new statement and instead return nullptr.
/// @param condition the branching condition
/// @param then_stmt the statement for the then clause of the if, or nullptr
/// @param else_stmt the statement for the else clause of the if, or nullptr
/// @returns the new statement, or nullptr
const ast::Statement* MakeSimpleIf(const ast::Expression* condition,
const ast::Statement* then_stmt,
const ast::Statement* else_stmt) const;
/// Emits the statements for an normal-terminator OpBranchConditional
/// where one branch is a case fall through (the true branch if and only
/// if `fall_through_is_true_branch` is true), and the other branch is
/// goes to a different destination, named by `other_dest`.
/// @param src_info the basic block from which we're branching
/// @param cond the branching condition
/// @param other_edge_kind the edge kind from the source block to the other
/// destination
/// @param other_dest the other branching destination
/// @param fall_through_is_true_branch true when the fall-through is the true
/// branch
/// @returns the false if emission fails
bool EmitConditionalCaseFallThrough(const BlockInfo& src_info,
const ast::Expression* cond,
EdgeKind other_edge_kind,
const BlockInfo& other_dest,
bool fall_through_is_true_branch);
/// Emits a normal instruction: not a terminator, label, or variable
/// declaration.
/// @param inst the instruction
/// @returns false if emission failed.
bool EmitStatement(const spvtools::opt::Instruction& inst);
/// Emits a const definition for the typed value in `ast_expr`, and
/// records it as the translation for the result ID from `inst`.
/// @param inst the SPIR-V instruction defining the value
/// @param ast_expr the already-computed AST expression for the value
/// @returns false if emission failed.
bool EmitConstDefinition(const spvtools::opt::Instruction& inst, TypedExpression ast_expr);
/// Emits a write of the typed value in `ast_expr` to a hoisted variable
/// for the given SPIR-V ID, if that ID has a hoisted declaration. Otherwise,
/// emits a const definition instead.
/// @param inst the SPIR-V instruction defining the value
/// @param ast_expr the already-computed AST expression for the value
/// @returns false if emission failed.
bool EmitConstDefOrWriteToHoistedVar(const spvtools::opt::Instruction& inst,
TypedExpression ast_expr);
/// If the result ID of the given instruction is hoisted, then emits
/// a statement to write the expression to the hoisted variable, and
/// returns true. Otherwise return false.
/// @param inst the SPIR-V instruction defining a value.
/// @param ast_expr the expression to assign.
/// @returns true if the instruction has an associated hoisted variable.
bool WriteIfHoistedVar(const spvtools::opt::Instruction& inst, TypedExpression ast_expr);
/// Makes an expression from a SPIR-V ID.
/// if the SPIR-V result type is a pointer.
/// @param id the SPIR-V ID of the value
/// @returns an AST expression for the instruction, or an invalid
/// TypedExpression on error.
TypedExpression MakeExpression(uint32_t id);
/// Creates an expression and supporting statements for a combinatorial
/// instruction, or returns null. A SPIR-V instruction is combinatorial
/// if it has no side effects and its result depends only on its operands,
/// and not on accessing external state like memory or the state of other
/// invocations. Statements are only created if required to provide values
/// to the expression. Supporting statements are not required to be
/// combinatorial.
/// @param inst a SPIR-V instruction representing an exrpression
/// @returns an AST expression for the instruction, or nullptr.
TypedExpression MaybeEmitCombinatorialValue(const spvtools::opt::Instruction& inst);
/// Creates an expression and supporting statements for the a GLSL.std.450
/// extended instruction.
/// @param inst a SPIR-V OpExtInst instruction from GLSL.std.450
/// @returns an AST expression for the instruction, or nullptr.
TypedExpression EmitGlslStd450ExtInst(const spvtools::opt::Instruction& inst);
/// Creates an expression for the GLSL.std.450 matrix `inverse` extended instruction.
/// @param inst a SPIR-V OpExtInst instruction from GLSL.std.450
/// @returns an AST expression for the instruction, or nullptr.
TypedExpression EmitGlslStd450MatrixInverse(const spvtools::opt::Instruction& inst);
/// Creates an expression for OpCompositeExtract
/// @param inst an OpCompositeExtract instruction.
/// @returns an AST expression for the instruction, or nullptr.
TypedExpression MakeCompositeExtract(const spvtools::opt::Instruction& inst);
/// Creates an expression for indexing into a composite value. The literal
/// indices that step into the value start at instruction input operand
/// `start_index` and run to the end of the instruction.
/// @param inst the original instruction
/// @param composite the typed expression for the composite
/// @param composite_type_id the SPIR-V type ID for the composite
/// @param index_start the index of the first operand in `inst` that is an
/// index into the composite type
/// @returns an AST expression for the decomposed composite, or {} on error
TypedExpression MakeCompositeValueDecomposition(const spvtools::opt::Instruction& inst,
TypedExpression composite,
uint32_t composite_type_id,
int index_start);
/// Creates an expression for OpVectorShuffle
/// @param inst an OpVectorShuffle instruction.
/// @returns an AST expression for the instruction, or nullptr.
TypedExpression MakeVectorShuffle(const spvtools::opt::Instruction& inst);
/// Creates an expression for a numeric conversion.
/// @param inst a numeric conversion instruction
/// @returns an AST expression for the instruction, or nullptr.
TypedExpression MakeNumericConversion(const spvtools::opt::Instruction& inst);
/// Gets the block info for a block ID, if any exists
/// @param id the SPIR-V ID of the OpLabel instruction starting the block
/// @returns the block info for the given ID, if it exists, or nullptr
BlockInfo* GetBlockInfo(uint32_t id) const {
auto where = block_info_.find(id);
if (where == block_info_.end()) {
return nullptr;
}
return where->second.get();
}
/// Is the block, represented by info, in the structured block order?
/// @param info the block
/// @returns true if the block is in the structured block order.
bool IsInBlockOrder(const BlockInfo* info) const {
return info && info->pos != kInvalidBlockPos;
}
/// Gets the definition info for a result ID.
/// @param id the SPIR-V ID of local definition.
/// @returns the definition info for the given ID, if it exists, or nullptr
DefInfo* GetDefInfo(uint32_t id) const {
auto where = def_info_.find(id);
if (where == def_info_.end()) {
return nullptr;
}
return where->second.get();
}
/// Returns the skip reason for a result ID.
/// @param id SPIR-V result ID
/// @returns the skip reason for the given ID, or SkipReason::kDontSkip
SkipReason GetSkipReason(uint32_t id) const {
if (auto* def_info = GetDefInfo(id)) {
return def_info->skip;
}
return SkipReason::kDontSkip;
}
/// Returns the most deeply nested structured construct which encloses the
/// WGSL scopes of names declared in both block positions. Each position must
/// be a valid index into the function block order array.
/// @param first_pos the first block position
/// @param last_pos the last block position
/// @returns the smallest construct containing both positions
const Construct* GetEnclosingScope(uint32_t first_pos, uint32_t last_pos) const;
/// Finds loop construct associated with a continue construct, if it exists.
/// Returns nullptr if:
/// - the given construct is not a continue construct
/// - the continue construct does not have an associated loop construct
/// (the continue target is also the loop header block)
/// @param c the continue construct
/// @returns the associated loop construct, or nullptr
const Construct* SiblingLoopConstruct(const Construct* c) const;
/// Returns an identifier expression for the swizzle name of the given
/// index into a vector. Emits an error and returns nullptr if the
/// index is out of range, i.e. 4 or higher.
/// @param i index of the subcomponent
/// @returns the identifier expression for the `i`'th component
const ast::Identifier* Swizzle(uint32_t i);
/// Returns an identifier expression for the swizzle name of the first
/// `n` elements of a vector. Emits an error and returns nullptr if `n`
/// is out of range, i.e. 4 or higher.
/// @param n the number of components in the swizzle
/// @returns the swizzle identifier for the first n elements of a vector
const ast::Identifier* PrefixSwizzle(uint32_t n);
/// Converts SPIR-V image coordinates from an image access instruction
/// (e.g. OpImageSampledImplicitLod) into an expression list consisting of
/// the texture coordinates, and an integral array index if the texture is
/// arrayed. The texture coordinate is a scalar for 1D textures, a vector of
/// 2 elements for a 2D texture, and a vector of 3 elements for a 3D or
/// Cube texture. Excess components are ignored, e.g. if the SPIR-V
/// coordinate is a 4-element vector but the image is a 2D non-arrayed
/// texture then the 3rd and 4th components are ignored.
/// On failure, issues an error and returns an empty expression list.
/// @param image_access the image access instruction
/// @returns an ExpressionList of the coordinate and array index (if any)
ExpressionList MakeCoordinateOperandsForImageAccess(
const spvtools::opt::Instruction& image_access);
/// Returns the given value as an i32. If it's already an i32 then simply returns @p value.
/// Otherwise, wrap the value in a TypeInitializer expression.
/// @param value the value to pass through or convert
/// @returns the value as an i32 value.
TypedExpression ToI32(TypedExpression value);
/// Returns the given value as an u32. If it's already an u32 then simply returns @p value.
/// Otherwise, wrap the value in a TypeInitializer expression.
/// @param value the value to pass through or convert
/// @returns the value as an u32 value.
TypedExpression ToU32(TypedExpression value);
/// Returns the given value as a signed integer type of the same shape if the value is unsigned
/// scalar or vector, by wrapping the value with a TypeInitializer expression. Returns the
/// value itself if the value was already signed.
/// @param value the value to pass through or convert
/// @returns the value itself, or converted to signed integral
TypedExpression ToSignedIfUnsigned(TypedExpression value);
/// @param value_id the value identifier to check
/// @returns true if the given SPIR-V id represents a constant float 0.
bool IsFloatZero(uint32_t value_id);
/// @param value_id the value identifier to check
/// @returns true if the given SPIR-V id represents a constant float 1.
bool IsFloatOne(uint32_t value_id);
private:
/// FunctionDeclaration contains the parsed information for a function header.
struct FunctionDeclaration {
/// Constructor
FunctionDeclaration();
/// Destructor
~FunctionDeclaration();
/// Parsed header source
Source source;
/// Function name
std::string name;
/// Function parameters
ParameterList params;
/// Function return type
const Type* return_type;
/// Function attributes
Attributes attributes;
};
/// Parse the function declaration, which comprises the name, parameters, and
/// return type, populating `decl`.
/// @param decl the FunctionDeclaration to populate
/// @returns true if emission has not yet failed.
bool ParseFunctionDeclaration(FunctionDeclaration* decl);
/// @param obj a SPIR-V instruction with a result ID and a type ID
/// @returns true if the object is an image, a sampler, or a pointer to
/// an image or a sampler
bool IsHandleObj(const spvtools::opt::Instruction& obj);
/// @param obj a SPIR-V instruction with a result ID and a type ID
/// @returns true if the object is an image, a sampler, or a pointer to
/// an image or a sampler
bool IsHandleObj(const spvtools::opt::Instruction* obj);
/// @returns the store type for the OpVariable instruction, or
/// null on failure.
const Type* GetVariableStoreType(const spvtools::opt::Instruction& var_decl_inst);
/// Returns an expression for an instruction operand. Signedness conversion is
/// performed to match the result type of the SPIR-V instruction.
/// @param inst the SPIR-V instruction
/// @param operand_index the index of the operand, counting 0 as the first
/// input operand
/// @returns a new expression node
TypedExpression MakeOperand(const spvtools::opt::Instruction& inst, uint32_t operand_index);
/// Returns an expression for a SPIR-V OpFMod instruction.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeFMod(const spvtools::opt::Instruction& inst);
/// Returns an expression for a SPIR-V OpAccessChain or OpInBoundsAccessChain
/// instruction.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeAccessChain(const spvtools::opt::Instruction& inst);
/// Emits a function call. On failure, emits a diagnostic and returns false.
/// @param inst the SPIR-V function call instruction
/// @returns false if emission failed
bool EmitFunctionCall(const spvtools::opt::Instruction& inst);
/// Emits a control barrier builtin. On failure, emits a diagnostic and
/// returns false.
/// @param inst the SPIR-V control barrier instruction
/// @returns false if emission failed
bool EmitControlBarrier(const spvtools::opt::Instruction& inst);
/// Returns an expression for a SPIR-V instruction that maps to a WGSL
/// builtin function call.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeBuiltinCall(const spvtools::opt::Instruction& inst);
/// Returns an expression for a SPIR-V instruction that maps to the extractBits WGSL
/// builtin function call, with special handling to cast offset and count to u32, if needed.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeExtractBitsCall(const spvtools::opt::Instruction& inst);
/// Returns an expression for a SPIR-V instruction that maps to the insertBits WGSL
/// builtin function call, with special handling to cast offset and count to u32, if needed.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeInsertBitsCall(const spvtools::opt::Instruction& inst);
/// Returns an expression for a SPIR-V OpArrayLength instruction.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeArrayLength(const spvtools::opt::Instruction& inst);
/// Generates an expression for a SPIR-V OpOuterProduct instruction.
/// @param inst the SPIR-V instruction
/// @returns an expression
TypedExpression MakeOuterProduct(const spvtools::opt::Instruction& inst);
/// Generates statements for a SPIR-V OpVectorInsertDynamic instruction.
/// Registers a const declaration for the result.
/// @param inst the SPIR-V instruction
/// @returns an expression
bool MakeVectorInsertDynamic(const spvtools::opt::Instruction& inst);
/// Generates statements for a SPIR-V OpComposite instruction.
/// Registers a const declaration for the result.
/// @param inst the SPIR-V instruction
/// @returns an expression
bool MakeCompositeInsert(const spvtools::opt::Instruction& inst);
/// Get the SPIR-V instruction for the image memory object declaration for
/// the image operand to the given instruction.
/// @param inst the SPIR-V instruction
/// @returns a SPIR-V OpVariable or OpFunctionParameter instruction, or null
/// on error
const spvtools::opt::Instruction* GetImage(const spvtools::opt::Instruction& inst);
/// Get the AST texture the SPIR-V image memory object declaration.
/// @param inst the SPIR-V memory object declaration for the image.
/// @returns a texture type, or null on error
const Texture* GetImageType(const spvtools::opt::Instruction& inst);
/// Get the expression for the image operand from the first operand to the
/// given instruction.
/// @param inst the SPIR-V instruction
/// @returns an identifier expression, or null on error
const ast::Expression* GetImageExpression(const spvtools::opt::Instruction& inst);
/// Get the expression for the sampler operand from the first operand to the
/// given instruction.
/// @param inst the SPIR-V instruction
/// @returns an identifier expression, or null on error
const ast::Expression* GetSamplerExpression(const spvtools::opt::Instruction& inst);
/// Emits a texture builtin function call for a SPIR-V instruction that
/// accesses an image or sampled image.
/// @param inst the SPIR-V instruction
/// @returns true on success, false on error
bool EmitImageAccess(const spvtools::opt::Instruction& inst);
/// Emits statements to implement a SPIR-V image query.
/// @param inst the SPIR-V instruction
/// @returns an expression
bool EmitImageQuery(const spvtools::opt::Instruction& inst);
/// Emits statements to implement a SPIR-V atomic op.
/// @param inst the SPIR-V instruction
/// @returns true on success, false on error
bool EmitAtomicOp(const spvtools::opt::Instruction& inst);
/// Converts the given texel to match the type required for the storage
/// texture with the given type. In WGSL the texel value is always provided
/// as a 4-element vector, but the component type is determined by the
/// texel channel type. See "Texel Formats for Storage Textures" in the WGSL
/// spec. Returns an expression, or emits an error and returns nullptr.
/// @param inst the image access instruction (used for diagnostics)
/// @param texel the texel
/// @param texture_type the type of the storage texture
/// @returns the texel, after necessary conversion.
const ast::Expression* ConvertTexelForStorage(const spvtools::opt::Instruction& inst,
TypedExpression texel,
const Texture* texture_type);
/// Returns an expression for an OpSelect, if its operands are scalars
/// or vectors. These translate directly to WGSL select. Otherwise, return
/// an expression with a null owned expression
/// @param inst the SPIR-V OpSelect instruction
/// @returns a typed expression, or one with a null owned expression
TypedExpression MakeSimpleSelect(const spvtools::opt::Instruction& inst);
/// Finds the header block for a structured construct that we can "break"
/// out from, from deeply nested control flow, if such a block exists.
/// If the construct is:
/// - a switch selection: return the selection header (ending in OpSwitch)
/// - a loop construct: return the loop header block
/// - a continue construct: return the loop header block
/// Otherwise, return nullptr.
/// @param c a structured construct, or nullptr
/// @returns the block info for the structured header we can "break" from,
/// or nullptr
BlockInfo* HeaderIfBreakable(const Construct* c);
/// Appends a new statement to the top of the statement stack.
/// Does nothing if the statement is null.
/// @param statement the new statement
/// @returns a pointer to the statement.
const ast::Statement* AddStatement(const ast::Statement* statement);
/// AddStatementBuilder() constructs and adds the StatementBuilder of type
/// `T` to the top of the statement stack.
/// @param args the arguments forwarded to the T constructor
/// @return the built StatementBuilder
template <typename T, typename... ARGS>
T* AddStatementBuilder(ARGS&&... args) {
TINT_ASSERT(Reader, !statements_stack_.IsEmpty());
return statements_stack_.Back().AddStatementBuilder<T>(std::forward<ARGS>(args)...);
}
/// Returns the source record for the given instruction.
/// @param inst the SPIR-V instruction
/// @return the Source record, or a default one
Source GetSourceForInst(const spvtools::opt::Instruction& inst) const;
/// @returns the last statement in the top of the statement stack.
const ast::Statement* LastStatement();
using CompletionAction = std::function<void(const StatementList&)>;
// A StatementBlock represents a braced-list of statements while it is being
// constructed.
class StatementBlock {
public:
StatementBlock(const Construct* construct,
uint32_t end_id,
CompletionAction completion_action);
StatementBlock(StatementBlock&&);
~StatementBlock();
StatementBlock(const StatementBlock&) = delete;
StatementBlock& operator=(const StatementBlock&) = delete;
/// Replaces any StatementBuilders with the built result, and calls the
/// completion callback (if set). Must only be called once, after all
/// statements have been added with Add().
/// @param builder the program builder
void Finalize(ProgramBuilder* builder);
/// Add() adds `statement` to the block.
/// Add() must not be called after calling Finalize().
void Add(const ast::Statement* statement);
/// AddStatementBuilder() constructs and adds the StatementBuilder of type
/// `T` to the block.
/// Add() must not be called after calling Finalize().
/// @param args the arguments forwarded to the T constructor
/// @return the built StatementBuilder
template <typename T, typename... ARGS>
T* AddStatementBuilder(ARGS&&... args) {
auto builder = std::make_unique<T>(std::forward<ARGS>(args)...);
auto* ptr = builder.get();
Add(ptr);
builders_.emplace_back(std::move(builder));
return ptr;
}
/// @param construct the construct which this construct constributes to
void SetConstruct(const Construct* construct) { construct_ = construct; }
/// @return the construct to which this construct constributes
const Construct* GetConstruct() const { return construct_; }
/// @return the ID of the block at which the completion action should be
/// triggered and this statement block discarded. This is often the `end_id`
/// of `construct` itself.
uint32_t GetEndId() const { return end_id_; }
/// @return the list of statements being built, if this construct is not a
/// switch.
const StatementList& GetStatements() const { return statements_; }
private:
/// The construct to which this construct constributes.
const Construct* construct_;
/// The ID of the block at which the completion action should be triggered
/// and this statement block discarded. This is often the `end_id` of
/// `construct` itself.
const uint32_t end_id_;
/// The completion action finishes processing this statement block.
FunctionEmitter::CompletionAction const completion_action_;
/// The list of statements being built, if this construct is not a switch.
StatementList statements_;
/// Owned statement builders
std::vector<std::unique_ptr<StatementBuilder>> builders_;
/// True if Finalize() has been called.
bool finalized_ = false;
};
/// Pushes an empty statement block onto the statements stack.
/// @param action the completion action for this block
void PushNewStatementBlock(const Construct* construct,
uint32_t end_id,
CompletionAction action);
/// Emits an if-statement whose condition is the given flow guard
/// variable, and pushes onto the statement stack the corresponding
/// statement block ending (and not including) the given block.
/// @param flow_guard name of the flow guard variable
/// @param end_id first block after the if construct.
void PushGuard(const std::string& flow_guard, uint32_t end_id);
/// Emits an if-statement with 'true' condition, and pushes onto the
/// statement stack the corresponding statement block ending (and not
/// including) the given block.
/// @param end_id first block after the if construct.
void PushTrueGuard(uint32_t end_id);
/// @returns a boolean true expression.
const ast::Expression* MakeTrue(const Source&) const;
/// @returns a boolean false expression.
const ast::Expression* MakeFalse(const Source&) const;
/// @param expr the expression to take the address of
/// @returns a TypedExpression that is the address-of `expr` (`&expr`)
/// @note `expr` must be a reference type
TypedExpression AddressOf(TypedExpression expr);
/// Returns AddressOf(expr) if expr is has reference type and
/// the instruction has a pointer result type. Otherwise returns expr.
/// @param expr the expression to take the address of
/// @returns a TypedExpression that is the address-of `expr` (`&expr`)
/// @note `expr` must be a reference type
TypedExpression AddressOfIfNeeded(TypedExpression expr, const spvtools::opt::Instruction* inst);
/// @param expr the expression to dereference
/// @returns a TypedExpression that is the dereference-of `expr` (`*expr`)
/// @note `expr` must be a pointer type
TypedExpression Dereference(TypedExpression expr);
/// Creates a new `ast::Node` owned by the ProgramBuilder.
/// @param args the arguments to pass to the type initializer
/// @returns the node pointer
template <typename T, typename... ARGS>
T* create(ARGS&&... args) const {
return builder_.create<T>(std::forward<ARGS>(args)...);
}
using PtrAs = ParserImpl::PtrAs;
ParserImpl& parser_impl_;
TypeManager& ty_;
ProgramBuilder& builder_;
spvtools::opt::IRContext& ir_context_;
spvtools::opt::analysis::DefUseManager* def_use_mgr_;
spvtools::opt::analysis::ConstantManager* constant_mgr_;
spvtools::opt::analysis::TypeManager* type_mgr_;
FailStream& fail_stream_;
Namer& namer_;
const spvtools::opt::Function& function_;
// The SPIR-V ID for the SampleMask input variable.
uint32_t sample_mask_in_id;
// The SPIR-V ID for the SampleMask output variable.
uint32_t sample_mask_out_id;
// A stack of statement lists. Each list is contained in a construct in
// the next deeper element of stack. The 0th entry represents the statements
// for the entire function. This stack is never empty.
// The `construct` member for the 0th element is only valid during the
// lifetime of the EmitFunctionBodyStatements method.
utils::Vector<StatementBlock, 8> statements_stack_;
// The map of IDs that have already had an identifier name generated for it,
// to their Type.
std::unordered_map<uint32_t, const Type*> identifier_types_;
// Mapping from SPIR-V ID that is used at most once, to its AST expression.
std::unordered_map<uint32_t, TypedExpression> singly_used_values_;
// The IDs of basic blocks, in reverse structured post-order (RSPO).
// This is the output order for the basic blocks.
std::vector<uint32_t> block_order_;
// Mapping from block ID to its bookkeeping info.
std::unordered_map<uint32_t, std::unique_ptr<BlockInfo>> block_info_;
// Mapping from a result ID to its bookkeeping info. This may be
// either a result ID defined in the function body, or the ID of a
// module-scope variable.
std::unordered_map<uint32_t, std::unique_ptr<DefInfo>> def_info_;
// Structured constructs, where enclosing constructs precede their children.
ConstructList constructs_;
// Information about entry point, if this function is referenced by one
const EntryPointInfo* ep_info_ = nullptr;
};
} // namespace tint::reader::spirv
#endif // SRC_TINT_LANG_SPIRV_READER_FUNCTION_H_