glslang

name	glslang
description	glslang SPIR-V Builder API for types, instructions, control flow, and decorations.

glslang SPIR-V Usage

Located in src/ext/glslang/SPIRV. Headers:

#include "SPIRV/SpvBuilder.h"
#include "SPIRV/spvIR.h"
#include "SPIRV/GlslangToSpv.h"
#include "SPIRV/disassemble.h"

Code snippets follow glslang's own conventions (e.g. camelCase builder methods). LuisaCompute project style rules apply to project code, while src/ext/glslang is third-party code.

SpvBuilder Lifecycle

spv::Builder owns one SPIR-V module. Thread-safe internal IR.

spv::SpvBuildLogger logger;
spv::Builder builder(spv::Spv_1_5, 0, &logger);
builder.setSource(spv::SourceLanguage::GLSL, 450);
builder.setMemoryModel(spv::AddressingModel::Logical, spv::MemoryModel::GLSL450);
builder.addCapability(spv::Capability::Shader);
// ... build ...
std::vector<unsigned int> spirv;
builder.dump(spirv);

Module Setup

builder.setSource(spv::SourceLanguage::GLSL, 450);
builder.setEmitSpirvDebugInfo();                    // required before setting debug locations
builder.setDebugMainSourceFile("shader.frag");
builder.setDebugSourceLocation(10, "shader.frag");
builder.addCapability(spv::Capability::Shader);
builder.addExtension("SPV_KHR_ray_tracing");
builder.setMemoryModel(spv::AddressingModel::Logical, spv::MemoryModel::GLSL450);
spv::Id glsl450 = builder.import("GLSL.std.450");

Types (canonicalized)

spv::Id voidTy   = builder.makeVoidType();
spv::Id boolTy   = builder.makeBoolType();
spv::Id int32Ty  = builder.makeIntType(32);
spv::Id uint32Ty = builder.makeUintType(32);
spv::Id uint64Ty = builder.makeUintType(64);
spv::Id floatTy  = builder.makeFloatType(32);
spv::Id doubleTy = builder.makeFloatType(64);
spv::Id halfTy   = builder.makeFloatType(16);
spv::Id bfloat16 = builder.makeBFloat16Type();
spv::Id float8e5 = builder.makeFloatE5M2Type();
spv::Id float8e4 = builder.makeFloatE4M3Type();

spv::Id vec4Ty   = builder.makeVectorType(floatTy, 4);
spv::Id mat4x4Ty = builder.makeMatrixType(floatTy, 4, 4);
spv::Id arrTy    = builder.makeArrayType(floatTy, builder.makeUintConstant(16), 0);
spv::Id runArrTy = builder.makeRuntimeArray(floatTy);

std::vector<spv::Id> members = {floatTy, int32Ty};
// Second argument is member debug info; use {} when no per-member debug data is needed.
spv::Id structTy = builder.makeStructType(members, {}, "MyStruct", false);

spv::Id ptrTy     = builder.makePointer(spv::StorageClass::Function, floatTy);
spv::Id fwdPtrTy  = builder.makeForwardPointer(spv::StorageClass::PhysicalStorageBuffer);
// Resolve a forward pointer to its pointee type once the pointee is known.
spv::Id resolvedPtrTy = builder.makePointerFromForwardPointer(spv::StorageClass::PhysicalStorageBuffer, fwdPtrTy, floatTy);
spv::Id untypedPtr= builder.(spv::StorageClass::StorageBuffer);
spv::Id fnTy      = builder.(voidTy, {floatTy, int32Ty});

spv::Id imgTy       = builder.(floatTy, spv::Dim::Dim2D, , , , , spv::ImageFormat::Rgba32f, );
spv::Id sampledImgTy= builder.(imgTy, );
spv::Id samplerTy   = builder.();

spv::Id asTy = builder.();
spv::Id rqTy = builder.();
spv::Id hoTy = builder.();

spv::Id coopMatTy = builder.(floatTy, scopeId, rowsId, colsId, useId);
spv::Id coopVecTy = builder.(floatTy, componentsId);
spv::Id tensorTy  = builder.(floatTy, rankId);


std::vector<spv::IdImmediate> ops = {{, someId}};
spv::Id genericTy = builder.(spv::Op::OpType..., ops);

Type Queries

spv::Id typeId = builder.getTypeId(resultId);
spv::Op opCode = builder.getOpCode(id);
spv::Op cls    = builder.getTypeClass(typeId);
bool isPtr     = builder.isPointer(id);
bool isScalar  = builder.isScalar(id);
bool isVec     = builder.isVector(id);
bool isMat     = builder.isMatrix(id);
bool isArray   = builder.isArrayType(typeId);
bool isStruct  = builder.isStructType(typeId);
bool isImage   = builder.isImageType(typeId);
bool isSampler = builder.isSamplerType(typeId);
int  width     = builder.getScalarTypeWidth(typeId);
spv::Id scalar = builder.getScalarTypeId(typeId);
spv::Id contained = builder.getContainedTypeId(typeId);     // single
spv::Id contained = builder.getContainedTypeId(typeId, n);  // nth
unsigned cols = builder.getNumColumns(id);
unsigned rows = builder.getNumRows(id);
unsigned comps= builder.getNumComponents(id);

Constants (deduplicated; spec constants not)

spv::Id t = builder.makeBoolConstant(true), f = builder.makeBoolConstant(false);
spv::Id i32 = builder.makeIntConstant(5), u32 = builder.makeUintConstant(7);
spv::Id i64 = builder.makeInt64Constant(9), u64 = builder.makeUint64Constant(11);
spv::Id i8  = builder.makeInt8Constant(1),  u8  = builder.makeUint8Constant(2);
spv::Id i16 = builder.makeInt16Constant(3), u16 = builder.makeUint16Constant(4);
spv::Id f32 = builder.makeFloatConstant(1.0f), f64 = builder.makeDoubleConstant(2.0);
spv::Id f16 = builder.makeFloat16Constant(3.0f), bf16 = builder.makeBFloat16Constant(4.0f);
spv::Id fp  = builder.makeFpConstant(floatTy, 1.5, false);
spv::Id null= builder.makeNullConstant(structTy);

// Composite
spv::Id vec4 = builder.makeCompositeConstant(vec4Ty, {f32, f32, f32, f32});

// Spec constants
spv::Id specI32 = builder.makeIntConstant(builder.makeIntType(32), 10, true);
spv::Id specVec = builder.makeCompositeConstant(vec4Ty, {f32, f32, f32, f32}, true);

Variables

spv::Id global = builder.createVariable(spv::Decoration::NoPrecision, spv::StorageClass::Private, floatTy, "g", builder.makeFloatConstant(0.0f));
spv::Id local  = builder.createVariable(spv::Decoration::NoPrecision, spv::StorageClass::Function, floatTy, "l");
spv::Id untyped= builder.createUntypedVariable(spv::Decoration::NoPrecision, spv::StorageClass::StorageBuffer, "u", dataTypeId, initId);
spv::Id undef  = builder.createUndefined(floatTy);

Functions

// Entry point
spv::Function* entry = builder.makeEntryPoint("main");
builder.addEntryPoint(spv::ExecutionModel::Fragment, entry, "main");
builder.addExecutionMode(entry, spv::ExecutionMode::OriginUpperLeft);

// Regular function
spv::Block* entryBlock = nullptr;
spv::Function* func = builder.makeFunctionEntry(
    spv::Decoration::NoPrecision, floatTy, "myFunc", spv::LinkageType::Max,
    {floatTy, int32Ty},
    {{spv::Decoration::NoPrecision}, {spv::Decoration::NoPrecision}},
    &entryBlock);

builder.enterFunction(func);
builder.setBuildPoint(entryBlock);
spv::Id p0 = func->getParamId(0);
spv::Id p1 = func->getParamId(1);
builder.makeReturn(false, resultId);  // or makeReturn(false) for void
builder.leaveFunction();

Control Flow

If-Then-Else

spv::Builder::If ifBuilder(cond, spv::SelectionControlMask::MaskNone, builder);
// then block
ifBuilder.makeBeginElse();
// else block
ifBuilder.makeEndIf();
// merge block

Switch

std::vector<int> caseValues = {0, 1}, valueToSegment = {0, 1};
int defaultSegment = 2, numSegments = 3;
std::vector<Block*> segmentBB;
builder.makeSwitch(selectorId, spv::SelectionControlMask::MaskNone, numSegments, caseValues, valueToSegment, defaultSegment, segmentBB);
builder.nextSwitchSegment(segmentBB, 0); /* ... */ builder.addSwitchBreak(false);
builder.nextSwitchSegment(segmentBB, 1); /* ... */ builder.addSwitchBreak(false);
builder.nextSwitchSegment(segmentBB, 2); /* ... */ builder.addSwitchBreak(false);
builder.endSwitch(segmentBB);

Loops

spv::Builder::LoopBlocks& loop = builder.makeNewLoop();
builder.setBuildPoint(&loop.head);
builder.createLoopMerge(&loop.merge, &loop.continue_target, spv::LoopControlMask::MaskNone, {});
builder.createConditionalBranch(cond, &loop.body, &loop.merge);
builder.setBuildPoint(&loop.body);
// loop body
builder.createLoopContinue();
builder.setBuildPoint(&loop.continue_target);
// loop increment (optional)
builder.createBranch(false, &loop.head);
builder.setBuildPoint(&loop.merge);
builder.closeLoop();
// break: builder.createLoopExit();  continue: builder.createLoopContinue();

Arithmetic & Logic

spv::Id neg  = builder.createUnaryOp(spv::Op::OpSNegate, int32Ty, val);
spv::Id notb = builder.createUnaryOp(spv::Op::OpLogicalNot, boolTy, bval);
spv::Id add  = builder.createBinOp(spv::Op::OpFAdd, floatTy, a, b);
spv::Id sub  = builder.createBinOp(spv::Op::OpISub, int32Ty, a, b);
spv::Id mul  = builder.createBinOp(spv::Op::OpIMul, int32Ty, a, b);
spv::Id div  = builder.createBinOp(spv::Op::OpFDiv, floatTy, a, b);
spv::Id and_ = builder.createBinOp(spv::Op::OpBitwiseAnd, uint32Ty, a, b);

// ExtInst (ternary)
spv::Id fma = builder.createOp(spv::Op::OpExtInst, floatTy, {glsl450, GLSLstd450Fma, a, b, c});

// Generic n-ary
spv::Id r = builder.createOp(spv::Op::OpVectorTimesMatrix, vec4Ty, {a, b, c});

// Mixed ID/immediates
std::vector<spv::IdImmediate> mixed = {{true, idOp}, {false, (unsigned)spv::MemoryAccessMask::Aligned}};
spv::Id r = builder.createOp(spv::Op::Op..., typeId, mixed);

// SpecConstantOp
spv::Id specAdd = builder.createSpecConstantOp(spv::Op::OpIAdd, int32Ty, {specA, specB}, {});

Memory Instructions

spv::Id loaded = builder.createLoad(ptrId, spv::Decoration::NoPrecision);
builder.createStore(valueId, ptrId);
builder.createStore(valueId, ptrId, spv::MemoryAccessMask::NonUniformPointerEXT, spv::Scope::Device, 4);

// Access chain
std::vector<spv::Id> indexes = {builder.makeUintConstant(0), builder.makeUintConstant(2)};
spv::Id chain = builder.createAccessChain(spv::StorageClass::Function, basePtr, indexes);

// Composite
spv::Id elem  = builder.createCompositeExtract(composite, elemType, 2);
spv::Id elem  = builder.createCompositeExtract(composite, elemType, std::vector<unsigned>{0, 1});
spv::Id ins   = builder.createCompositeInsert(newVal, composite, compositeType, 0);
spv::Id dynEl = builder.createVectorExtractDynamic(vec, elemType, indexId);
spv::Id dynVec= builder.createVectorInsertDynamic(vec, vecType, newElem, indexId);
spv::Id comp  = builder.createCompositeConstruct(vec4Ty, {a, b, c, d});

spv::Id vec4 = builder.createConstructor(spv::Decoration::NoPrecision, {scalarId}, vec4Ty);
spv::Id mat  = builder.createMatrixConstructor(spv::Decoration::NoPrecision, srcs, mat4x4Ty);

// Swizzle
spv::Id swz = builder.createRvalueSwizzle(spv::Decoration::NoPrecision, vec4Ty, vec, {2, 1, 0, 3});
spv::Id lswz= builder.createLvalueSwizzle(vec4Ty, target, source, {2, 1, 0, 3});

// Scalar promotion (in-place)
builder.promoteScalar(spv::Decoration::NoPrecision, left, right);
spv::Id smeared = builder.(spv::Decoration::NoPrecision, scalarId, vec4Ty);

Access Chain Helper

Builder maintains one active access chain for l-value/r-value tracking:

builder.clearAccessChain();
builder.setAccessChainLValue(ptrId);    // base is pointer
builder.setAccessChainRValue(valueId);  // base is r-value
builder.accessChainPush(indexId, coherentFlags, alignment);
builder.accessChainPushSwizzle(channels, preSwizzleBaseType, coherentFlags, alignment);
builder.accessChainPushComponent(componentId, preSwizzleBaseType, coherentFlags, alignment);

spv::Id result = builder.accessChainLoad(precision, lvalNonUniform, rvalNonUniform, resultType, memAccess, scope, n);
builder.accessChainStore(valueId, spv::Decoration::NonUniform,
                         spv::MemoryAccessMask::MaskNone, spv::Scope::Max, 0);
spv::Id lval = builder.accessChainGetLValue();
spv::Id inferred = builder.accessChainGetInferredType();
bool canBeLvalue = builder.isSpvLvalue();  // false for multi-component swizzles like .yx

// Save/restore
spv::Builder::AccessChain saved = builder.getAccessChain();
builder.setAccessChain(saved);

Texture Operations

spv::Builder::TextureParameters params = {};
params.sampler = sampledImageId;
params.coords = coordsId;
params.lod = lodId;  // etc: bias, Dref, offset, gradX, gradY, component, sample, lodClamp, ...
// nonprivate, volatil, nontemporal = false

spv::Id tex = builder.createTextureCall(precision, resultType,
    false/*sparse*/, false/*fetch*/, false/*proj*/, false/*gather*/, false/*noImplicit*/,
    params, spv::ImageOperandsMask::MaskNone);

Decorations & Names

builder.addName(id, "myVar");
builder.addMemberName(structTy, 0, "field0");
builder.addDecoration(id, spv::Decoration::Location, 0);
builder.addDecoration(id, spv::Decoration::Binding, 2);
builder.addDecoration(id, spv::Decoration::DescriptorSet, 0);
builder.addDecoration(id, spv::Decoration::NoContraction);
builder.addDecoration(id, spv::Decoration::RelaxedPrecision);
builder.addDecoration(id, spv::Decoration::BuiltIn, (int)spv::BuiltIn::Position);
builder.addMemberDecoration(structTy, 0, spv::Decoration::Offset, 0);
builder.addMemberDecoration(structTy, 1, spv::Decoration::Offset, 16);
builder.addDecoration(id, spv::Decoration::WorkgroupSize, std::vector<unsigned>{64, 1, 1});
builder.addDecorationId(id, spv::Decoration::ArrayStrideIdEXT, strideId);
builder.addLinkageDecoration(id, "myFunc", spv::LinkageType::Export);

Barriers

builder.createControlBarrier(spv::Scope::Workgroup, spv::Scope::Device,
    spv::MemorySemanticsMask::UniformMemory | spv::MemorySemanticsMask::WorkgroupMemory);
builder.createMemoryBarrier(spv::Scope::Device, spv::MemorySemanticsMask::ImageMemory);

Debug Info

SPIR-V Standard (OpLine/OpSource)

builder.setEmitSpirvDebugInfo();  // enables OpLine/OpSource tracking
builder.setDebugMainSourceFile("shader.glsl");
builder.setDebugSourceLocation(42, "shader.glsl");
builder.setSourceText(sourceText);

NonSemantic Shader Debug Info

builder.setEmitNonSemanticShaderDebugInfo(true);  // also enables OpLine-style tracking
spv::Id debugType = builder.getDebugType(spirvTypeId);
builder.enterLexicalBlock(line, column);
builder.leaveLexicalBlock();
builder.setupFunctionDebugInfo(func, "myFunc", paramTypes, paramNames);
spv::Id dbgGlobal = builder.createDebugGlobalVariable(debugType, "globalVar", varId);
spv::Id dbgLocal  = builder.createDebugLocalVariable(debugType, "localVar", argNumber);
spv::Id dbgDecl   = builder.makeDebugDeclare(dbgLocal, ptrId);
spv::Id dbgVal    = builder.makeDebugValue(dbgLocal, valueId);

Function Calls & Builtins

spv::Id result = builder.createFunctionCall(calleeFunc, {arg0, arg1, arg2});
spv::Id sqrtVal = builder.createBuiltinCall(floatTy, glsl450, GLSLstd450Sqrt, {val});

Post-Processing & Serialization

builder.postProcess(false);       // prune + caps/extensions
builder.postProcessCFG();         // prune unreachable
builder.postProcessFeatures();    // add caps/extensions from instructions
builder.postProcessSamplers();    // move OpSampledImage near users

std::vector<unsigned int> spirv;
builder.dump(spirv);
spv::Disassemble(std::cout, spirv);
glslang::OutputSpvBin(spirv, "out.spv");
glslang::OutputSpvHex(spirv, "out.h", "g_spv");

Both postProcessCFG() and Function::dump() traverse physical blocks with inReadableOrder(), which assumes structured merge roles already nest. If an outer selection merge is also an inner arm and then branches to the inner merge, the physical graph exits the inner construct and re-enters it. The traversal can initially mask that invalid topology by classifying the inner merge as dead, replacing live code with OpUnreachable, and serializing it before its dominator. Fix the producer's physical control-flow plan: preserve the payload blocks but rotate the adjacent merge declarations so the inner merge physically precedes the outer merge. Do not patch serialization order or disable post-processing/validation around an invalid graph.

OpSwitch case literals are sized by the selector's OpTypeInt, not by the generated operand-table class alone. A selector up to 32 bits uses one literal word; a 64-bit selector uses two low-word-first literal words followed by one target label ID. Disassemblers and binary walkers must resolve the selector type and consume ceil(bit_width / 32) words per case before reading the label. Never infer case boundaries by alternating one literal word and one ID.

Treat disassembly input as untrusted. Validate each instruction-local word count before reading operands: reject zero, undersized, or module-truncated instructions. When resolving an OpSwitch selector, also validate the mapped defining instruction bounds and result ID; accept OpTypeInt only with its exact four-word layout and a width of 8, 16, 32, or 64. Validate a directly visited OpTypeInt before reading its width operand. The disassembler's fatal path exits the process, so malformed-input regressions must run it in a child process and assert the deterministic nonzero exit.

IR Classes (spvIR.h)

spv::Instruction* inst = new spv::Instruction(resultId, typeId, spv::Op::OpIAdd);
inst->addIdOperand(opA);
inst->addIdOperand(opB);

spv::Block* block = new spv::Block(blockId, *function);
block->addInstruction(std::unique_ptr<spv::Instruction>(inst));
block->addLocalVariable(std::unique_ptr<spv::Instruction>(varInst));
bool terminated = block->isTerminated();

spv::Function* func = new spv::Function(funcId, retType, funcType, firstParamId, linkage, name, module);
func->addBlock(block);
func->setReturnPrecision(spv::Decoration::RelaxedPrecision);
func->addParamPrecision(0, spv::Decoration::RelaxedPrecision);

spv::Module module;
module.addFunction(func);
module.mapInstruction(inst);
spv::Instruction* found = module.getInstruction(id);
spv::Id typeId = module.getTypeId(resultId);

Key Types

Type	Purpose
spv::Builder	SPIR-V module construction
spv::Instruction	Single SPIR-V instruction
spv::Block	Basic block
spv::Function	SPIR-V function
spv::Module	Module root, ID→instruction map
spv::Builder::If	Structured if-then-else helper
spv::Builder::LoopBlocks	Structured loop blocks
spv::Builder::AccessChain	L-value/R-value access chain
spv::Builder::TextureParameters	Texture op parameters
spv::IdImmediate	Operand: ID or immediate
glslang::SpvOptions	GlslangToSpv options

GlslangToSpv Patterns

From TGlslangToSpvTraverser (src/ext/glslang/SPIRV/GlslangToSpv.cpp). Common pattern: clear access chain → traverse → load/store → set R-value.

visitSymbol

builder.clearAccessChain();
// Treat spec constants, r-value parameters, and non-pointer/untyped values as r-values.
if (isRValue || rValueParameters.count(symbolId) ||
    (!builder.isPointerType(builder.getTypeId(id)) && !builder.isUntypedPointer(id)))
    builder.setAccessChainRValue(id);
else
    builder.setAccessChainLValue(id);

spv::StorageClass sc = builder.getStorageClass(id);
if (builder.isGlobalVariable(id))
    iOSet.insert(id);

builder.addExtension("SPV_GOOGLE_hlsl_functionality1");
builder.addDecorationId(id, spv::Decoration::HlslCounterBufferGOOGLE, counterId);

visitBinary (Assignment)

builder.clearAccessChain(); node->getLeft()->traverse(this);
auto lValue = builder.getAccessChain();
builder.clearAccessChain(); node->getRight()->traverse(this);
spv::Id rValue = accessChainLoad(node->getRight()->getType());
builder.setAccessChain(lValue);
multiTypeStore(node->getLeft()->getType(), rValue);
builder.clearAccessChain(); builder.setAccessChainRValue(rValue);

visitBinary (Array/Vector Index)

// zero-extend narrow uint indexes to 32-bit
if (builder.isUintType(indexType) && builder.getScalarTypeWidth(indexType) < 32)
    index = builder.createUnaryOp(spv::Op::OpUConvert, builder.makeUintType(32), index);
builder.accessChainPush(index, coherentFlags, alignment);

visitBinary (Swizzle)

builder.accessChainPushSwizzle(swizzle, convertGlslangToSpvType(node->getLeft()->getType()),
                               coherentFlags, alignment);

visitUnary (Inc/Dec)

spv::Id operand = builder.accessChainGetLValue();
spv::Id one = builder.makeIntConstant(1);
spv::Id result = builder.createBinOp(op, type, operand, one);
builder.accessChainStore(result, ...);
builder.clearAccessChain(); builder.setAccessChainRValue(result);

visitUnary (Builtin / NoResult / ArrayLength)

// Builtin
spv::Id result = builder.createBuiltinCall(resultType(), glsl450, opcode, {operand});
// No-result
builder.createNoResultOp(spv::Op::OpKill);
builder.createNoResultOp(spv::Op::OpTerminateInvocation);
builder.createNoResultOp(spv::Op::OpDemoteToHelperInvocationEXT);
builder.createNoResultOp(spv::Op::OpAssumeTrueKHR, operand);
// Array length
spv::Id len = builder.createArrayLength(builder.accessChainGetLValue(), member, bits);
len = builder.createUnaryOp(spv::Op::OpBitcast, builder.makeIntType(bits), len);
// Cooperative matrix/vector
spv::Id lenKHR = builder.createCooperativeMatrixLengthKHR(typeId);
spv::Id lenNV  = builder.createCooperativeMatrixLengthNV(typeId);
spv::Id lenVec = builder.getCooperativeVectorNumComponents(typeId);
// Tensor
spv::Id layout = builder.createOp(spv::Op::OpCreateTensorLayoutNV, resultType(), {});
spv::Id view   = builder.createOp(spv::Op::OpCreateTensorViewNV, resultType(), {});

visitAggregate

// Function entry/leave
builder.setBuildPoint(shaderEntry->getLastBlock());
builder.enterFunction(shaderEntry); /* body */ builder.leaveFunction();
// Function call
spv::Id result = builder.createFunctionCall(callee, arguments);
// Constructors
spv::Id c = builder.createConstructor(precision, arguments, resultType());
spv::Id m = builder.createMatrixConstructor(precision, arguments, resultType());
// Builtin
spv::Id r = builder.createBuiltinCall(resultType(), extInst, opcode, arguments);
// Texture
spv::Builder::TextureParameters params = {sampledImageId, coordsId, /*...*/};
spv::Id tex = builder.createTextureCall(precision, resultType(), sparse, fetch, proj, gather, noImplicit, params, mask);
// Sampled image
spv::Id sampled = builder.createOp(spv::Op::OpSampledImage, resultType(), {imageId, samplerId});
// Cooperative matrix conversion
spv::Id coop = builder.createCooperativeMatrixConversion(resultType(), arguments[0]);
// Variable
spv::Id var = builder.createVariable(precision, spv::StorageClass::Function, type, name, init);
// Load/store
spv::Id loaded = builder.createLoad(ptrId, precision);
builder.createStore(valueId, ptrId);
// Debug scopes
builder.enterLexicalBlock(loc.line, loc.column); /* body */ builder.leaveLexicalBlock();

visitSelection

// Scalar ternary
spv::Id result = builder.createTriOp(spv::Op::OpSelect, resultType, cond, trueVal, falseVal);
// Vector selection: for SPIR-V < 1.4 smear the scalar condition to the vector width;
// for SPIR-V >= 1.4 OpSelect accepts a scalar condition directly.
if (builder.getSpvVersion() < spv::Spv_1_4 && builder.isVector(trueVal)) {
    cond = builder.smearScalar(precision, cond,
                               builder.makeVectorType(builder.makeBoolType(),
                                                      builder.getNumComponents(trueVal)));
}
// If aggregate decorations cause type mismatches, normalize with OpCopyLogical.
if (builder.getTypeId(trueVal) != resultType)
    trueVal = builder.createUnaryOp(spv::Op::OpCopyLogical, resultType, trueVal);
if (builder.getTypeId(falseVal) != resultType)
    falseVal = builder.createUnaryOp(spv::Op::OpCopyLogical, resultType, falseVal);
spv::Id result = builder.createTriOp(spv::Op::OpSelect, resultType, cond, trueVal, falseVal);

visitSwitch

std::vector<int> caseValues = {0,1,2}, valueToSegment = {0,1,2};
builder.makeSwitch(selectorId, spv::SelectionControlMask::MaskNone, 4, caseValues, valueToSegment, 3, segmentBB);
builder.nextSwitchSegment(segmentBB, 0); /* case 0 */ builder.addSwitchBreak(false);
// ...
builder.endSwitch(segmentBB);

visitLoop

spv::Builder::LoopBlocks& loop = builder.makeNewLoop();
builder.setBuildPoint(&loop.head);
builder.createLoopMerge(&loop.merge, &loop.continue_target, spv::LoopControlMask::MaskNone, {});
builder.createConditionalBranch(cond, &loop.body, &loop.merge);
builder.setBuildPoint(&loop.body); /* body */ builder.createLoopContinue();
builder.setBuildPoint(&loop.continue_target); /* increment */ builder.createBranch(false, &loop.head);
builder.setBuildPoint(&loop.merge);
builder.closeLoop();

visitBranch

builder.makeReturn(false, returnValue);   // with value
builder.makeReturn(false);                // void
builder.createLoopExit();                 // break
builder.createLoopContinue();             // continue
builder.makeStatementTerminator(spv::Op::OpKill, "post-discard");
builder.makeStatementTerminator(spv::Op::OpTerminateInvocation, "post-terminate");
builder.createNoResultOp(spv::Op::OpDemoteToHelperInvocationEXT);
builder.makeStatementTerminator(spv::Op::OpTerminateRayKHR, "post-terminate-ray");
builder.makeStatementTerminator(spv::Op::OpIgnoreIntersectionKHR, "post-ignore");

visitConstantUnion

spv::Id constantId = createSpvConstant(node);
builder.clearAccessChain();
builder.setAccessChainRValue(constantId);

visitVariableDecl

builder.setDebugSourceLocation(node->getLoc().line, node->getLoc().getFilename());

visitFunctions

// No direct builder usage; drives traversal of the translation unit.