Target

struct Target

A struct representing a target machine and os to generate code for.

Public Types

enum OS

The operating system used by the target.

Determines which system calls to generate. Corresponds to os_name_map in Target.cpp.

Values:

enumerator OSUnknown

enumerator Linux

enumerator Windows

enumerator OSX

enumerator Android

enumerator IOS

enumerator QuRT

enumerator NoOS

enumerator Fuchsia

enumerator WebAssemblyRuntime

enum Arch

The architecture used by the target.

Determines the instruction set to use. Corresponds to arch_name_map in Target.cpp.

Values:

enumerator ArchUnknown

enumerator X86

enumerator ARM

enumerator Hexagon

enumerator POWERPC

enumerator WebAssembly

enumerator RISCV

enum Processor

The specific processor to target or tune for.

Mirrors halide_target_processor_t in HalideRuntime.h and corresponds to processor_name_map in Target.cpp.

New entries should be added to the end.

Values:

enumerator ProcessorGeneric

Do not tune for any specific CPU. In practice, this means that halide will decide the tune CPU based on the enabled features.

enumerator K8

enumerator K8_SSE3

enumerator AMDFam10

enumerator BtVer1

enumerator BdVer1

enumerator BdVer2

enumerator BdVer3

enumerator BdVer4

enumerator BtVer2

enumerator ZnVer1

enumerator ZnVer2

enumerator ZnVer3

enumerator ZnVer4

enumerator ZnVer5

enum Feature

Optional features a target can have.

Corresponds to feature_name_map in Target.cpp. See definitions in HalideRuntime.h for full information.

Values:

enumerator JIT

enumerator Debug

enumerator EnableBacktraces

enumerator NoAsserts

enumerator NoBoundsQuery

enumerator SSE41

enumerator AVX

enumerator AVX2

enumerator AVXVNNI

enumerator FMA

enumerator FMA4

enumerator F16C

enumerator ARMv7s

enumerator NoNEON

enumerator VSX

enumerator POWER_ARCH_2_07

enumerator CUDA

enumerator CUDACapability30

enumerator CUDACapability32

enumerator CUDACapability35

enumerator CUDACapability50

enumerator CUDACapability61

enumerator CUDACapability70

enumerator CUDACapability75

enumerator CUDACapability80

enumerator CUDACapability86

enumerator CUDACapability89

enumerator CUDACapability90

enumerator CUDACapability100

enumerator CUDACapability120

enumerator OpenCL

enumerator CLDoubles

enumerator CLHalf

enumerator CLAtomics64

enumerator EGL

enumerator UserContext

enumerator Profile

enumerator NoRuntime

enumerator Metal

enumerator CPlusPlusMangling

enumerator LargeBuffers

enumerator HexagonDma

enumerator HVX_128

enumerator HVX

enumerator HVX_v62

enumerator HVX_v65

enumerator HVX_v66

enumerator HVX_v68

enumerator FuzzFloatStores

enumerator SoftFloatABI

enumerator MSAN

enumerator AVX512

enumerator AVX512_KNL

enumerator AVX512_Skylake

enumerator AVX512_Cannonlake

enumerator AVX512_SapphireRapids

enumerator AVX512_Zen4

enumerator AVX512_Zen5

enumerator TraceLoads

enumerator TraceStores

enumerator TraceRealizations

enumerator TracePipeline

enumerator D3D12Compute

enumerator StrictFloat

enumerator TSAN

enumerator ASAN

enumerator CheckUnsafePromises

enumerator EmbedBitcode

enumerator EnableLLVMLoopOpt

enumerator WasmMvpOnly

enumerator WasmSimd128

enumerator WasmThreads

enumerator WasmBulkMemory

enumerator WebGPU

enumerator SVE

enumerator SVE2

enumerator SME2

enumerator SME_SVL128

enumerator SME_SVL256

enumerator SME_SVL512

enumerator SME_SVL1024

enumerator SME_SVL2048

enumerator ARMDotProd

enumerator ARMFp16

enumerator LLVMLargeCodeModel

enumerator RVV

enumerator ARMv8a

enumerator ARMv81a

enumerator ARMv82a

enumerator ARMv83a

enumerator ARMv84a

enumerator ARMv85a

enumerator ARMv86a

enumerator ARMv87a

enumerator ARMv88a

enumerator ARMv89a

enumerator SanitizerCoverage

enumerator ProfileByTimer

enumerator SPIRV

enumerator Vulkan

enumerator VulkanInt8

enumerator VulkanInt16

enumerator VulkanInt64

enumerator VulkanFloat16

enumerator VulkanFloat64

enumerator VulkanV10

enumerator VulkanV12

enumerator VulkanV13

enumerator Semihosting

enumerator AVX10_1

enumerator X86APX

enumerator Simulator

enumerator HLSL_SM60

enumerator HLSL_SM61

enumerator HLSL_SM62

enumerator HLSL_SM63

enumerator HLSL_SM64

enumerator HLSL_SM65

enumerator HLSL_SM66

enumerator HLSL_SM67

enumerator HLSL_SM68

enumerator HLSL_SM69

enumerator FeatureEnd

Public Functions

explicit Target(const std::string &s)

Given a string of the form used in HL_TARGET (e.g.

“x86-64-avx”), construct the Target it specifies. Note that this always starts with the result of get_host_target(), replacing only the parts found in the target string, so if you omit (say) an OS specification, the host OS will be used instead. An empty string is exactly equivalent to get_host_target().

Invalid target strings will fail with a user_error.

bool has_unknowns() const

Return true if any of the arch/bits/os fields are “unknown”/0; return false otherwise.

void set_implied_features()

Set any feature flags that are implied by the flags currently set.

For example, setting AVX2 implies AVX, so calling this on a target with the AVX2 feature will also set the AVX feature. The set of implications is a DAG, so this reaches a fixed point in a single pass. Call this before inspecting a target’s features, so that (e.g.) a check for SSE41 succeeds on an AVX2 target.

void unset_implied_features()

Unset any feature flags that are implied by other flags that remain set, producing the minimal set of feature flags that set_implied_features() would expand back to the same target.

For example, on a target with both AVX2 and AVX set, this unsets AVX (since AVX2 implies it), but on a target with only AVX set it leaves AVX alone. Call this before emitting a target as a string, to get a compact canonical form.

Target with_implied_features() const

Return a copy of the target with set_implied_features() applied.

Target without_implied_features() const

Return a copy of the target with unset_implied_features() applied.

Target with_feature(Feature f) const

Return a copy of the target with the given feature set.

This is convenient when enabling certain features (e.g. NoBoundsQuery) in an initialization list, where the target to be mutated may be a const reference.

Target without_feature(Feature f) const

Return a copy of the target with the given feature cleared.

This is convenient when disabling certain features (e.g. NoBoundsQuery) in an initialization list, where the target to be mutated may be a const reference.

bool has_gpu_feature() const

Is a fully feature GPU compute runtime enabled?

I.e. is Func::gpu_tile and similar going to work? Currently includes CUDA, OpenCL, Metal and D3D12Compute.

bool supports_type(const Type &t) const

Does this target allow using a certain type.

Generally all types except 64-bit float and int/uint should be supported by all backends.

It is likely better to call the version below which takes a DeviceAPI.

bool supports_type(const Type &t, DeviceAPI device) const

Does this target allow using a certain type on a certain device.

This is the preferred version of this routine.

bool supports_device_api(DeviceAPI api) const

Returns whether a particular device API can be used with this Target.

DeviceAPI get_required_device_api() const

If this Target (including all Features) requires a specific DeviceAPI, return it.

If it doesn’t, return DeviceAPI::None. If the Target has features with multiple (different) DeviceAPI requirements, the result will be an arbitrary DeviceAPI.

bool get_runtime_compatible_target(const Target &other, Target &result)

Create a “greatest common denominator” runtime target that is compatible with both this target and other.

Used by generators to conveniently select a suitable runtime when linking together multiple functions.

Parameters:

• other – The other target from which we compute the gcd target.

• result – [out] The gcd target if we return true, otherwise unmodified. Can be the same as *this.

Returns:

Whether it was possible to find a compatible target (true) or not.

std::string to_string() const

Convert the Target into a string form that can be reconstituted by merge_string(), which will always be of the form.

arch-bits-os-processor-feature1-feature2…featureN.

Note that is guaranteed that Target(t1.to_string()) == t1, but not that Target(s).to_string() == s (since there can be multiple strings that parse to the same Target)… unless t1 contains ‘unknown’ fields (in which case you’ll get a string that can’t be parsed, which is intentional).

int natural_vector_size(const Halide::Type &t) const

Given a data type, return an estimate of the “natural” vector size for that data type when compiling for this Target.

int sme_streaming_vector_bits() const

Return the fixed SME streaming vector length in bits selected by this target, or 0 if no SME_SVL feature is set.

template<typename data_t>
inline int natural_vector_size() const

Given a data type, return an estimate of the “natural” vector size for that data type when compiling for this Target.

inline bool has_large_buffers() const

Return true iff 64 bits and has_feature(LargeBuffers).

inline int64_t maximum_buffer_size() const

Return the maximum buffer size in bytes supported on this Target.

This is 2^31 - 1 except on 64-bit targets when the LargeBuffers feature is enabled, which expands the maximum to 2^63 - 1.

int get_cuda_capability_lower_bound() const

Get the minimum cuda capability found as an integer.

Returns 20 (our minimum supported cuda compute capability) if no cuda features are set.

int get_vulkan_capability_lower_bound() const

Get the minimum Vulkan capability found as an integer.

Returns 10 (our minimum supported Vulkan compute capability) if no Vulkan features are set.

int get_d3d12compute_capability_lower_bound() const

Get the minimum D3D12Compute Shader Model version as an integer (e.g.

60 for SM 6.0, 62 for SM 6.2). Returns 51 (SM 5.1, FXC path) if no SM 6.x features are set, or -1 if D3D12Compute is not enabled.

int get_arm_v8_lower_bound() const

Get the minimum ARM v8.x capability found as an integer.

Returns -1 if no ARM v8.x features are set.

bool supported() const

Was libHalide compiled with support for this target?

inline const std::bitset<FeatureEnd> &get_features_bitset() const

Return a bitset of the Featuress set in this Target (set = 1).

Note that while this happens to be the current internal representation, that might not always be the case.

Public Members

int bits = 0

The bit-width of the target machine.

Must be 0 for unknown, or 32 or 64.

int vector_bits = 0

The bit-width of a vector register for targets where this is configurable and targeting a fixed size is desired.

The default of 0 indicates no assumption of fixed size is allowed.

Public Static Functions

static bool validate_target_string(const std::string &s)

Check if a target string is valid.

static std::string feature_to_name(Target::Feature feature)

Return the name corresponding to a given Feature, in the form used to construct Target strings (e.g., Feature::Debug is “debug” and not “Debug”).

static Target::Feature feature_from_name(const std::string &name)

Return the feature corresponding to a given name, in the form used to construct Target strings (e.g., Feature::Debug is “debug” and not “Debug”).

If the string is not a known feature name, return FeatureEnd.

static Target::Feature sme_svl_feature_from_bits(int bits)

Return the SME_SVL feature corresponding to an SME streaming vector length in bits, or FeatureEnd if no exact SME_SVL feature exists.