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[Offload] Move (most) global state to an OffloadContext struct #144494

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Merged
merged 3 commits into from
Jun 19, 2025
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[Offload] Move (most) global state to an OffloadContext struct #144494

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475e56c
[Offload] Move (most) global state to an `OffloadContext` struct
RossBrunton Jun 17, 2025
6bac27a
Trace olInit
RossBrunton Jun 17, 2025
932dee4
Added operator=
RossBrunton Jun 19, 2025
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12 changes: 6 additions & 6 deletions offload/liboffload/include/OffloadImpl.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,12 +22,12 @@
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/Error.h"

struct OffloadConfig {
bool TracingEnabled = false;
bool ValidationEnabled = true;
};

OffloadConfig &offloadConfig();
namespace llvm {
namespace offload {
bool isTracingEnabled();
bool isValidationEnabled();
} // namespace offload
} // namespace llvm

// Use the StringSet container to efficiently deduplicate repeated error
// strings (e.g. if the same error is hit constantly in a long running program)
Expand Down
82 changes: 51 additions & 31 deletions offload/liboffload/src/OffloadImpl.cpp
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Expand Up @@ -93,22 +93,36 @@ struct AllocInfo {
ol_alloc_type_t Type;
};

using AllocInfoMapT = DenseMap<void *, AllocInfo>;
AllocInfoMapT &allocInfoMap() {
static AllocInfoMapT AllocInfoMap{};
return AllocInfoMap;
}
// Global shared state for liboffload
struct OffloadContext;
static OffloadContext *OffloadContextVal;
struct OffloadContext {
OffloadContext(OffloadContext &) = delete;
OffloadContext(OffloadContext &&) = delete;
Comment on lines +100 to +101
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You probably want to delete everything except the default constructor..

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I've added "deletes" for operator=, anything else you want me to add?

In the future, olShutDown will need to destruct this object, so I don't think ~OffloadContext could be deleted.

OffloadContext &operator=(OffloadContext &) = delete;
OffloadContext &operator=(OffloadContext &&) = delete;

bool TracingEnabled = false;
bool ValidationEnabled = true;
DenseMap<void *, AllocInfo> AllocInfoMap{};
SmallVector<ol_platform_impl_t, 4> Platforms{};

ol_device_handle_t HostDevice() {
// The host platform is always inserted last
return &Platforms.back().Devices[0];
}

using PlatformVecT = SmallVector<ol_platform_impl_t, 4>;
PlatformVecT &Platforms() {
static PlatformVecT Platforms;
return Platforms;
}
static OffloadContext &get() {
assert(OffloadContextVal);
return *OffloadContextVal;
}
};

ol_device_handle_t HostDevice() {
// The host platform is always inserted last
return &Platforms().back().Devices[0];
// If the context is uninited, then we assume tracing is disabled
bool isTracingEnabled() {
return OffloadContextVal && OffloadContext::get().TracingEnabled;
}
bool isValidationEnabled() { return OffloadContext::get().ValidationEnabled; }

template <typename HandleT> Error olDestroy(HandleT Handle) {
delete Handle;
Expand All @@ -130,18 +144,20 @@ constexpr ol_platform_backend_t pluginNameToBackend(StringRef Name) {
#include "Shared/Targets.def"

void initPlugins() {
auto *Context = new OffloadContext{};

// Attempt to create an instance of each supported plugin.
#define PLUGIN_TARGET(Name) \
do { \
Platforms().emplace_back(ol_platform_impl_t{ \
Context->Platforms.emplace_back(ol_platform_impl_t{ \
std::unique_ptr<GenericPluginTy>(createPlugin_##Name()), \
{}, \
pluginNameToBackend(#Name)}); \
} while (false);
#include "Shared/Targets.def"

// Preemptively initialize all devices in the plugin
for (auto &Platform : Platforms()) {
for (auto &Platform : Context->Platforms) {
// Do not use the host plugin - it isn't supported.
if (Platform.BackendType == OL_PLATFORM_BACKEND_UNKNOWN)
continue;
Expand All @@ -157,15 +173,16 @@ void initPlugins() {
}

// Add the special host device
auto &HostPlatform = Platforms().emplace_back(
auto &HostPlatform = Context->Platforms.emplace_back(
ol_platform_impl_t{nullptr,
{ol_device_impl_t{-1, nullptr, nullptr}},
OL_PLATFORM_BACKEND_HOST});
HostDevice()->Platform = &HostPlatform;
Context->HostDevice()->Platform = &HostPlatform;

Context->TracingEnabled = std::getenv("OFFLOAD_TRACE");
Context->ValidationEnabled = !std::getenv("OFFLOAD_DISABLE_VALIDATION");

offloadConfig().TracingEnabled = std::getenv("OFFLOAD_TRACE");
offloadConfig().ValidationEnabled =
!std::getenv("OFFLOAD_DISABLE_VALIDATION");
OffloadContextVal = Context;
}

// TODO: We can properly reference count here and manage the resources in a more
Expand Down Expand Up @@ -229,7 +246,7 @@ Error olGetDeviceInfoImplDetail(ol_device_handle_t Device,

// Find the info if it exists under any of the given names
auto GetInfo = [&](std::vector<std::string> Names) {
if (Device == HostDevice())
if (Device == OffloadContext::get().HostDevice())
return std::string("Host");

if (!Device->Device)
Expand All @@ -251,8 +268,9 @@ Error olGetDeviceInfoImplDetail(ol_device_handle_t Device,
case OL_DEVICE_INFO_PLATFORM:
return ReturnValue(Device->Platform);
case OL_DEVICE_INFO_TYPE:
return Device == HostDevice() ? ReturnValue(OL_DEVICE_TYPE_HOST)
: ReturnValue(OL_DEVICE_TYPE_GPU);
return Device == OffloadContext::get().HostDevice()
? ReturnValue(OL_DEVICE_TYPE_HOST)
: ReturnValue(OL_DEVICE_TYPE_GPU);
case OL_DEVICE_INFO_NAME:
return ReturnValue(GetInfo({"Device Name"}).c_str());
case OL_DEVICE_INFO_VENDOR:
Expand Down Expand Up @@ -280,7 +298,7 @@ Error olGetDeviceInfoSize_impl(ol_device_handle_t Device,
}

Error olIterateDevices_impl(ol_device_iterate_cb_t Callback, void *UserData) {
for (auto &Platform : Platforms()) {
for (auto &Platform : OffloadContext::get().Platforms) {
for (auto &Device : Platform.Devices) {
if (!Callback(&Device, UserData)) {
break;
Expand Down Expand Up @@ -311,24 +329,25 @@ Error olMemAlloc_impl(ol_device_handle_t Device, ol_alloc_type_t Type,
return Alloc.takeError();

*AllocationOut = *Alloc;
allocInfoMap().insert_or_assign(*Alloc, AllocInfo{Device, Type});
OffloadContext::get().AllocInfoMap.insert_or_assign(*Alloc,
AllocInfo{Device, Type});
return Error::success();
}

Error olMemFree_impl(void *Address) {
if (!allocInfoMap().contains(Address))
if (!OffloadContext::get().AllocInfoMap.contains(Address))
return createOffloadError(ErrorCode::INVALID_ARGUMENT,
"address is not a known allocation");

auto AllocInfo = allocInfoMap().at(Address);
auto AllocInfo = OffloadContext::get().AllocInfoMap.at(Address);
auto Device = AllocInfo.Device;
auto Type = AllocInfo.Type;

if (auto Res =
Device->Device->dataDelete(Address, convertOlToPluginAllocTy(Type)))
return Res;

allocInfoMap().erase(Address);
OffloadContext::get().AllocInfoMap.erase(Address);

return Error::success();
}
Expand Down Expand Up @@ -395,7 +414,8 @@ Error olMemcpy_impl(ol_queue_handle_t Queue, void *DstPtr,
ol_device_handle_t DstDevice, const void *SrcPtr,
ol_device_handle_t SrcDevice, size_t Size,
ol_event_handle_t *EventOut) {
if (DstDevice == HostDevice() && SrcDevice == HostDevice()) {
auto Host = OffloadContext::get().HostDevice();
if (DstDevice == Host && SrcDevice == Host) {
if (!Queue) {
std::memcpy(DstPtr, SrcPtr, Size);
return Error::success();
Expand All @@ -410,11 +430,11 @@ Error olMemcpy_impl(ol_queue_handle_t Queue, void *DstPtr,
// If no queue is given the memcpy will be synchronous
auto QueueImpl = Queue ? Queue->AsyncInfo : nullptr;

if (DstDevice == HostDevice()) {
if (DstDevice == Host) {
if (auto Res =
SrcDevice->Device->dataRetrieve(DstPtr, SrcPtr, Size, QueueImpl))
return Res;
} else if (SrcDevice == HostDevice()) {
} else if (SrcDevice == Host) {
if (auto Res =
DstDevice->Device->dataSubmit(DstPtr, SrcPtr, Size, QueueImpl))
return Res;
Expand Down
5 changes: 0 additions & 5 deletions offload/liboffload/src/OffloadLib.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -30,11 +30,6 @@ ol_code_location_t *&currentCodeLocation() {
return CodeLoc;
}

OffloadConfig &offloadConfig() {
static OffloadConfig Config{};
return Config;
}

namespace llvm {
namespace offload {
// Pull in the declarations for the implementation functions. The actual entry
Expand Down
37 changes: 23 additions & 14 deletions offload/tools/offload-tblgen/EntryPointGen.cpp
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Expand Up @@ -35,21 +35,30 @@ static void EmitValidationFunc(const FunctionRec &F, raw_ostream &OS) {
}
OS << ") {\n";

OS << TAB_1 "if (offloadConfig().ValidationEnabled) {\n";
// Emit validation checks
for (const auto &Return : F.getReturns()) {
for (auto &Condition : Return.getConditions()) {
if (Condition.starts_with("`") && Condition.ends_with("`")) {
auto ConditionString = Condition.substr(1, Condition.size() - 2);
OS << formatv(TAB_2 "if ({0}) {{\n", ConditionString);
OS << formatv(TAB_3 "return createOffloadError(error::ErrorCode::{0}, "
"\"validation failure: {1}\");\n",
Return.getUnprefixedValue(), ConditionString);
OS << TAB_2 "}\n\n";
bool HasValidation = llvm::any_of(F.getReturns(), [](auto &R) {
return llvm::any_of(R.getConditions(), [](auto &C) {
return C.starts_with("`") && C.ends_with("`");
});
});

if (HasValidation) {
OS << TAB_1 "if (llvm::offload::isValidationEnabled()) {\n";
// Emit validation checks
for (const auto &Return : F.getReturns()) {
for (auto &Condition : Return.getConditions()) {
if (Condition.starts_with("`") && Condition.ends_with("`")) {
auto ConditionString = Condition.substr(1, Condition.size() - 2);
OS << formatv(TAB_2 "if ({0}) {{\n", ConditionString);
OS << formatv(TAB_3
"return createOffloadError(error::ErrorCode::{0}, "
"\"validation failure: {1}\");\n",
Return.getUnprefixedValue(), ConditionString);
OS << TAB_2 "}\n\n";
}
}
}
OS << TAB_1 "}\n\n";
}
OS << TAB_1 "}\n\n";

// Perform actual function call to the implementation
ParamNameList = ParamNameList.substr(0, ParamNameList.size() - 2);
Expand All @@ -74,7 +83,7 @@ static void EmitEntryPointFunc(const FunctionRec &F, raw_ostream &OS) {
OS << ") {\n";

// Emit pre-call prints
OS << TAB_1 "if (offloadConfig().TracingEnabled) {\n";
OS << TAB_1 "if (llvm::offload::isTracingEnabled()) {\n";
OS << formatv(TAB_2 "llvm::errs() << \"---> {0}\";\n", F.getName());
OS << TAB_1 "}\n\n";

Expand All @@ -85,7 +94,7 @@ static void EmitEntryPointFunc(const FunctionRec &F, raw_ostream &OS) {
PrefixLower, F.getName(), ParamNameList);

// Emit post-call prints
OS << TAB_1 "if (offloadConfig().TracingEnabled) {\n";
OS << TAB_1 "if (llvm::offload::isTracingEnabled()) {\n";
if (F.getParams().size() > 0) {
OS << formatv(TAB_2 "{0} Params = {{", F.getParamStructName());
for (const auto &Param : F.getParams()) {
Expand Down
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