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llvm-project/clang/lib/Sema/SemaCUDA.cpp

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//===--- SemaCUDA.cpp - Semantic Analysis for CUDA constructs -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements semantic analysis for CUDA constructs.
///
//===----------------------------------------------------------------------===//
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/ExprCXX.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Sema.h"
#include "clang/Sema/SemaDiagnostic.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallVector.h"
using namespace clang;
void Sema::PushForceCUDAHostDevice() {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
ForceCUDAHostDeviceDepth++;
}
bool Sema::PopForceCUDAHostDevice() {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
if (ForceCUDAHostDeviceDepth == 0)
return false;
ForceCUDAHostDeviceDepth--;
return true;
}
ExprResult Sema::ActOnCUDAExecConfigExpr(Scope *S, SourceLocation LLLLoc,
MultiExprArg ExecConfig,
SourceLocation GGGLoc) {
FunctionDecl *ConfigDecl = Context.getcudaConfigureCallDecl();
if (!ConfigDecl)
return ExprError(
Diag(LLLLoc, diag::err_undeclared_var_use)
<< (getLangOpts().HIP ? "hipConfigureCall" : "cudaConfigureCall"));
QualType ConfigQTy = ConfigDecl->getType();
DeclRefExpr *ConfigDR = new (Context)
DeclRefExpr(ConfigDecl, false, ConfigQTy, VK_LValue, LLLLoc);
MarkFunctionReferenced(LLLLoc, ConfigDecl);
return ActOnCallExpr(S, ConfigDR, LLLLoc, ExecConfig, GGGLoc, nullptr,
/*IsExecConfig=*/true);
}
Sema::CUDAFunctionTarget
Sema::IdentifyCUDATarget(const ParsedAttributesView &Attrs) {
bool HasHostAttr = false;
bool HasDeviceAttr = false;
bool HasGlobalAttr = false;
bool HasInvalidTargetAttr = false;
for (const ParsedAttr &AL : Attrs) {
switch (AL.getKind()) {
case ParsedAttr::AT_CUDAGlobal:
HasGlobalAttr = true;
break;
case ParsedAttr::AT_CUDAHost:
HasHostAttr = true;
break;
case ParsedAttr::AT_CUDADevice:
HasDeviceAttr = true;
break;
case ParsedAttr::AT_CUDAInvalidTarget:
HasInvalidTargetAttr = true;
break;
default:
break;
}
}
if (HasInvalidTargetAttr)
return CFT_InvalidTarget;
if (HasGlobalAttr)
return CFT_Global;
if (HasHostAttr && HasDeviceAttr)
return CFT_HostDevice;
if (HasDeviceAttr)
return CFT_Device;
return CFT_Host;
}
template <typename A>
static bool hasAttr(const FunctionDecl *D, bool IgnoreImplicitAttr) {
return D->hasAttrs() && llvm::any_of(D->getAttrs(), [&](Attr *Attribute) {
return isa<A>(Attribute) &&
!(IgnoreImplicitAttr && Attribute->isImplicit());
});
}
/// IdentifyCUDATarget - Determine the CUDA compilation target for this function
Sema::CUDAFunctionTarget Sema::IdentifyCUDATarget(const FunctionDecl *D,
bool IgnoreImplicitHDAttr) {
// Code that lives outside a function is run on the host.
if (D == nullptr)
return CFT_Host;
if (D->hasAttr<CUDAInvalidTargetAttr>())
return CFT_InvalidTarget;
if (D->hasAttr<CUDAGlobalAttr>())
return CFT_Global;
if (hasAttr<CUDADeviceAttr>(D, IgnoreImplicitHDAttr)) {
if (hasAttr<CUDAHostAttr>(D, IgnoreImplicitHDAttr))
return CFT_HostDevice;
return CFT_Device;
} else if (hasAttr<CUDAHostAttr>(D, IgnoreImplicitHDAttr)) {
return CFT_Host;
} else if (D->isImplicit() && !IgnoreImplicitHDAttr) {
// Some implicit declarations (like intrinsic functions) are not marked.
// Set the most lenient target on them for maximal flexibility.
return CFT_HostDevice;
}
return CFT_Host;
}
// * CUDA Call preference table
//
// F - from,
// T - to
// Ph - preference in host mode
// Pd - preference in device mode
// H - handled in (x)
// Preferences: N:native, SS:same side, HD:host-device, WS:wrong side, --:never.
//
// | F | T | Ph | Pd | H |
// |----+----+-----+-----+-----+
// | d | d | N | N | (c) |
// | d | g | -- | -- | (a) |
// | d | h | -- | -- | (e) |
// | d | hd | HD | HD | (b) |
// | g | d | N | N | (c) |
// | g | g | -- | -- | (a) |
// | g | h | -- | -- | (e) |
// | g | hd | HD | HD | (b) |
// | h | d | -- | -- | (e) |
// | h | g | N | N | (c) |
// | h | h | N | N | (c) |
// | h | hd | HD | HD | (b) |
// | hd | d | WS | SS | (d) |
// | hd | g | SS | -- |(d/a)|
// | hd | h | SS | WS | (d) |
// | hd | hd | HD | HD | (b) |
Sema::CUDAFunctionPreference
Sema::IdentifyCUDAPreference(const FunctionDecl *Caller,
const FunctionDecl *Callee) {
assert(Callee && "Callee must be valid.");
CUDAFunctionTarget CallerTarget = IdentifyCUDATarget(Caller);
CUDAFunctionTarget CalleeTarget = IdentifyCUDATarget(Callee);
// If one of the targets is invalid, the check always fails, no matter what
// the other target is.
if (CallerTarget == CFT_InvalidTarget || CalleeTarget == CFT_InvalidTarget)
return CFP_Never;
// (a) Can't call global from some contexts until we support CUDA's
// dynamic parallelism.
if (CalleeTarget == CFT_Global &&
(CallerTarget == CFT_Global || CallerTarget == CFT_Device))
return CFP_Never;
// (b) Calling HostDevice is OK for everyone.
if (CalleeTarget == CFT_HostDevice)
return CFP_HostDevice;
// (c) Best case scenarios
if (CalleeTarget == CallerTarget ||
(CallerTarget == CFT_Host && CalleeTarget == CFT_Global) ||
(CallerTarget == CFT_Global && CalleeTarget == CFT_Device))
return CFP_Native;
// (d) HostDevice behavior depends on compilation mode.
if (CallerTarget == CFT_HostDevice) {
// It's OK to call a compilation-mode matching function from an HD one.
if ((getLangOpts().CUDAIsDevice && CalleeTarget == CFT_Device) ||
(!getLangOpts().CUDAIsDevice &&
(CalleeTarget == CFT_Host || CalleeTarget == CFT_Global)))
return CFP_SameSide;
// Calls from HD to non-mode-matching functions (i.e., to host functions
// when compiling in device mode or to device functions when compiling in
// host mode) are allowed at the sema level, but eventually rejected if
// they're ever codegened. TODO: Reject said calls earlier.
return CFP_WrongSide;
}
// (e) Calling across device/host boundary is not something you should do.
if ((CallerTarget == CFT_Host && CalleeTarget == CFT_Device) ||
(CallerTarget == CFT_Device && CalleeTarget == CFT_Host) ||
(CallerTarget == CFT_Global && CalleeTarget == CFT_Host))
return CFP_Never;
llvm_unreachable("All cases should've been handled by now.");
}
void Sema::EraseUnwantedCUDAMatches(
const FunctionDecl *Caller,
SmallVectorImpl<std::pair<DeclAccessPair, FunctionDecl *>> &Matches) {
if (Matches.size() <= 1)
return;
using Pair = std::pair<DeclAccessPair, FunctionDecl*>;
// Gets the CUDA function preference for a call from Caller to Match.
auto GetCFP = [&](const Pair &Match) {
return IdentifyCUDAPreference(Caller, Match.second);
};
// Find the best call preference among the functions in Matches.
CUDAFunctionPreference BestCFP = GetCFP(*std::max_element(
Matches.begin(), Matches.end(),
[&](const Pair &M1, const Pair &M2) { return GetCFP(M1) < GetCFP(M2); }));
// Erase all functions with lower priority.
llvm::erase_if(Matches,
[&](const Pair &Match) { return GetCFP(Match) < BestCFP; });
}
/// When an implicitly-declared special member has to invoke more than one
/// base/field special member, conflicts may occur in the targets of these
/// members. For example, if one base's member __host__ and another's is
/// __device__, it's a conflict.
/// This function figures out if the given targets \param Target1 and
/// \param Target2 conflict, and if they do not it fills in
/// \param ResolvedTarget with a target that resolves for both calls.
/// \return true if there's a conflict, false otherwise.
static bool
resolveCalleeCUDATargetConflict(Sema::CUDAFunctionTarget Target1,
Sema::CUDAFunctionTarget Target2,
Sema::CUDAFunctionTarget *ResolvedTarget) {
// Only free functions and static member functions may be global.
assert(Target1 != Sema::CFT_Global);
assert(Target2 != Sema::CFT_Global);
if (Target1 == Sema::CFT_HostDevice) {
*ResolvedTarget = Target2;
} else if (Target2 == Sema::CFT_HostDevice) {
*ResolvedTarget = Target1;
} else if (Target1 != Target2) {
return true;
} else {
*ResolvedTarget = Target1;
}
return false;
}
bool Sema::inferCUDATargetForImplicitSpecialMember(CXXRecordDecl *ClassDecl,
CXXSpecialMember CSM,
CXXMethodDecl *MemberDecl,
bool ConstRHS,
bool Diagnose) {
llvm::Optional<CUDAFunctionTarget> InferredTarget;
// We're going to invoke special member lookup; mark that these special
// members are called from this one, and not from its caller.
ContextRAII MethodContext(*this, MemberDecl);
// Look for special members in base classes that should be invoked from here.
// Infer the target of this member base on the ones it should call.
// Skip direct and indirect virtual bases for abstract classes.
llvm::SmallVector<const CXXBaseSpecifier *, 16> Bases;
for (const auto &B : ClassDecl->bases()) {
if (!B.isVirtual()) {
Bases.push_back(&B);
}
}
if (!ClassDecl->isAbstract()) {
for (const auto &VB : ClassDecl->vbases()) {
Bases.push_back(&VB);
}
}
for (const auto *B : Bases) {
const RecordType *BaseType = B->getType()->getAs<RecordType>();
if (!BaseType) {
continue;
}
CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseType->getDecl());
Sema::SpecialMemberOverloadResult SMOR =
LookupSpecialMember(BaseClassDecl, CSM,
/* ConstArg */ ConstRHS,
/* VolatileArg */ false,
/* RValueThis */ false,
/* ConstThis */ false,
/* VolatileThis */ false);
if (!SMOR.getMethod())
continue;
CUDAFunctionTarget BaseMethodTarget = IdentifyCUDATarget(SMOR.getMethod());
if (!InferredTarget.hasValue()) {
InferredTarget = BaseMethodTarget;
} else {
bool ResolutionError = resolveCalleeCUDATargetConflict(
InferredTarget.getValue(), BaseMethodTarget,
InferredTarget.getPointer());
if (ResolutionError) {
if (Diagnose) {
Diag(ClassDecl->getLocation(),
diag::note_implicit_member_target_infer_collision)
<< (unsigned)CSM << InferredTarget.getValue() << BaseMethodTarget;
}
MemberDecl->addAttr(CUDAInvalidTargetAttr::CreateImplicit(Context));
return true;
}
}
}
// Same as for bases, but now for special members of fields.
for (const auto *F : ClassDecl->fields()) {
if (F->isInvalidDecl()) {
continue;
}
const RecordType *FieldType =
Context.getBaseElementType(F->getType())->getAs<RecordType>();
if (!FieldType) {
continue;
}
CXXRecordDecl *FieldRecDecl = cast<CXXRecordDecl>(FieldType->getDecl());
Sema::SpecialMemberOverloadResult SMOR =
LookupSpecialMember(FieldRecDecl, CSM,
/* ConstArg */ ConstRHS && !F->isMutable(),
/* VolatileArg */ false,
/* RValueThis */ false,
/* ConstThis */ false,
/* VolatileThis */ false);
if (!SMOR.getMethod())
continue;
CUDAFunctionTarget FieldMethodTarget =
IdentifyCUDATarget(SMOR.getMethod());
if (!InferredTarget.hasValue()) {
InferredTarget = FieldMethodTarget;
} else {
bool ResolutionError = resolveCalleeCUDATargetConflict(
InferredTarget.getValue(), FieldMethodTarget,
InferredTarget.getPointer());
if (ResolutionError) {
if (Diagnose) {
Diag(ClassDecl->getLocation(),
diag::note_implicit_member_target_infer_collision)
<< (unsigned)CSM << InferredTarget.getValue()
<< FieldMethodTarget;
}
MemberDecl->addAttr(CUDAInvalidTargetAttr::CreateImplicit(Context));
return true;
}
}
}
if (InferredTarget.hasValue()) {
if (InferredTarget.getValue() == CFT_Device) {
MemberDecl->addAttr(CUDADeviceAttr::CreateImplicit(Context));
} else if (InferredTarget.getValue() == CFT_Host) {
MemberDecl->addAttr(CUDAHostAttr::CreateImplicit(Context));
} else {
MemberDecl->addAttr(CUDADeviceAttr::CreateImplicit(Context));
MemberDecl->addAttr(CUDAHostAttr::CreateImplicit(Context));
}
} else {
// If no target was inferred, mark this member as __host__ __device__;
// it's the least restrictive option that can be invoked from any target.
MemberDecl->addAttr(CUDADeviceAttr::CreateImplicit(Context));
MemberDecl->addAttr(CUDAHostAttr::CreateImplicit(Context));
}
return false;
}
bool Sema::isEmptyCudaConstructor(SourceLocation Loc, CXXConstructorDecl *CD) {
if (!CD->isDefined() && CD->isTemplateInstantiation())
InstantiateFunctionDefinition(Loc, CD->getFirstDecl());
// (E.2.3.1, CUDA 7.5) A constructor for a class type is considered
// empty at a point in the translation unit, if it is either a
// trivial constructor
if (CD->isTrivial())
return true;
// ... or it satisfies all of the following conditions:
// The constructor function has been defined.
// The constructor function has no parameters,
// and the function body is an empty compound statement.
if (!(CD->hasTrivialBody() && CD->getNumParams() == 0))
return false;
// Its class has no virtual functions and no virtual base classes.
if (CD->getParent()->isDynamicClass())
return false;
// The only form of initializer allowed is an empty constructor.
// This will recursively check all base classes and member initializers
if (!llvm::all_of(CD->inits(), [&](const CXXCtorInitializer *CI) {
if (const CXXConstructExpr *CE =
dyn_cast<CXXConstructExpr>(CI->getInit()))
return isEmptyCudaConstructor(Loc, CE->getConstructor());
return false;
}))
return false;
return true;
}
bool Sema::isEmptyCudaDestructor(SourceLocation Loc, CXXDestructorDecl *DD) {
// No destructor -> no problem.
if (!DD)
return true;
if (!DD->isDefined() && DD->isTemplateInstantiation())
InstantiateFunctionDefinition(Loc, DD->getFirstDecl());
// (E.2.3.1, CUDA 7.5) A destructor for a class type is considered
// empty at a point in the translation unit, if it is either a
// trivial constructor
if (DD->isTrivial())
return true;
// ... or it satisfies all of the following conditions:
// The destructor function has been defined.
// and the function body is an empty compound statement.
if (!DD->hasTrivialBody())
return false;
const CXXRecordDecl *ClassDecl = DD->getParent();
// Its class has no virtual functions and no virtual base classes.
if (ClassDecl->isDynamicClass())
return false;
// Only empty destructors are allowed. This will recursively check
// destructors for all base classes...
if (!llvm::all_of(ClassDecl->bases(), [&](const CXXBaseSpecifier &BS) {
if (CXXRecordDecl *RD = BS.getType()->getAsCXXRecordDecl())
return isEmptyCudaDestructor(Loc, RD->getDestructor());
return true;
}))
return false;
// ... and member fields.
if (!llvm::all_of(ClassDecl->fields(), [&](const FieldDecl *Field) {
if (CXXRecordDecl *RD = Field->getType()
->getBaseElementTypeUnsafe()
->getAsCXXRecordDecl())
return isEmptyCudaDestructor(Loc, RD->getDestructor());
return true;
}))
return false;
return true;
}
void Sema::checkAllowedCUDAInitializer(VarDecl *VD) {
if (VD->isInvalidDecl() || !VD->hasInit() || !VD->hasGlobalStorage())
return;
const Expr *Init = VD->getInit();
if (VD->hasAttr<CUDADeviceAttr>() || VD->hasAttr<CUDAConstantAttr>() ||
VD->hasAttr<CUDASharedAttr>()) {
assert(!VD->isStaticLocal() || VD->hasAttr<CUDASharedAttr>());
bool AllowedInit = false;
if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Init))
AllowedInit =
isEmptyCudaConstructor(VD->getLocation(), CE->getConstructor());
// We'll allow constant initializers even if it's a non-empty
// constructor according to CUDA rules. This deviates from NVCC,
// but allows us to handle things like constexpr constructors.
if (!AllowedInit &&
(VD->hasAttr<CUDADeviceAttr>() || VD->hasAttr<CUDAConstantAttr>()))
AllowedInit = VD->getInit()->isConstantInitializer(
Context, VD->getType()->isReferenceType());
// Also make sure that destructor, if there is one, is empty.
if (AllowedInit)
if (CXXRecordDecl *RD = VD->getType()->getAsCXXRecordDecl())
AllowedInit =
isEmptyCudaDestructor(VD->getLocation(), RD->getDestructor());
if (!AllowedInit) {
Diag(VD->getLocation(), VD->hasAttr<CUDASharedAttr>()
? diag::err_shared_var_init
: diag::err_dynamic_var_init)
<< Init->getSourceRange();
VD->setInvalidDecl();
}
} else {
// This is a host-side global variable. Check that the initializer is
// callable from the host side.
const FunctionDecl *InitFn = nullptr;
if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Init)) {
InitFn = CE->getConstructor();
} else if (const CallExpr *CE = dyn_cast<CallExpr>(Init)) {
InitFn = CE->getDirectCallee();
}
if (InitFn) {
CUDAFunctionTarget InitFnTarget = IdentifyCUDATarget(InitFn);
if (InitFnTarget != CFT_Host && InitFnTarget != CFT_HostDevice) {
Diag(VD->getLocation(), diag::err_ref_bad_target_global_initializer)
<< InitFnTarget << InitFn;
Diag(InitFn->getLocation(), diag::note_previous_decl) << InitFn;
VD->setInvalidDecl();
}
}
}
}
// With -fcuda-host-device-constexpr, an unattributed constexpr function is
// treated as implicitly __host__ __device__, unless:
// * it is a variadic function (device-side variadic functions are not
// allowed), or
// * a __device__ function with this signature was already declared, in which
// case in which case we output an error, unless the __device__ decl is in a
// system header, in which case we leave the constexpr function unattributed.
//
// In addition, all function decls are treated as __host__ __device__ when
// ForceCUDAHostDeviceDepth > 0 (corresponding to code within a
// #pragma clang force_cuda_host_device_begin/end
// pair).
void Sema::maybeAddCUDAHostDeviceAttrs(FunctionDecl *NewD,
const LookupResult &Previous) {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
if (ForceCUDAHostDeviceDepth > 0) {
if (!NewD->hasAttr<CUDAHostAttr>())
NewD->addAttr(CUDAHostAttr::CreateImplicit(Context));
if (!NewD->hasAttr<CUDADeviceAttr>())
NewD->addAttr(CUDADeviceAttr::CreateImplicit(Context));
return;
}
if (!getLangOpts().CUDAHostDeviceConstexpr || !NewD->isConstexpr() ||
NewD->isVariadic() || NewD->hasAttr<CUDAHostAttr>() ||
NewD->hasAttr<CUDADeviceAttr>() || NewD->hasAttr<CUDAGlobalAttr>())
return;
// Is D a __device__ function with the same signature as NewD, ignoring CUDA
// attributes?
auto IsMatchingDeviceFn = [&](NamedDecl *D) {
if (UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(D))
D = Using->getTargetDecl();
FunctionDecl *OldD = D->getAsFunction();
return OldD && OldD->hasAttr<CUDADeviceAttr>() &&
!OldD->hasAttr<CUDAHostAttr>() &&
!IsOverload(NewD, OldD, /* UseMemberUsingDeclRules = */ false,
/* ConsiderCudaAttrs = */ false);
};
auto It = llvm::find_if(Previous, IsMatchingDeviceFn);
if (It != Previous.end()) {
// We found a __device__ function with the same name and signature as NewD
// (ignoring CUDA attrs). This is an error unless that function is defined
// in a system header, in which case we simply return without making NewD
// host+device.
NamedDecl *Match = *It;
if (!getSourceManager().isInSystemHeader(Match->getLocation())) {
Diag(NewD->getLocation(),
diag::err_cuda_unattributed_constexpr_cannot_overload_device)
<< NewD;
Diag(Match->getLocation(),
diag::note_cuda_conflicting_device_function_declared_here);
}
return;
}
NewD->addAttr(CUDAHostAttr::CreateImplicit(Context));
NewD->addAttr(CUDADeviceAttr::CreateImplicit(Context));
}
// In CUDA, there are some constructs which may appear in semantically-valid
// code, but trigger errors if we ever generate code for the function in which
// they appear. Essentially every construct you're not allowed to use on the
// device falls into this category, because you are allowed to use these
// constructs in a __host__ __device__ function, but only if that function is
// never codegen'ed on the device.
//
// To handle semantic checking for these constructs, we keep track of the set of
// functions we know will be emitted, either because we could tell a priori that
// they would be emitted, or because they were transitively called by a
// known-emitted function.
//
// We also keep a partial call graph of which not-known-emitted functions call
// which other not-known-emitted functions.
//
// When we see something which is illegal if the current function is emitted
// (usually by way of CUDADiagIfDeviceCode, CUDADiagIfHostCode, or
// CheckCUDACall), we first check if the current function is known-emitted. If
// so, we immediately output the diagnostic.
//
// Otherwise, we "defer" the diagnostic. It sits in Sema::CUDADeferredDiags
// until we discover that the function is known-emitted, at which point we take
// it out of this map and emit the diagnostic.
Sema::CUDADiagBuilder::CUDADiagBuilder(Kind K, SourceLocation Loc,
unsigned DiagID, FunctionDecl *Fn,
Sema &S)
: S(S), Loc(Loc), DiagID(DiagID), Fn(Fn),
ShowCallStack(K == K_ImmediateWithCallStack || K == K_Deferred) {
switch (K) {
case K_Nop:
break;
case K_Immediate:
case K_ImmediateWithCallStack:
ImmediateDiag.emplace(S.Diag(Loc, DiagID));
break;
case K_Deferred:
assert(Fn && "Must have a function to attach the deferred diag to.");
PartialDiag.emplace(S.PDiag(DiagID));
break;
}
}
// Print notes showing how we can reach FD starting from an a priori
// known-callable function.
static void EmitCallStackNotes(Sema &S, FunctionDecl *FD) {
auto FnIt = S.CUDAKnownEmittedFns.find(FD);
while (FnIt != S.CUDAKnownEmittedFns.end()) {
DiagnosticBuilder Builder(
S.Diags.Report(FnIt->second.Loc, diag::note_called_by));
Builder << FnIt->second.FD;
Builder.setForceEmit();
FnIt = S.CUDAKnownEmittedFns.find(FnIt->second.FD);
}
}
Sema::CUDADiagBuilder::~CUDADiagBuilder() {
if (ImmediateDiag) {
// Emit our diagnostic and, if it was a warning or error, output a callstack
// if Fn isn't a priori known-emitted.
bool IsWarningOrError = S.getDiagnostics().getDiagnosticLevel(
DiagID, Loc) >= DiagnosticsEngine::Warning;
ImmediateDiag.reset(); // Emit the immediate diag.
if (IsWarningOrError && ShowCallStack)
EmitCallStackNotes(S, Fn);
} else if (PartialDiag) {
assert(ShowCallStack && "Must always show call stack for deferred diags.");
S.CUDADeferredDiags[Fn].push_back({Loc, std::move(*PartialDiag)});
}
}
// Do we know that we will eventually codegen the given function?
static bool IsKnownEmitted(Sema &S, FunctionDecl *FD) {
// Templates are emitted when they're instantiated.
if (FD->isDependentContext())
return false;
// When compiling for device, host functions are never emitted. Similarly,
// when compiling for host, device and global functions are never emitted.
// (Technically, we do emit a host-side stub for global functions, but this
// doesn't count for our purposes here.)
Sema::CUDAFunctionTarget T = S.IdentifyCUDATarget(FD);
if (S.getLangOpts().CUDAIsDevice && T == Sema::CFT_Host)
return false;
if (!S.getLangOpts().CUDAIsDevice &&
(T == Sema::CFT_Device || T == Sema::CFT_Global))
return false;
// Check whether this function is externally visible -- if so, it's
// known-emitted.
//
// We have to check the GVA linkage of the function's *definition* -- if we
// only have a declaration, we don't know whether or not the function will be
// emitted, because (say) the definition could include "inline".
FunctionDecl *Def = FD->getDefinition();
if (Def &&
!isDiscardableGVALinkage(S.getASTContext().GetGVALinkageForFunction(Def)))
return true;
// Otherwise, the function is known-emitted if it's in our set of
// known-emitted functions.
return S.CUDAKnownEmittedFns.count(FD) > 0;
}
Sema::CUDADiagBuilder Sema::CUDADiagIfDeviceCode(SourceLocation Loc,
unsigned DiagID) {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
CUDADiagBuilder::Kind DiagKind = [&] {
switch (CurrentCUDATarget()) {
case CFT_Global:
case CFT_Device:
return CUDADiagBuilder::K_Immediate;
case CFT_HostDevice:
// An HD function counts as host code if we're compiling for host, and
// device code if we're compiling for device. Defer any errors in device
// mode until the function is known-emitted.
if (getLangOpts().CUDAIsDevice) {
return IsKnownEmitted(*this, dyn_cast<FunctionDecl>(CurContext))
? CUDADiagBuilder::K_ImmediateWithCallStack
: CUDADiagBuilder::K_Deferred;
}
return CUDADiagBuilder::K_Nop;
default:
return CUDADiagBuilder::K_Nop;
}
}();
return CUDADiagBuilder(DiagKind, Loc, DiagID,
dyn_cast<FunctionDecl>(CurContext), *this);
}
Sema::CUDADiagBuilder Sema::CUDADiagIfHostCode(SourceLocation Loc,
unsigned DiagID) {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
CUDADiagBuilder::Kind DiagKind = [&] {
switch (CurrentCUDATarget()) {
case CFT_Host:
return CUDADiagBuilder::K_Immediate;
case CFT_HostDevice:
// An HD function counts as host code if we're compiling for host, and
// device code if we're compiling for device. Defer any errors in device
// mode until the function is known-emitted.
if (getLangOpts().CUDAIsDevice)
return CUDADiagBuilder::K_Nop;
return IsKnownEmitted(*this, dyn_cast<FunctionDecl>(CurContext))
? CUDADiagBuilder::K_ImmediateWithCallStack
: CUDADiagBuilder::K_Deferred;
default:
return CUDADiagBuilder::K_Nop;
}
}();
return CUDADiagBuilder(DiagKind, Loc, DiagID,
dyn_cast<FunctionDecl>(CurContext), *this);
}
// Emit any deferred diagnostics for FD and erase them from the map in which
// they're stored.
static void EmitDeferredDiags(Sema &S, FunctionDecl *FD) {
auto It = S.CUDADeferredDiags.find(FD);
if (It == S.CUDADeferredDiags.end())
return;
bool HasWarningOrError = false;
for (PartialDiagnosticAt &PDAt : It->second) {
const SourceLocation &Loc = PDAt.first;
const PartialDiagnostic &PD = PDAt.second;
HasWarningOrError |= S.getDiagnostics().getDiagnosticLevel(
PD.getDiagID(), Loc) >= DiagnosticsEngine::Warning;
DiagnosticBuilder Builder(S.Diags.Report(Loc, PD.getDiagID()));
Builder.setForceEmit();
PD.Emit(Builder);
}
S.CUDADeferredDiags.erase(It);
// FIXME: Should this be called after every warning/error emitted in the loop
// above, instead of just once per function? That would be consistent with
// how we handle immediate errors, but it also seems like a bit much.
if (HasWarningOrError)
EmitCallStackNotes(S, FD);
}
// Indicate that this function (and thus everything it transtively calls) will
// be codegen'ed, and emit any deferred diagnostics on this function and its
// (transitive) callees.
static void MarkKnownEmitted(Sema &S, FunctionDecl *OrigCaller,
FunctionDecl *OrigCallee, SourceLocation OrigLoc) {
// Nothing to do if we already know that FD is emitted.
if (IsKnownEmitted(S, OrigCallee)) {
assert(!S.CUDACallGraph.count(OrigCallee));
return;
}
// We've just discovered that OrigCallee is known-emitted. Walk our call
// graph to see what else we can now discover also must be emitted.
struct CallInfo {
FunctionDecl *Caller;
FunctionDecl *Callee;
SourceLocation Loc;
};
llvm::SmallVector<CallInfo, 4> Worklist = {{OrigCaller, OrigCallee, OrigLoc}};
llvm::SmallSet<CanonicalDeclPtr<FunctionDecl>, 4> Seen;
Seen.insert(OrigCallee);
while (!Worklist.empty()) {
CallInfo C = Worklist.pop_back_val();
assert(!IsKnownEmitted(S, C.Callee) &&
"Worklist should not contain known-emitted functions.");
S.CUDAKnownEmittedFns[C.Callee] = {C.Caller, C.Loc};
EmitDeferredDiags(S, C.Callee);
// If this is a template instantiation, explore its callgraph as well:
// Non-dependent calls are part of the template's callgraph, while dependent
// calls are part of to the instantiation's call graph.
if (auto *Templ = C.Callee->getPrimaryTemplate()) {
FunctionDecl *TemplFD = Templ->getAsFunction();
if (!Seen.count(TemplFD) && !S.CUDAKnownEmittedFns.count(TemplFD)) {
Seen.insert(TemplFD);
Worklist.push_back(
{/* Caller = */ C.Caller, /* Callee = */ TemplFD, C.Loc});
}
}
// Add all functions called by Callee to our worklist.
auto CGIt = S.CUDACallGraph.find(C.Callee);
if (CGIt == S.CUDACallGraph.end())
continue;
for (std::pair<CanonicalDeclPtr<FunctionDecl>, SourceLocation> FDLoc :
CGIt->second) {
FunctionDecl *NewCallee = FDLoc.first;
SourceLocation CallLoc = FDLoc.second;
if (Seen.count(NewCallee) || IsKnownEmitted(S, NewCallee))
continue;
Seen.insert(NewCallee);
Worklist.push_back(
{/* Caller = */ C.Callee, /* Callee = */ NewCallee, CallLoc});
}
// C.Callee is now known-emitted, so we no longer need to maintain its list
// of callees in CUDACallGraph.
S.CUDACallGraph.erase(CGIt);
}
}
bool Sema::CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee) {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
assert(Callee && "Callee may not be null.");
// FIXME: Is bailing out early correct here? Should we instead assume that
// the caller is a global initializer?
FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext);
if (!Caller)
return true;
// If the caller is known-emitted, mark the callee as known-emitted.
// Otherwise, mark the call in our call graph so we can traverse it later.
bool CallerKnownEmitted = IsKnownEmitted(*this, Caller);
if (CallerKnownEmitted) {
// Host-side references to a __global__ function refer to the stub, so the
// function itself is never emitted and therefore should not be marked.
if (getLangOpts().CUDAIsDevice || IdentifyCUDATarget(Callee) != CFT_Global)
MarkKnownEmitted(*this, Caller, Callee, Loc);
} else {
// If we have
// host fn calls kernel fn calls host+device,
// the HD function does not get instantiated on the host. We model this by
// omitting at the call to the kernel from the callgraph. This ensures
// that, when compiling for host, only HD functions actually called from the
// host get marked as known-emitted.
if (getLangOpts().CUDAIsDevice || IdentifyCUDATarget(Callee) != CFT_Global)
CUDACallGraph[Caller].insert({Callee, Loc});
}
CUDADiagBuilder::Kind DiagKind = [&] {
switch (IdentifyCUDAPreference(Caller, Callee)) {
case CFP_Never:
return CUDADiagBuilder::K_Immediate;
case CFP_WrongSide:
assert(Caller && "WrongSide calls require a non-null caller");
// If we know the caller will be emitted, we know this wrong-side call
// will be emitted, so it's an immediate error. Otherwise, defer the
// error until we know the caller is emitted.
return CallerKnownEmitted ? CUDADiagBuilder::K_ImmediateWithCallStack
: CUDADiagBuilder::K_Deferred;
default:
return CUDADiagBuilder::K_Nop;
}
}();
if (DiagKind == CUDADiagBuilder::K_Nop)
return true;
// Avoid emitting this error twice for the same location. Using a hashtable
// like this is unfortunate, but because we must continue parsing as normal
// after encountering a deferred error, it's otherwise very tricky for us to
// ensure that we only emit this deferred error once.
if (!LocsWithCUDACallDiags.insert({Caller, Loc}).second)
return true;
CUDADiagBuilder(DiagKind, Loc, diag::err_ref_bad_target, Caller, *this)
<< IdentifyCUDATarget(Callee) << Callee << IdentifyCUDATarget(Caller);
CUDADiagBuilder(DiagKind, Callee->getLocation(), diag::note_previous_decl,
Caller, *this)
<< Callee;
return DiagKind != CUDADiagBuilder::K_Immediate &&
DiagKind != CUDADiagBuilder::K_ImmediateWithCallStack;
}
void Sema::CUDASetLambdaAttrs(CXXMethodDecl *Method) {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
if (Method->hasAttr<CUDAHostAttr>() || Method->hasAttr<CUDADeviceAttr>())
return;
FunctionDecl *CurFn = dyn_cast<FunctionDecl>(CurContext);
if (!CurFn)
return;
CUDAFunctionTarget Target = IdentifyCUDATarget(CurFn);
if (Target == CFT_Global || Target == CFT_Device) {
Method->addAttr(CUDADeviceAttr::CreateImplicit(Context));
} else if (Target == CFT_HostDevice) {
Method->addAttr(CUDADeviceAttr::CreateImplicit(Context));
Method->addAttr(CUDAHostAttr::CreateImplicit(Context));
}
}
void Sema::checkCUDATargetOverload(FunctionDecl *NewFD,
const LookupResult &Previous) {
assert(getLangOpts().CUDA && "Should only be called during CUDA compilation");
CUDAFunctionTarget NewTarget = IdentifyCUDATarget(NewFD);
for (NamedDecl *OldND : Previous) {
FunctionDecl *OldFD = OldND->getAsFunction();
if (!OldFD)
continue;
CUDAFunctionTarget OldTarget = IdentifyCUDATarget(OldFD);
// Don't allow HD and global functions to overload other functions with the
// same signature. We allow overloading based on CUDA attributes so that
// functions can have different implementations on the host and device, but
// HD/global functions "exist" in some sense on both the host and device, so
// should have the same implementation on both sides.
if (NewTarget != OldTarget &&
((NewTarget == CFT_HostDevice) || (OldTarget == CFT_HostDevice) ||
(NewTarget == CFT_Global) || (OldTarget == CFT_Global)) &&
!IsOverload(NewFD, OldFD, /* UseMemberUsingDeclRules = */ false,
/* ConsiderCudaAttrs = */ false)) {
Diag(NewFD->getLocation(), diag::err_cuda_ovl_target)
<< NewTarget << NewFD->getDeclName() << OldTarget << OldFD;
Diag(OldFD->getLocation(), diag::note_previous_declaration);
NewFD->setInvalidDecl();
break;
}
}
}
template <typename AttrTy>
static void copyAttrIfPresent(Sema &S, FunctionDecl *FD,
const FunctionDecl &TemplateFD) {
if (AttrTy *Attribute = TemplateFD.getAttr<AttrTy>()) {
AttrTy *Clone = Attribute->clone(S.Context);
Clone->setInherited(true);
FD->addAttr(Clone);
}
}
void Sema::inheritCUDATargetAttrs(FunctionDecl *FD,
const FunctionTemplateDecl &TD) {
const FunctionDecl &TemplateFD = *TD.getTemplatedDecl();
copyAttrIfPresent<CUDAGlobalAttr>(*this, FD, TemplateFD);
copyAttrIfPresent<CUDAHostAttr>(*this, FD, TemplateFD);
copyAttrIfPresent<CUDADeviceAttr>(*this, FD, TemplateFD);
}
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