1//===---- TargetInfo.cpp - Encapsulate target details -----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// These classes wrap the information about a call or function
10// definition used to handle ABI compliancy.
11//
12//===----------------------------------------------------------------------===//
13
14#include "TargetInfo.h"
15#include "ABIInfo.h"
16#include "ABIInfoImpl.h"
17#include "CodeGenFunction.h"
18#include "clang/Basic/CodeGenOptions.h"
19#include "clang/CodeGen/CGFunctionInfo.h"
20#include "llvm/ADT/StringExtras.h"
21#include "llvm/ADT/Twine.h"
22#include "llvm/IR/Function.h"
23#include "llvm/IR/Type.h"
24#include "llvm/Support/raw_ostream.h"
25
26using namespace clang;
27using namespace CodeGen;
28
29LLVM_DUMP_METHOD void ABIArgInfo::dump() const {
30 raw_ostream &OS = llvm::errs();
31 OS << "(ABIArgInfo Kind=";
32 switch (TheKind) {
33 case Direct:
34 OS << "Direct Type=";
35 if (llvm::Type *Ty = getCoerceToType())
36 Ty->print(O&: OS);
37 else
38 OS << "null";
39 break;
40 case Extend:
41 OS << "Extend";
42 break;
43 case Ignore:
44 OS << "Ignore";
45 break;
46 case InAlloca:
47 OS << "InAlloca Offset=" << getInAllocaFieldIndex();
48 break;
49 case Indirect:
50 OS << "Indirect Align=" << getIndirectAlign().getQuantity()
51 << " ByVal=" << getIndirectByVal()
52 << " Realign=" << getIndirectRealign();
53 break;
54 case IndirectAliased:
55 OS << "Indirect Align=" << getIndirectAlign().getQuantity()
56 << " AadrSpace=" << getIndirectAddrSpace()
57 << " Realign=" << getIndirectRealign();
58 break;
59 case Expand:
60 OS << "Expand";
61 break;
62 case CoerceAndExpand:
63 OS << "CoerceAndExpand Type=";
64 getCoerceAndExpandType()->print(O&: OS);
65 break;
66 case TargetSpecific:
67 OS << "TargetSpecific Type=";
68 if (llvm::Type *Ty = getCoerceToType())
69 Ty->print(O&: OS);
70 else
71 OS << "null";
72 break;
73 }
74 OS << ")\n";
75}
76
77TargetCodeGenInfo::TargetCodeGenInfo(std::unique_ptr<ABIInfo> Info)
78 : Info(std::move(Info)) {}
79
80TargetCodeGenInfo::~TargetCodeGenInfo() = default;
81
82// If someone can figure out a general rule for this, that would be great.
83// It's probably just doomed to be platform-dependent, though.
84unsigned TargetCodeGenInfo::getSizeOfUnwindException() const {
85 if (getABIInfo().getCodeGenOpts().hasSEHExceptions())
86 return getABIInfo().getDataLayout().getPointerSizeInBits() > 32 ? 64 : 48;
87 // Verified for:
88 // x86-64 FreeBSD, Linux, Darwin
89 // x86-32 FreeBSD, Linux, Darwin
90 // PowerPC Linux
91 // ARM Darwin (*not* EABI)
92 // AArch64 Linux
93 return 32;
94}
95
96bool TargetCodeGenInfo::isNoProtoCallVariadic(const CallArgList &args,
97 const FunctionNoProtoType *fnType) const {
98 // The following conventions are known to require this to be false:
99 // x86_stdcall
100 // MIPS
101 // For everything else, we just prefer false unless we opt out.
102 return false;
103}
104
105void
106TargetCodeGenInfo::getDependentLibraryOption(llvm::StringRef Lib,
107 llvm::SmallString<24> &Opt) const {
108 // This assumes the user is passing a library name like "rt" instead of a
109 // filename like "librt.a/so", and that they don't care whether it's static or
110 // dynamic.
111 Opt = "-l";
112 Opt += Lib;
113}
114
115unsigned TargetCodeGenInfo::getDeviceKernelCallingConv() const {
116 // Device kernels are called via an explicit runtime API with arguments,
117 // such as set with clSetKernelArg() for OpenCL, not as normal
118 // sub-functions. This uses a modified version of the C calling convention
119 // which simplifies the treatment of non-scalar types. (The rule adjustment
120 // hapens in CodeGenTypes::arrangeLLVMFunctionInfo.)
121 //
122 // Outside of OpenCL, kernels currently do not exist for CPU targets.
123 assert(getABIInfo().getContext().getLangOpts().OpenCL &&
124 "Kernel calling convention only defined for OpenCL");
125 return llvm::CallingConv::C;
126}
127
128void TargetCodeGenInfo::setOCLKernelStubCallingConvention(
129 const FunctionType *&FT) const {
130 FT = getABIInfo().getContext().adjustFunctionType(
131 Fn: FT, EInfo: FT->getExtInfo().withCallingConv(cc: CC_C));
132}
133
134llvm::Constant *TargetCodeGenInfo::getNullPointer(const CodeGen::CodeGenModule &CGM,
135 llvm::PointerType *T, QualType QT) const {
136 return llvm::ConstantPointerNull::get(T);
137}
138
139LangAS TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
140 const VarDecl *D) const {
141 assert(!CGM.getLangOpts().OpenCL &&
142 !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
143 "Address space agnostic languages only");
144 return D ? D->getType().getAddressSpace() : LangAS::Default;
145}
146
147StringRef
148TargetCodeGenInfo::getLLVMSyncScopeStr(const LangOptions &LangOpts,
149 SyncScope Scope,
150 llvm::AtomicOrdering Ordering) const {
151 return ""; /* default sync scope */
152}
153
154llvm::SyncScope::ID
155TargetCodeGenInfo::getLLVMSyncScopeID(const LangOptions &LangOpts,
156 SyncScope Scope,
157 llvm::AtomicOrdering Ordering,
158 llvm::LLVMContext &Ctx) const {
159 return Ctx.getOrInsertSyncScopeID(
160 SSN: getLLVMSyncScopeStr(LangOpts, Scope, Ordering));
161}
162
163void TargetCodeGenInfo::addStackProbeTargetAttributes(
164 const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
165 if (llvm::Function *Fn = dyn_cast_or_null<llvm::Function>(Val: GV)) {
166 if (CGM.getCodeGenOpts().StackProbeSize != 4096)
167 Fn->addFnAttr(Kind: "stack-probe-size",
168 Val: llvm::utostr(X: CGM.getCodeGenOpts().StackProbeSize));
169 if (CGM.getCodeGenOpts().NoStackArgProbe)
170 Fn->addFnAttr(Kind: "no-stack-arg-probe");
171 }
172}
173
174/// Create an OpenCL kernel for an enqueued block.
175///
176/// The kernel has the same function type as the block invoke function. Its
177/// name is the name of the block invoke function postfixed with "_kernel".
178/// It simply calls the block invoke function then returns.
179llvm::Value *TargetCodeGenInfo::createEnqueuedBlockKernel(
180 CodeGenFunction &CGF, llvm::Function *Invoke, llvm::Type *BlockTy) const {
181 auto *InvokeFT = Invoke->getFunctionType();
182 auto &C = CGF.getLLVMContext();
183 std::string Name = Invoke->getName().str() + "_kernel";
184 auto *FT = llvm::FunctionType::get(Result: llvm::Type::getVoidTy(C),
185 Params: InvokeFT->params(), isVarArg: false);
186 auto *F = llvm::Function::Create(Ty: FT, Linkage: llvm::GlobalValue::ExternalLinkage, N: Name,
187 M: &CGF.CGM.getModule());
188 llvm::CallingConv::ID KernelCC =
189 CGF.getTypes().ClangCallConvToLLVMCallConv(CC: CallingConv::CC_DeviceKernel);
190 F->setCallingConv(KernelCC);
191
192 llvm::AttrBuilder KernelAttrs(C);
193
194 // FIXME: This is missing setTargetAttributes
195 CGF.CGM.addDefaultFunctionDefinitionAttributes(attrs&: KernelAttrs);
196 F->addFnAttrs(Attrs: KernelAttrs);
197
198 if (CGF.Builder.getIsFPConstrained())
199 F->addFnAttr(Kind: llvm::Attribute::StrictFP);
200
201 auto IP = CGF.Builder.saveIP();
202 auto *BB = llvm::BasicBlock::Create(Context&: C, Name: "entry", Parent: F);
203 auto &Builder = CGF.Builder;
204 Builder.SetInsertPoint(BB);
205 llvm::SmallVector<llvm::Value *, 2> Args(llvm::make_pointer_range(Range: F->args()));
206 llvm::CallInst *Call = Builder.CreateCall(Callee: Invoke, Args);
207 Call->setCallingConv(Invoke->getCallingConv());
208
209 Builder.CreateRetVoid();
210 Builder.restoreIP(IP);
211 return F;
212}
213
214void TargetCodeGenInfo::setBranchProtectionFnAttributes(
215 const TargetInfo::BranchProtectionInfo &BPI, llvm::Function &F) {
216 // Called on already created and initialized function where attributes already
217 // set from command line attributes but some might need to be removed as the
218 // actual BPI is different.
219 if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
220 F.addFnAttr(Kind: "sign-return-address", Val: BPI.getSignReturnAddrStr());
221 F.addFnAttr(Kind: "sign-return-address-key", Val: BPI.getSignKeyStr());
222 } else {
223 if (F.hasFnAttribute(Kind: "sign-return-address"))
224 F.removeFnAttr(Kind: "sign-return-address");
225 if (F.hasFnAttribute(Kind: "sign-return-address-key"))
226 F.removeFnAttr(Kind: "sign-return-address-key");
227 }
228
229 auto AddRemoveAttributeAsSet = [&](bool Set, const StringRef &ModAttr) {
230 if (Set)
231 F.addFnAttr(Kind: ModAttr);
232 else if (F.hasFnAttribute(Kind: ModAttr))
233 F.removeFnAttr(Kind: ModAttr);
234 };
235
236 AddRemoveAttributeAsSet(BPI.BranchTargetEnforcement,
237 "branch-target-enforcement");
238 AddRemoveAttributeAsSet(BPI.BranchProtectionPAuthLR,
239 "branch-protection-pauth-lr");
240 AddRemoveAttributeAsSet(BPI.GuardedControlStack, "guarded-control-stack");
241}
242
243void TargetCodeGenInfo::initBranchProtectionFnAttributes(
244 const TargetInfo::BranchProtectionInfo &BPI, llvm::AttrBuilder &FuncAttrs) {
245 // Only used for initializing attributes in the AttrBuilder, which will not
246 // contain any of these attributes so no need to remove anything.
247 if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
248 FuncAttrs.addAttribute(A: "sign-return-address", V: BPI.getSignReturnAddrStr());
249 FuncAttrs.addAttribute(A: "sign-return-address-key", V: BPI.getSignKeyStr());
250 }
251 if (BPI.BranchTargetEnforcement)
252 FuncAttrs.addAttribute(A: "branch-target-enforcement");
253 if (BPI.BranchProtectionPAuthLR)
254 FuncAttrs.addAttribute(A: "branch-protection-pauth-lr");
255 if (BPI.GuardedControlStack)
256 FuncAttrs.addAttribute(A: "guarded-control-stack");
257}
258
259void TargetCodeGenInfo::setPointerAuthFnAttributes(
260 const PointerAuthOptions &Opts, llvm::Function &F) {
261 auto UpdateAttr = [&F](bool AttrShouldExist, StringRef AttrName) {
262 if (AttrShouldExist && !F.hasFnAttribute(Kind: AttrName))
263 F.addFnAttr(Kind: AttrName);
264 if (!AttrShouldExist && F.hasFnAttribute(Kind: AttrName))
265 F.removeFnAttr(Kind: AttrName);
266 };
267 UpdateAttr(Opts.ReturnAddresses, "ptrauth-returns");
268 UpdateAttr((bool)Opts.FunctionPointers, "ptrauth-calls");
269 UpdateAttr(Opts.AuthTraps, "ptrauth-auth-traps");
270 UpdateAttr(Opts.IndirectGotos, "ptrauth-indirect-gotos");
271 UpdateAttr(Opts.AArch64JumpTableHardening, "aarch64-jump-table-hardening");
272}
273
274void TargetCodeGenInfo::initPointerAuthFnAttributes(
275 const PointerAuthOptions &Opts, llvm::AttrBuilder &FuncAttrs) {
276 if (Opts.ReturnAddresses)
277 FuncAttrs.addAttribute(A: "ptrauth-returns");
278 if (Opts.FunctionPointers)
279 FuncAttrs.addAttribute(A: "ptrauth-calls");
280 if (Opts.AuthTraps)
281 FuncAttrs.addAttribute(A: "ptrauth-auth-traps");
282 if (Opts.IndirectGotos)
283 FuncAttrs.addAttribute(A: "ptrauth-indirect-gotos");
284 if (Opts.AArch64JumpTableHardening)
285 FuncAttrs.addAttribute(A: "aarch64-jump-table-hardening");
286}
287
288namespace {
289class DefaultTargetCodeGenInfo : public TargetCodeGenInfo {
290public:
291 DefaultTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
292 : TargetCodeGenInfo(std::make_unique<DefaultABIInfo>(args&: CGT)) {}
293};
294} // namespace
295
296std::unique_ptr<TargetCodeGenInfo>
297CodeGen::createDefaultTargetCodeGenInfo(CodeGenModule &CGM) {
298 return std::make_unique<DefaultTargetCodeGenInfo>(args&: CGM.getTypes());
299}
300