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 }
67 OS << ")\n";
68}
69
70TargetCodeGenInfo::TargetCodeGenInfo(std::unique_ptr<ABIInfo> Info)
71 : Info(std::move(Info)) {}
72
73TargetCodeGenInfo::~TargetCodeGenInfo() = default;
74
75// If someone can figure out a general rule for this, that would be great.
76// It's probably just doomed to be platform-dependent, though.
77unsigned TargetCodeGenInfo::getSizeOfUnwindException() const {
78 // Verified for:
79 // x86-64 FreeBSD, Linux, Darwin
80 // x86-32 FreeBSD, Linux, Darwin
81 // PowerPC Linux
82 // ARM Darwin (*not* EABI)
83 // AArch64 Linux
84 return 32;
85}
86
87bool TargetCodeGenInfo::isNoProtoCallVariadic(const CallArgList &args,
88 const FunctionNoProtoType *fnType) const {
89 // The following conventions are known to require this to be false:
90 // x86_stdcall
91 // MIPS
92 // For everything else, we just prefer false unless we opt out.
93 return false;
94}
95
96void
97TargetCodeGenInfo::getDependentLibraryOption(llvm::StringRef Lib,
98 llvm::SmallString<24> &Opt) const {
99 // This assumes the user is passing a library name like "rt" instead of a
100 // filename like "librt.a/so", and that they don't care whether it's static or
101 // dynamic.
102 Opt = "-l";
103 Opt += Lib;
104}
105
106unsigned TargetCodeGenInfo::getDeviceKernelCallingConv() const {
107 if (getABIInfo().getContext().getLangOpts().OpenCL) {
108 // Device kernels are called via an explicit runtime API with arguments,
109 // such as set with clSetKernelArg() for OpenCL, not as normal
110 // sub-functions. Return SPIR_KERNEL by default as the kernel calling
111 // convention to ensure the fingerprint is fixed such way that each kernel
112 // argument gets one matching argument in the produced kernel function
113 // argument list to enable feasible implementation of clSetKernelArg() with
114 // aggregates etc. In case we would use the default C calling conv here,
115 // clSetKernelArg() might break depending on the target-specific
116 // conventions; different targets might split structs passed as values
117 // to multiple function arguments etc.
118 return llvm::CallingConv::SPIR_KERNEL;
119 }
120 llvm_unreachable("Unknown kernel calling convention");
121}
122
123void TargetCodeGenInfo::setOCLKernelStubCallingConvention(
124 const FunctionType *&FT) const {
125 FT = getABIInfo().getContext().adjustFunctionType(
126 Fn: FT, EInfo: FT->getExtInfo().withCallingConv(cc: CC_C));
127}
128
129llvm::Constant *TargetCodeGenInfo::getNullPointer(const CodeGen::CodeGenModule &CGM,
130 llvm::PointerType *T, QualType QT) const {
131 return llvm::ConstantPointerNull::get(T);
132}
133
134LangAS TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
135 const VarDecl *D) const {
136 assert(!CGM.getLangOpts().OpenCL &&
137 !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
138 "Address space agnostic languages only");
139 return D ? D->getType().getAddressSpace() : LangAS::Default;
140}
141
142llvm::Value *TargetCodeGenInfo::performAddrSpaceCast(
143 CodeGen::CodeGenFunction &CGF, llvm::Value *Src, LangAS SrcAddr,
144 llvm::Type *DestTy, bool isNonNull) const {
145 // Since target may map different address spaces in AST to the same address
146 // space, an address space conversion may end up as a bitcast.
147 if (auto *C = dyn_cast<llvm::Constant>(Val: Src))
148 return performAddrSpaceCast(CGM&: CGF.CGM, V: C, SrcAddr, DestTy);
149 // Try to preserve the source's name to make IR more readable.
150 return CGF.Builder.CreateAddrSpaceCast(
151 V: Src, DestTy, Name: Src->hasName() ? Src->getName() + ".ascast" : "");
152}
153
154llvm::Constant *
155TargetCodeGenInfo::performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *Src,
156 LangAS SrcAddr,
157 llvm::Type *DestTy) const {
158 // Since target may map different address spaces in AST to the same address
159 // space, an address space conversion may end up as a bitcast.
160 return llvm::ConstantExpr::getPointerCast(C: Src, Ty: DestTy);
161}
162
163llvm::SyncScope::ID
164TargetCodeGenInfo::getLLVMSyncScopeID(const LangOptions &LangOpts,
165 SyncScope Scope,
166 llvm::AtomicOrdering Ordering,
167 llvm::LLVMContext &Ctx) const {
168 return Ctx.getOrInsertSyncScopeID(SSN: ""); /* default sync scope */
169}
170
171void TargetCodeGenInfo::addStackProbeTargetAttributes(
172 const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
173 if (llvm::Function *Fn = dyn_cast_or_null<llvm::Function>(Val: GV)) {
174 if (CGM.getCodeGenOpts().StackProbeSize != 4096)
175 Fn->addFnAttr(Kind: "stack-probe-size",
176 Val: llvm::utostr(X: CGM.getCodeGenOpts().StackProbeSize));
177 if (CGM.getCodeGenOpts().NoStackArgProbe)
178 Fn->addFnAttr(Kind: "no-stack-arg-probe");
179 }
180}
181
182/// Create an OpenCL kernel for an enqueued block.
183///
184/// The kernel has the same function type as the block invoke function. Its
185/// name is the name of the block invoke function postfixed with "_kernel".
186/// It simply calls the block invoke function then returns.
187llvm::Value *TargetCodeGenInfo::createEnqueuedBlockKernel(
188 CodeGenFunction &CGF, llvm::Function *Invoke, llvm::Type *BlockTy) const {
189 auto *InvokeFT = Invoke->getFunctionType();
190 auto &C = CGF.getLLVMContext();
191 std::string Name = Invoke->getName().str() + "_kernel";
192 auto *FT = llvm::FunctionType::get(Result: llvm::Type::getVoidTy(C),
193 Params: InvokeFT->params(), isVarArg: false);
194 auto *F = llvm::Function::Create(Ty: FT, Linkage: llvm::GlobalValue::ExternalLinkage, N: Name,
195 M: &CGF.CGM.getModule());
196 llvm::CallingConv::ID KernelCC =
197 CGF.getTypes().ClangCallConvToLLVMCallConv(CC: CallingConv::CC_DeviceKernel);
198 F->setCallingConv(KernelCC);
199
200 llvm::AttrBuilder KernelAttrs(C);
201
202 // FIXME: This is missing setTargetAttributes
203 CGF.CGM.addDefaultFunctionDefinitionAttributes(attrs&: KernelAttrs);
204 F->addFnAttrs(Attrs: KernelAttrs);
205
206 auto IP = CGF.Builder.saveIP();
207 auto *BB = llvm::BasicBlock::Create(Context&: C, Name: "entry", Parent: F);
208 auto &Builder = CGF.Builder;
209 Builder.SetInsertPoint(BB);
210 llvm::SmallVector<llvm::Value *, 2> Args(llvm::make_pointer_range(Range: F->args()));
211 llvm::CallInst *Call = Builder.CreateCall(Callee: Invoke, Args);
212 Call->setCallingConv(Invoke->getCallingConv());
213
214 Builder.CreateRetVoid();
215 Builder.restoreIP(IP);
216 return F;
217}
218
219void TargetCodeGenInfo::setBranchProtectionFnAttributes(
220 const TargetInfo::BranchProtectionInfo &BPI, llvm::Function &F) {
221 // Called on already created and initialized function where attributes already
222 // set from command line attributes but some might need to be removed as the
223 // actual BPI is different.
224 if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
225 F.addFnAttr(Kind: "sign-return-address", Val: BPI.getSignReturnAddrStr());
226 F.addFnAttr(Kind: "sign-return-address-key", Val: BPI.getSignKeyStr());
227 } else {
228 if (F.hasFnAttribute(Kind: "sign-return-address"))
229 F.removeFnAttr(Kind: "sign-return-address");
230 if (F.hasFnAttribute(Kind: "sign-return-address-key"))
231 F.removeFnAttr(Kind: "sign-return-address-key");
232 }
233
234 auto AddRemoveAttributeAsSet = [&](bool Set, const StringRef &ModAttr) {
235 if (Set)
236 F.addFnAttr(Kind: ModAttr);
237 else if (F.hasFnAttribute(Kind: ModAttr))
238 F.removeFnAttr(Kind: ModAttr);
239 };
240
241 AddRemoveAttributeAsSet(BPI.BranchTargetEnforcement,
242 "branch-target-enforcement");
243 AddRemoveAttributeAsSet(BPI.BranchProtectionPAuthLR,
244 "branch-protection-pauth-lr");
245 AddRemoveAttributeAsSet(BPI.GuardedControlStack, "guarded-control-stack");
246}
247
248void TargetCodeGenInfo::initBranchProtectionFnAttributes(
249 const TargetInfo::BranchProtectionInfo &BPI, llvm::AttrBuilder &FuncAttrs) {
250 // Only used for initializing attributes in the AttrBuilder, which will not
251 // contain any of these attributes so no need to remove anything.
252 if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
253 FuncAttrs.addAttribute(A: "sign-return-address", V: BPI.getSignReturnAddrStr());
254 FuncAttrs.addAttribute(A: "sign-return-address-key", V: BPI.getSignKeyStr());
255 }
256 if (BPI.BranchTargetEnforcement)
257 FuncAttrs.addAttribute(A: "branch-target-enforcement");
258 if (BPI.BranchProtectionPAuthLR)
259 FuncAttrs.addAttribute(A: "branch-protection-pauth-lr");
260 if (BPI.GuardedControlStack)
261 FuncAttrs.addAttribute(A: "guarded-control-stack");
262}
263
264void TargetCodeGenInfo::setPointerAuthFnAttributes(
265 const PointerAuthOptions &Opts, llvm::Function &F) {
266 auto UpdateAttr = [&F](bool AttrShouldExist, StringRef AttrName) {
267 if (AttrShouldExist && !F.hasFnAttribute(Kind: AttrName))
268 F.addFnAttr(Kind: AttrName);
269 if (!AttrShouldExist && F.hasFnAttribute(Kind: AttrName))
270 F.removeFnAttr(Kind: AttrName);
271 };
272 UpdateAttr(Opts.ReturnAddresses, "ptrauth-returns");
273 UpdateAttr((bool)Opts.FunctionPointers, "ptrauth-calls");
274 UpdateAttr(Opts.AuthTraps, "ptrauth-auth-traps");
275 UpdateAttr(Opts.IndirectGotos, "ptrauth-indirect-gotos");
276 UpdateAttr(Opts.AArch64JumpTableHardening, "aarch64-jump-table-hardening");
277}
278
279void TargetCodeGenInfo::initPointerAuthFnAttributes(
280 const PointerAuthOptions &Opts, llvm::AttrBuilder &FuncAttrs) {
281 if (Opts.ReturnAddresses)
282 FuncAttrs.addAttribute(A: "ptrauth-returns");
283 if (Opts.FunctionPointers)
284 FuncAttrs.addAttribute(A: "ptrauth-calls");
285 if (Opts.AuthTraps)
286 FuncAttrs.addAttribute(A: "ptrauth-auth-traps");
287 if (Opts.IndirectGotos)
288 FuncAttrs.addAttribute(A: "ptrauth-indirect-gotos");
289 if (Opts.AArch64JumpTableHardening)
290 FuncAttrs.addAttribute(A: "aarch64-jump-table-hardening");
291}
292
293namespace {
294class DefaultTargetCodeGenInfo : public TargetCodeGenInfo {
295public:
296 DefaultTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
297 : TargetCodeGenInfo(std::make_unique<DefaultABIInfo>(args&: CGT)) {}
298};
299} // namespace
300
301std::unique_ptr<TargetCodeGenInfo>
302CodeGen::createDefaultTargetCodeGenInfo(CodeGenModule &CGM) {
303 return std::make_unique<DefaultTargetCodeGenInfo>(args&: CGM.getTypes());
304}
305