clang/lib/CodeGen/TargetInfo.cpp

   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/Type.h"
  23 #include "llvm/Support/raw_ostream.h"
  24
  25 using namespace clang;
  26 using namespace CodeGen;
  27
  28 LLVM_DUMP_METHOD void ABIArgInfo::dump() const {
  29   raw_ostream &OS = llvm::errs();
  30   OS << "(ABIArgInfo Kind=";
  31   switch (TheKind) {
  32   case Direct:
  33     OS << "Direct Type=";
  34     if (llvm::Type *Ty = getCoerceToType())
  35       Ty->print(OS);
  36     else
  37       OS << "null";
  38     break;
  39   case Extend:
  40     OS << "Extend";
  41     break;
  42   case Ignore:
  43     OS << "Ignore";
  44     break;
  45   case InAlloca:
  46     OS << "InAlloca Offset=" << getInAllocaFieldIndex();
  47     break;
  48   case Indirect:
  49     OS << "Indirect Align=" << getIndirectAlign().getQuantity()
  50        << " ByVal=" << getIndirectByVal()
  51        << " Realign=" << getIndirectRealign();
  52     break;
  53   case IndirectAliased:
  54     OS << "Indirect Align=" << getIndirectAlign().getQuantity()
  55        << " AadrSpace=" << getIndirectAddrSpace()
  56        << " Realign=" << getIndirectRealign();
  57     break;
  58   case Expand:
  59     OS << "Expand";
  60     break;
  61   case CoerceAndExpand:
  62     OS << "CoerceAndExpand Type=";
  63     getCoerceAndExpandType()->print(OS);
  64     break;
  65   }
  66   OS << ")\n";
  67 }
  68
  69 TargetCodeGenInfo::TargetCodeGenInfo(std::unique_ptr<ABIInfo> Info)
  70     : Info(std::move(Info)) {}
  71
  72 TargetCodeGenInfo::~TargetCodeGenInfo() = default;
  73
  74 // If someone can figure out a general rule for this, that would be great.
  75 // It's probably just doomed to be platform-dependent, though.
  76 unsigned TargetCodeGenInfo::getSizeOfUnwindException() const {
  77   // Verified for:
  78   //   x86-64     FreeBSD, Linux, Darwin
  79   //   x86-32     FreeBSD, Linux, Darwin
  80   //   PowerPC    Linux
  81   //   ARM        Darwin (*not* EABI)
  82   //   AArch64    Linux
  83   return 32;
  84 }
  85
  86 bool TargetCodeGenInfo::isNoProtoCallVariadic(const CallArgList &args,
  87                                      const FunctionNoProtoType *fnType) const {
  88   // The following conventions are known to require this to be false:
  89   //   x86_stdcall
  90   //   MIPS
  91   // For everything else, we just prefer false unless we opt out.
  92   return false;
  93 }
  94
  95 void
  96 TargetCodeGenInfo::getDependentLibraryOption(llvm::StringRef Lib,
  97                                              llvm::SmallString<24> &Opt) const {
  98   // This assumes the user is passing a library name like "rt" instead of a
  99   // filename like "librt.a/so", and that they don't care whether it's static or
 100   // dynamic.
 101   Opt = "-l";
 102   Opt += Lib;
 103 }
 104
 105 unsigned TargetCodeGenInfo::getOpenCLKernelCallingConv() const {
 106   // OpenCL kernels are called via an explicit runtime API with arguments
 107   // set with clSetKernelArg(), not as normal sub-functions.
 108   // Return SPIR_KERNEL by default as the kernel calling convention to
 109   // ensure the fingerprint is fixed such way that each OpenCL argument
 110   // gets one matching argument in the produced kernel function argument
 111   // list to enable feasible implementation of clSetKernelArg() with
 112   // aggregates etc. In case we would use the default C calling conv here,
 113   // clSetKernelArg() might break depending on the target-specific
 114   // conventions; different targets might split structs passed as values
 115   // to multiple function arguments etc.
 116   return llvm::CallingConv::SPIR_KERNEL;
 117 }
 118
 119 llvm::Constant *TargetCodeGenInfo::getNullPointer(const CodeGen::CodeGenModule &CGM,
 120     llvm::PointerType *T, QualType QT) const {
 121   return llvm::ConstantPointerNull::get(T);
 122 }
 123
 124 LangAS TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
 125                                                    const VarDecl *D) const {
 126   assert(!CGM.getLangOpts().OpenCL &&
 127          !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
 128          "Address space agnostic languages only");
 129   return D ? D->getType().getAddressSpace() : LangAS::Default;
 130 }
 131
 132 llvm::Value *TargetCodeGenInfo::performAddrSpaceCast(
 133     CodeGen::CodeGenFunction &CGF, llvm::Value *Src, LangAS SrcAddr,
 134     LangAS DestAddr, llvm::Type *DestTy, bool isNonNull) const {
 135   // Since target may map different address spaces in AST to the same address
 136   // space, an address space conversion may end up as a bitcast.
 137   if (auto *C = dyn_cast<llvm::Constant>(Src))
 138     return performAddrSpaceCast(CGF.CGM, C, SrcAddr, DestAddr, DestTy);
 139   // Try to preserve the source's name to make IR more readable.
 140   return CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(
 141       Src, DestTy, Src->hasName() ? Src->getName() + ".ascast" : "");
 142 }
 143
 144 llvm::Constant *
 145 TargetCodeGenInfo::performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *Src,
 146                                         LangAS SrcAddr, LangAS DestAddr,
 147                                         llvm::Type *DestTy) const {
 148   // Since target may map different address spaces in AST to the same address
 149   // space, an address space conversion may end up as a bitcast.
 150   return llvm::ConstantExpr::getPointerCast(Src, DestTy);
 151 }
 152
 153 llvm::SyncScope::ID
 154 TargetCodeGenInfo::getLLVMSyncScopeID(const LangOptions &LangOpts,
 155                                       SyncScope Scope,
 156                                       llvm::AtomicOrdering Ordering,
 157                                       llvm::LLVMContext &Ctx) const {
 158   return Ctx.getOrInsertSyncScopeID(""); /* default sync scope */
 159 }
 160
 161 void TargetCodeGenInfo::addStackProbeTargetAttributes(
 162     const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
 163   if (llvm::Function *Fn = dyn_cast_or_null<llvm::Function>(GV)) {
 164     if (CGM.getCodeGenOpts().StackProbeSize != 4096)
 165       Fn->addFnAttr("stack-probe-size",
 166                     llvm::utostr(CGM.getCodeGenOpts().StackProbeSize));
 167     if (CGM.getCodeGenOpts().NoStackArgProbe)
 168       Fn->addFnAttr("no-stack-arg-probe");
 169   }
 170 }
 171
 172 /// Create an OpenCL kernel for an enqueued block.
 173 ///
 174 /// The kernel has the same function type as the block invoke function. Its
 175 /// name is the name of the block invoke function postfixed with "_kernel".
 176 /// It simply calls the block invoke function then returns.
 177 llvm::Value *TargetCodeGenInfo::createEnqueuedBlockKernel(
 178     CodeGenFunction &CGF, llvm::Function *Invoke, llvm::Type *BlockTy) const {
 179   auto *InvokeFT = Invoke->getFunctionType();
 180   auto &C = CGF.getLLVMContext();
 181   std::string Name = Invoke->getName().str() + "_kernel";
 182   auto *FT = llvm::FunctionType::get(llvm::Type::getVoidTy(C),
 183                                      InvokeFT->params(), false);
 184   auto *F = llvm::Function::Create(FT, llvm::GlobalValue::ExternalLinkage, Name,
 185                                    &CGF.CGM.getModule());
 186   llvm::CallingConv::ID KernelCC =
 187       CGF.getTypes().ClangCallConvToLLVMCallConv(CallingConv::CC_OpenCLKernel);
 188   F->setCallingConv(KernelCC);
 189
 190   llvm::AttrBuilder KernelAttrs(C);
 191
 192   // FIXME: This is missing setTargetAttributes
 193   CGF.CGM.addDefaultFunctionDefinitionAttributes(KernelAttrs);
 194   F->addFnAttrs(KernelAttrs);
 195
 196   auto IP = CGF.Builder.saveIP();
 197   auto *BB = llvm::BasicBlock::Create(C, "entry", F);
 198   auto &Builder = CGF.Builder;
 199   Builder.SetInsertPoint(BB);
 200   llvm::SmallVector<llvm::Value *, 2> Args(llvm::make_pointer_range(F->args()));
 201   llvm::CallInst *Call = Builder.CreateCall(Invoke, Args);
 202   Call->setCallingConv(Invoke->getCallingConv());
 203
 204   Builder.CreateRetVoid();
 205   Builder.restoreIP(IP);
 206   return F;
 207 }
 208
 209 namespace {
 210 class DefaultTargetCodeGenInfo : public TargetCodeGenInfo {
 211 public:
 212   DefaultTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
 213       : TargetCodeGenInfo(std::make_unique<DefaultABIInfo>(CGT)) {}
 214 };
 215 } // namespace
 216
 217 std::unique_ptr<TargetCodeGenInfo>
 218 CodeGen::createDefaultTargetCodeGenInfo(CodeGenModule &CGM) {
 219   return std::make_unique<DefaultTargetCodeGenInfo>(CGM.getTypes());
 220 }