Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/clang/lib/CodeGen/TargetInfo.h
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//===---- TargetInfo.h - Encapsulate target details -------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// These classes wrap the information about a call or function
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// definition used to handle ABI compliancy.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H
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#define LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H
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#include "CodeGenModule.h"
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#include "CGValue.h"
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#include "clang/AST/Type.h"
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#include "clang/Basic/LLVM.h"
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#include "clang/Basic/SyncScope.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/StringRef.h"
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namespace llvm {
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class Constant;
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class GlobalValue;
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class Type;
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class Value;
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}
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namespace clang {
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class Decl;
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namespace CodeGen {
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class ABIInfo;
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class CallArgList;
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class CodeGenFunction;
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class CGBlockInfo;
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class CGFunctionInfo;
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/// TargetCodeGenInfo - This class organizes various target-specific
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/// codegeneration issues, like target-specific attributes, builtins and so
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/// on.
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class TargetCodeGenInfo {
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  ABIInfo *Info;
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public:
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  // WARNING: Acquires the ownership of ABIInfo.
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  TargetCodeGenInfo(ABIInfo *info = nullptr) : Info(info) {}
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  virtual ~TargetCodeGenInfo();
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  /// getABIInfo() - Returns ABI info helper for the target.
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  const ABIInfo &getABIInfo() const { return *Info; }
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  /// setTargetAttributes - Provides a convenient hook to handle extra
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  /// target-specific attributes for the given global.
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  virtual void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
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                                   CodeGen::CodeGenModule &M) const {}
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  /// emitTargetMD - Provides a convenient hook to handle extra
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  /// target-specific metadata for the given global.
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  virtual void emitTargetMD(const Decl *D, llvm::GlobalValue *GV,
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                            CodeGen::CodeGenModule &M) const {}
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  /// Determines the size of struct _Unwind_Exception on this platform,
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  /// in 8-bit units.  The Itanium ABI defines this as:
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  ///   struct _Unwind_Exception {
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  ///     uint64 exception_class;
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  ///     _Unwind_Exception_Cleanup_Fn exception_cleanup;
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  ///     uint64 private_1;
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  ///     uint64 private_2;
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  ///   };
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  virtual unsigned getSizeOfUnwindException() const;
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  /// Controls whether __builtin_extend_pointer should sign-extend
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  /// pointers to uint64_t or zero-extend them (the default).  Has
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  /// no effect for targets:
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  ///   - that have 64-bit pointers, or
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  ///   - that cannot address through registers larger than pointers, or
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  ///   - that implicitly ignore/truncate the top bits when addressing
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  ///     through such registers.
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  virtual bool extendPointerWithSExt() const { return false; }
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  /// Determines the DWARF register number for the stack pointer, for
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  /// exception-handling purposes.  Implements __builtin_dwarf_sp_column.
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  ///
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  /// Returns -1 if the operation is unsupported by this target.
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  virtual int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const {
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    return -1;
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  }
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  /// Initializes the given DWARF EH register-size table, a char*.
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  /// Implements __builtin_init_dwarf_reg_size_table.
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  ///
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  /// Returns true if the operation is unsupported by this target.
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  virtual bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
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                                       llvm::Value *Address) const {
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    return true;
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  }
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  /// Performs the code-generation required to convert a return
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  /// address as stored by the system into the actual address of the
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  /// next instruction that will be executed.
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  ///
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  /// Used by __builtin_extract_return_addr().
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  virtual llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF,
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                                           llvm::Value *Address) const {
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    return Address;
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  }
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  /// Performs the code-generation required to convert the address
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  /// of an instruction into a return address suitable for storage
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  /// by the system in a return slot.
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  ///
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  /// Used by __builtin_frob_return_addr().
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  virtual llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF,
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                                           llvm::Value *Address) const {
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    return Address;
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  }
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  /// Corrects the low-level LLVM type for a given constraint and "usual"
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  /// type.
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  ///
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  /// \returns A pointer to a new LLVM type, possibly the same as the original
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  /// on success; 0 on failure.
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  virtual llvm::Type *adjustInlineAsmType(CodeGen::CodeGenFunction &CGF,
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                                          StringRef Constraint,
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                                          llvm::Type *Ty) const {
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    return Ty;
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  }
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  /// Adds constraints and types for result registers.
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  virtual void addReturnRegisterOutputs(
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      CodeGen::CodeGenFunction &CGF, CodeGen::LValue ReturnValue,
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      std::string &Constraints, std::vector<llvm::Type *> &ResultRegTypes,
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      std::vector<llvm::Type *> &ResultTruncRegTypes,
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      std::vector<CodeGen::LValue> &ResultRegDests, std::string &AsmString,
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      unsigned NumOutputs) const {}
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  /// doesReturnSlotInterfereWithArgs - Return true if the target uses an
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  /// argument slot for an 'sret' type.
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  virtual bool doesReturnSlotInterfereWithArgs() const { return true; }
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  /// Retrieve the address of a function to call immediately before
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  /// calling objc_retainAutoreleasedReturnValue.  The
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  /// implementation of objc_autoreleaseReturnValue sniffs the
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  /// instruction stream following its return address to decide
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  /// whether it's a call to objc_retainAutoreleasedReturnValue.
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  /// This can be prohibitively expensive, depending on the
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  /// relocation model, and so on some targets it instead sniffs for
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  /// a particular instruction sequence.  This functions returns
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  /// that instruction sequence in inline assembly, which will be
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  /// empty if none is required.
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  virtual StringRef getARCRetainAutoreleasedReturnValueMarker() const {
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    return "";
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  }
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  /// Determine whether a call to objc_retainAutoreleasedReturnValue should be
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  /// marked as 'notail'.
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  virtual bool shouldSuppressTailCallsOfRetainAutoreleasedReturnValue() const {
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    return false;
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  }
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  /// Return a constant used by UBSan as a signature to identify functions
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  /// possessing type information, or 0 if the platform is unsupported.
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  virtual llvm::Constant *
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  getUBSanFunctionSignature(CodeGen::CodeGenModule &CGM) const {
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    return nullptr;
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  }
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  /// Determine whether a call to an unprototyped functions under
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  /// the given calling convention should use the variadic
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  /// convention or the non-variadic convention.
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  ///
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  /// There's a good reason to make a platform's variadic calling
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  /// convention be different from its non-variadic calling
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  /// convention: the non-variadic arguments can be passed in
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  /// registers (better for performance), and the variadic arguments
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  /// can be passed on the stack (also better for performance).  If
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  /// this is done, however, unprototyped functions *must* use the
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  /// non-variadic convention, because C99 states that a call
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  /// through an unprototyped function type must succeed if the
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  /// function was defined with a non-variadic prototype with
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  /// compatible parameters.  Therefore, splitting the conventions
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  /// makes it impossible to call a variadic function through an
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  /// unprototyped type.  Since function prototypes came out in the
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  /// late 1970s, this is probably an acceptable trade-off.
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  /// Nonetheless, not all platforms are willing to make it, and in
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  /// particularly x86-64 bends over backwards to make the
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  /// conventions compatible.
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  ///
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  /// The default is false.  This is correct whenever:
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  ///   - the conventions are exactly the same, because it does not
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  ///     matter and the resulting IR will be somewhat prettier in
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  ///     certain cases; or
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  ///   - the conventions are substantively different in how they pass
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  ///     arguments, because in this case using the variadic convention
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  ///     will lead to C99 violations.
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  ///
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  /// However, some platforms make the conventions identical except
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  /// for passing additional out-of-band information to a variadic
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  /// function: for example, x86-64 passes the number of SSE
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  /// arguments in %al.  On these platforms, it is desirable to
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  /// call unprototyped functions using the variadic convention so
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  /// that unprototyped calls to varargs functions still succeed.
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  ///
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  /// Relatedly, platforms which pass the fixed arguments to this:
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  ///   A foo(B, C, D);
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  /// differently than they would pass them to this:
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  ///   A foo(B, C, D, ...);
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  /// may need to adjust the debugger-support code in Sema to do the
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  /// right thing when calling a function with no know signature.
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  virtual bool isNoProtoCallVariadic(const CodeGen::CallArgList &args,
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                                     const FunctionNoProtoType *fnType) const;
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  /// Gets the linker options necessary to link a dependent library on this
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  /// platform.
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  virtual void getDependentLibraryOption(llvm::StringRef Lib,
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                                         llvm::SmallString<24> &Opt) const;
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  /// Gets the linker options necessary to detect object file mismatches on
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  /// this platform.
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  virtual void getDetectMismatchOption(llvm::StringRef Name,
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                                       llvm::StringRef Value,
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                                       llvm::SmallString<32> &Opt) const {}
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  /// Get LLVM calling convention for OpenCL kernel.
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  virtual unsigned getOpenCLKernelCallingConv() const;
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  /// Get target specific null pointer.
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  /// \param T is the LLVM type of the null pointer.
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  /// \param QT is the clang QualType of the null pointer.
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  /// \return ConstantPointerNull with the given type \p T.
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  /// Each target can override it to return its own desired constant value.
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  virtual llvm::Constant *getNullPointer(const CodeGen::CodeGenModule &CGM,
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      llvm::PointerType *T, QualType QT) const;
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  /// Get target favored AST address space of a global variable for languages
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  /// other than OpenCL and CUDA.
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  /// If \p D is nullptr, returns the default target favored address space
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  /// for global variable.
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  virtual LangAS getGlobalVarAddressSpace(CodeGenModule &CGM,
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                                          const VarDecl *D) const;
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  /// Get the AST address space for alloca.
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  virtual LangAS getASTAllocaAddressSpace() const { return LangAS::Default; }
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  /// Perform address space cast of an expression of pointer type.
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  /// \param V is the LLVM value to be casted to another address space.
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  /// \param SrcAddr is the language address space of \p V.
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  /// \param DestAddr is the targeted language address space.
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  /// \param DestTy is the destination LLVM pointer type.
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  /// \param IsNonNull is the flag indicating \p V is known to be non null.
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  virtual llvm::Value *performAddrSpaceCast(CodeGen::CodeGenFunction &CGF,
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                                            llvm::Value *V, LangAS SrcAddr,
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                                            LangAS DestAddr, llvm::Type *DestTy,
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                                            bool IsNonNull = false) const;
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  /// Perform address space cast of a constant expression of pointer type.
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  /// \param V is the LLVM constant to be casted to another address space.
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  /// \param SrcAddr is the language address space of \p V.
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  /// \param DestAddr is the targeted language address space.
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  /// \param DestTy is the destination LLVM pointer type.
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  virtual llvm::Constant *performAddrSpaceCast(CodeGenModule &CGM,
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                                               llvm::Constant *V,
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                                               LangAS SrcAddr, LangAS DestAddr,
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                                               llvm::Type *DestTy) const;
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  /// Get address space of pointer parameter for __cxa_atexit.
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  virtual LangAS getAddrSpaceOfCxaAtexitPtrParam() const {
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    return LangAS::Default;
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  }
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  /// Get the syncscope used in LLVM IR.
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  virtual llvm::SyncScope::ID getLLVMSyncScopeID(const LangOptions &LangOpts,
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                                                 SyncScope Scope,
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                                                 llvm::AtomicOrdering Ordering,
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                                                 llvm::LLVMContext &Ctx) const;
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  /// Interface class for filling custom fields of a block literal for OpenCL.
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  class TargetOpenCLBlockHelper {
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  public:
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    typedef std::pair<llvm::Value *, StringRef> ValueTy;
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    TargetOpenCLBlockHelper() {}
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    virtual ~TargetOpenCLBlockHelper() {}
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    /// Get the custom field types for OpenCL blocks.
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    virtual llvm::SmallVector<llvm::Type *, 1> getCustomFieldTypes() = 0;
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    /// Get the custom field values for OpenCL blocks.
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    virtual llvm::SmallVector<ValueTy, 1>
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    getCustomFieldValues(CodeGenFunction &CGF, const CGBlockInfo &Info) = 0;
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    virtual bool areAllCustomFieldValuesConstant(const CGBlockInfo &Info) = 0;
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    /// Get the custom field values for OpenCL blocks if all values are LLVM
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    /// constants.
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    virtual llvm::SmallVector<llvm::Constant *, 1>
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    getCustomFieldValues(CodeGenModule &CGM, const CGBlockInfo &Info) = 0;
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  };
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  virtual TargetOpenCLBlockHelper *getTargetOpenCLBlockHelper() const {
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    return nullptr;
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  }
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  /// Create an OpenCL kernel for an enqueued block. The kernel function is
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  /// a wrapper for the block invoke function with target-specific calling
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  /// convention and ABI as an OpenCL kernel. The wrapper function accepts
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  /// block context and block arguments in target-specific way and calls
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  /// the original block invoke function.
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  virtual llvm::Function *
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  createEnqueuedBlockKernel(CodeGenFunction &CGF,
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                            llvm::Function *BlockInvokeFunc,
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                            llvm::Value *BlockLiteral) const;
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  /// \return true if the target supports alias from the unmangled name to the
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  /// mangled name of functions declared within an extern "C" region and marked
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  /// as 'used', and having internal linkage.
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  virtual bool shouldEmitStaticExternCAliases() const { return true; }
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  virtual void setCUDAKernelCallingConvention(const FunctionType *&FT) const {}
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};
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} // namespace CodeGen
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} // namespace clang
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#endif // LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H