clang/lib/CodeGen/TargetInfo.h - toolchain/llvm-project - Gitiles

 //===---- TargetInfo.h - Encapsulate target details -------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // These classes wrap the information about a call or function
 // definition used to handle ABI compliancy.
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H
 #define LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H

 #include "CGValue.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/LLVM.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"

 namespace llvm {
 class Constant;
 class GlobalValue;
 class Type;
 class Value;
 }

 namespace clang {
 class ABIInfo;
 class Decl;

 namespace CodeGen {
 class CallArgList;
 class CodeGenModule;
 class CodeGenFunction;
 class CGFunctionInfo;
 }

 /// TargetCodeGenInfo - This class organizes various target-specific
 /// codegeneration issues, like target-specific attributes, builtins and so
 /// on.
 class TargetCodeGenInfo {
   ABIInfo *Info;

 public:
   // WARNING: Acquires the ownership of ABIInfo.
   TargetCodeGenInfo(ABIInfo *info = 0) : Info(info) {}
   virtual ~TargetCodeGenInfo();

   /// getABIInfo() - Returns ABI info helper for the target.
   const ABIInfo &getABIInfo() const { return *Info; }

   /// SetTargetAttributes - Provides a convenient hook to handle extra
   /// target-specific attributes for the given global.
   virtual void SetTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
                                    CodeGen::CodeGenModule &M) const {}

   /// EmitTargetMD - Provides a convenient hook to handle extra
   /// target-specific metadata for the given global.
   virtual void emitTargetMD(const Decl *D, llvm::GlobalValue *GV,
                             CodeGen::CodeGenModule &M) const {}

   /// Determines the size of struct _Unwind_Exception on this platform,
   /// in 8-bit units.  The Itanium ABI defines this as:
   ///   struct _Unwind_Exception {
   ///     uint64 exception_class;
   ///     _Unwind_Exception_Cleanup_Fn exception_cleanup;
   ///     uint64 private_1;
   ///     uint64 private_2;
   ///   };
   virtual unsigned getSizeOfUnwindException() const;

   /// Controls whether __builtin_extend_pointer should sign-extend
   /// pointers to uint64_t or zero-extend them (the default).  Has
   /// no effect for targets:
   ///   - that have 64-bit pointers, or
   ///   - that cannot address through registers larger than pointers, or
   ///   - that implicitly ignore/truncate the top bits when addressing
   ///     through such registers.
   virtual bool extendPointerWithSExt() const { return false; }

   /// Determines the DWARF register number for the stack pointer, for
   /// exception-handling purposes.  Implements __builtin_dwarf_sp_column.
   ///
   /// Returns -1 if the operation is unsupported by this target.
   virtual int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const {
     return -1;
   }

   /// Initializes the given DWARF EH register-size table, a char*.
   /// Implements __builtin_init_dwarf_reg_size_table.
   ///
   /// Returns true if the operation is unsupported by this target.
   virtual bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
                                        llvm::Value *Address) const {
     return true;
   }

   /// Performs the code-generation required to convert a return
   /// address as stored by the system into the actual address of the
   /// next instruction that will be executed.
   ///
   /// Used by __builtin_extract_return_addr().
   virtual llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF,
                                            llvm::Value *Address) const {
     return Address;
   }

   /// Performs the code-generation required to convert the address
   /// of an instruction into a return address suitable for storage
   /// by the system in a return slot.
   ///
   /// Used by __builtin_frob_return_addr().
   virtual llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF,
                                            llvm::Value *Address) const {
     return Address;
   }

   /// Corrects the low-level LLVM type for a given constraint and "usual"
   /// type.
   ///
   /// \returns A pointer to a new LLVM type, possibly the same as the original
   /// on success; 0 on failure.
   virtual llvm::Type *adjustInlineAsmType(CodeGen::CodeGenFunction &CGF,
                                           StringRef Constraint,
                                           llvm::Type *Ty) const {
     return Ty;
   }

   /// Adds constraints and types for result registers.
   virtual void addReturnRegisterOutputs(
       CodeGen::CodeGenFunction &CGF, CodeGen::LValue ReturnValue,
       std::string &Constraints, std::vector<llvm::Type *> &ResultRegTypes,
       std::vector<llvm::Type *> &ResultTruncRegTypes,
       std::vector<CodeGen::LValue> &ResultRegDests, std::string &AsmString,
       unsigned NumOutputs) const {}

   /// doesReturnSlotInterfereWithArgs - Return true if the target uses an
   /// argument slot for an 'sret' type.
   virtual bool doesReturnSlotInterfereWithArgs() const { return true; }

   /// Retrieve the address of a function to call immediately before
   /// calling objc_retainAutoreleasedReturnValue.  The
   /// implementation of objc_autoreleaseReturnValue sniffs the
   /// instruction stream following its return address to decide
   /// whether it's a call to objc_retainAutoreleasedReturnValue.
   /// This can be prohibitively expensive, depending on the
   /// relocation model, and so on some targets it instead sniffs for
   /// a particular instruction sequence.  This functions returns
   /// that instruction sequence in inline assembly, which will be
   /// empty if none is required.
   virtual StringRef getARCRetainAutoreleasedReturnValueMarker() const {
     return "";
   }

   /// Return a constant used by UBSan as a signature to identify functions
   /// possessing type information, or 0 if the platform is unsupported.
   virtual llvm::Constant *
   getUBSanFunctionSignature(CodeGen::CodeGenModule &CGM) const {
     return nullptr;
   }

   /// Determine whether a call to an unprototyped functions under
   /// the given calling convention should use the variadic
   /// convention or the non-variadic convention.
   ///
   /// There's a good reason to make a platform's variadic calling
   /// convention be different from its non-variadic calling
   /// convention: the non-variadic arguments can be passed in
   /// registers (better for performance), and the variadic arguments
   /// can be passed on the stack (also better for performance).  If
   /// this is done, however, unprototyped functions *must* use the
   /// non-variadic convention, because C99 states that a call
   /// through an unprototyped function type must succeed if the
   /// function was defined with a non-variadic prototype with
   /// compatible parameters.  Therefore, splitting the conventions
   /// makes it impossible to call a variadic function through an
   /// unprototyped type.  Since function prototypes came out in the
   /// late 1970s, this is probably an acceptable trade-off.
   /// Nonetheless, not all platforms are willing to make it, and in
   /// particularly x86-64 bends over backwards to make the
   /// conventions compatible.
   ///
   /// The default is false.  This is correct whenever:
   ///   - the conventions are exactly the same, because it does not
   ///     matter and the resulting IR will be somewhat prettier in
   ///     certain cases; or
   ///   - the conventions are substantively different in how they pass
   ///     arguments, because in this case using the variadic convention
   ///     will lead to C99 violations.
   ///
   /// However, some platforms make the conventions identical except
   /// for passing additional out-of-band information to a variadic
   /// function: for example, x86-64 passes the number of SSE
   /// arguments in %al.  On these platforms, it is desirable to
   /// call unprototyped functions using the variadic convention so
   /// that unprototyped calls to varargs functions still succeed.
   ///
   /// Relatedly, platforms which pass the fixed arguments to this:
   ///   A foo(B, C, D);
   /// differently than they would pass them to this:
   ///   A foo(B, C, D, ...);
   /// may need to adjust the debugger-support code in Sema to do the
   /// right thing when calling a function with no know signature.
   virtual bool isNoProtoCallVariadic(const CodeGen::CallArgList &args,
                                      const FunctionNoProtoType *fnType) const;

   /// Gets the linker options necessary to link a dependent library on this
   /// platform.
   virtual void getDependentLibraryOption(llvm::StringRef Lib,
                                          llvm::SmallString<24> &Opt) const;

   /// Gets the linker options necessary to detect object file mismatches on
   /// this platform.
   virtual void getDetectMismatchOption(llvm::StringRef Name,
                                        llvm::StringRef Value,
                                        llvm::SmallString<32> &Opt) const {}

   /// Gets the target-specific default alignment used when an 'aligned' clause
   /// is used with a 'simd' OpenMP directive without specifying a specific
   /// alignment.
   virtual unsigned getOpenMPSimdDefaultAlignment(QualType Type) const {
     return 0;
   }
 };
 }

 #endif
	//===---- TargetInfo.h - Encapsulate target details -------------- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// These classes wrap the information about a call or function
	// definition used to handle ABI compliancy.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H
	#define LLVM_CLANG_LIB_CODEGEN_TARGETINFO_H

	#include "CGValue.h"
	#include "clang/AST/Type.h"
	#include "clang/Basic/LLVM.h"
	#include "llvm/ADT/SmallString.h"
	#include "llvm/ADT/StringRef.h"

	namespace llvm {
	class Constant;
	class GlobalValue;
	class Type;
	class Value;
	}

	namespace clang {
	class ABIInfo;
	class Decl;

	namespace CodeGen {
	class CallArgList;
	class CodeGenModule;
	class CodeGenFunction;
	class CGFunctionInfo;
	}

	/// TargetCodeGenInfo - This class organizes various target-specific
	/// codegeneration issues, like target-specific attributes, builtins and so
	/// on.
	class TargetCodeGenInfo {
	ABIInfo *Info;

	public:
	// WARNING: Acquires the ownership of ABIInfo.
	TargetCodeGenInfo(ABIInfo *info = 0) : Info(info) {}
	virtual ~TargetCodeGenInfo();

	/// getABIInfo() - Returns ABI info helper for the target.
	const ABIInfo &getABIInfo() const { return *Info; }

	/// SetTargetAttributes - Provides a convenient hook to handle extra
	/// target-specific attributes for the given global.
	virtual void SetTargetAttributes(const Decl D, llvm::GlobalValue GV,
	CodeGen::CodeGenModule &M) const {}

	/// EmitTargetMD - Provides a convenient hook to handle extra
	/// target-specific metadata for the given global.
	virtual void emitTargetMD(const Decl D, llvm::GlobalValue GV,
	CodeGen::CodeGenModule &M) const {}

	/// Determines the size of struct _Unwind_Exception on this platform,
	/// in 8-bit units. The Itanium ABI defines this as:
	/// struct _Unwind_Exception {
	/// uint64 exception_class;
	/// _Unwind_Exception_Cleanup_Fn exception_cleanup;
	/// uint64 private_1;
	/// uint64 private_2;
	/// };
	virtual unsigned getSizeOfUnwindException() const;

	/// Controls whether __builtin_extend_pointer should sign-extend
	/// pointers to uint64_t or zero-extend them (the default). Has
	/// no effect for targets:
	/// - that have 64-bit pointers, or
	/// - that cannot address through registers larger than pointers, or
	/// - that implicitly ignore/truncate the top bits when addressing
	/// through such registers.
	virtual bool extendPointerWithSExt() const { return false; }

	/// Determines the DWARF register number for the stack pointer, for
	/// exception-handling purposes. Implements __builtin_dwarf_sp_column.
	///
	/// Returns -1 if the operation is unsupported by this target.
	virtual int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const {
	return -1;
	}

	/// Initializes the given DWARF EH register-size table, a char*.
	/// Implements __builtin_init_dwarf_reg_size_table.
	///
	/// Returns true if the operation is unsupported by this target.
	virtual bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
	llvm::Value *Address) const {
	return true;
	}

	/// Performs the code-generation required to convert a return
	/// address as stored by the system into the actual address of the
	/// next instruction that will be executed.
	///
	/// Used by __builtin_extract_return_addr().
	virtual llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF,
	llvm::Value *Address) const {
	return Address;
	}

	/// Performs the code-generation required to convert the address
	/// of an instruction into a return address suitable for storage
	/// by the system in a return slot.
	///
	/// Used by __builtin_frob_return_addr().
	virtual llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF,
	llvm::Value *Address) const {
	return Address;
	}

	/// Corrects the low-level LLVM type for a given constraint and "usual"
	/// type.
	///
	/// \returns A pointer to a new LLVM type, possibly the same as the original
	/// on success; 0 on failure.
	virtual llvm::Type *adjustInlineAsmType(CodeGen::CodeGenFunction &CGF,
	StringRef Constraint,
	llvm::Type *Ty) const {
	return Ty;
	}

	/// Adds constraints and types for result registers.
	virtual void addReturnRegisterOutputs(
	CodeGen::CodeGenFunction &CGF, CodeGen::LValue ReturnValue,
	std::string &Constraints, std::vector<llvm::Type *> &ResultRegTypes,
	std::vector<llvm::Type *> &ResultTruncRegTypes,
	std::vector<CodeGen::LValue> &ResultRegDests, std::string &AsmString,
	unsigned NumOutputs) const {}

	/// doesReturnSlotInterfereWithArgs - Return true if the target uses an
	/// argument slot for an 'sret' type.
	virtual bool doesReturnSlotInterfereWithArgs() const { return true; }

	/// Retrieve the address of a function to call immediately before
	/// calling objc_retainAutoreleasedReturnValue. The
	/// implementation of objc_autoreleaseReturnValue sniffs the
	/// instruction stream following its return address to decide
	/// whether it's a call to objc_retainAutoreleasedReturnValue.
	/// This can be prohibitively expensive, depending on the
	/// relocation model, and so on some targets it instead sniffs for
	/// a particular instruction sequence. This functions returns
	/// that instruction sequence in inline assembly, which will be
	/// empty if none is required.
	virtual StringRef getARCRetainAutoreleasedReturnValueMarker() const {
	return "";
	}

	/// Return a constant used by UBSan as a signature to identify functions
	/// possessing type information, or 0 if the platform is unsupported.
	virtual llvm::Constant *
	getUBSanFunctionSignature(CodeGen::CodeGenModule &CGM) const {
	return nullptr;
	}

	/// Determine whether a call to an unprototyped functions under
	/// the given calling convention should use the variadic
	/// convention or the non-variadic convention.
	///
	/// There's a good reason to make a platform's variadic calling
	/// convention be different from its non-variadic calling
	/// convention: the non-variadic arguments can be passed in
	/// registers (better for performance), and the variadic arguments
	/// can be passed on the stack (also better for performance). If
	/// this is done, however, unprototyped functions must use the
	/// non-variadic convention, because C99 states that a call
	/// through an unprototyped function type must succeed if the
	/// function was defined with a non-variadic prototype with
	/// compatible parameters. Therefore, splitting the conventions
	/// makes it impossible to call a variadic function through an
	/// unprototyped type. Since function prototypes came out in the
	/// late 1970s, this is probably an acceptable trade-off.
	/// Nonetheless, not all platforms are willing to make it, and in
	/// particularly x86-64 bends over backwards to make the
	/// conventions compatible.
	///
	/// The default is false. This is correct whenever:
	/// - the conventions are exactly the same, because it does not
	/// matter and the resulting IR will be somewhat prettier in
	/// certain cases; or
	/// - the conventions are substantively different in how they pass
	/// arguments, because in this case using the variadic convention
	/// will lead to C99 violations.
	///
	/// However, some platforms make the conventions identical except
	/// for passing additional out-of-band information to a variadic
	/// function: for example, x86-64 passes the number of SSE
	/// arguments in %al. On these platforms, it is desirable to
	/// call unprototyped functions using the variadic convention so
	/// that unprototyped calls to varargs functions still succeed.
	///
	/// Relatedly, platforms which pass the fixed arguments to this:
	/// A foo(B, C, D);
	/// differently than they would pass them to this:
	/// A foo(B, C, D, ...);
	/// may need to adjust the debugger-support code in Sema to do the
	/// right thing when calling a function with no know signature.
	virtual bool isNoProtoCallVariadic(const CodeGen::CallArgList &args,
	const FunctionNoProtoType *fnType) const;

	/// Gets the linker options necessary to link a dependent library on this
	/// platform.
	virtual void getDependentLibraryOption(llvm::StringRef Lib,
	llvm::SmallString<24> &Opt) const;

	/// Gets the linker options necessary to detect object file mismatches on
	/// this platform.
	virtual void getDetectMismatchOption(llvm::StringRef Name,
	llvm::StringRef Value,
	llvm::SmallString<32> &Opt) const {}

	/// Gets the target-specific default alignment used when an 'aligned' clause
	/// is used with a 'simd' OpenMP directive without specifying a specific
	/// alignment.
	virtual unsigned getOpenMPSimdDefaultAlignment(QualType Type) const {
	return 0;
	}
	};
	}

	#endif