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view ir/irfuncty.h @ 1117:4c20fcc4252b
Fun with parameter attributes: For several of the "synthetic" parameters added
to D functions, we can apply noalias and nocapture. They are sret parameters,
'nest' pointers passed to nested functions, and _argptr:
Nocapture:
- Sret and nest are nocapture because they don't represent D-level variables,
and thus the callee can't (validly) obtain a pointer to them, let alone keep
it around after it returns.
- _argptr is nocapture because although the callee has access to it as a
pointer, that pointer is invalidated when it returns.
All three are noalias because they're function-local variables
- Sret and _argptr are noalias because they're freshly alloca'd memory only
used for a single function call that's not allowed to keep an aliasing
pointer to it around (since the parameter is nocapture).
- 'Nest' is noalias because the callee only ever has access to one such pointer
per parent function, and every parent function has a different one.
This commit also ensures attributes set on sret, _arguments and _argptr are
propagated to calls to such functions.
It also adds one exception to the general rule that attributes on function types
should propagate to calls: the type of a delegate's function pointer has a
'nest' parameter, but this can either be a true 'nest' (for delegates to nested
functions) or a 'this' (for delegates to member functions). Since 'this' is
neither noalias nor nocapture, and there's generally no way to tell which one it
is, we remove these attributes at the call site if the callee is a delegate.
author | Frits van Bommel <fvbommel wxs.nl> |
---|---|
date | Sat, 14 Mar 2009 22:15:31 +0100 |
parents | dc608dc33081 |
children |
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#ifndef LDC_IR_IRFUNCTY_H #define LDC_IR_IRFUNCTY_H #include "ir/ir.h" #include "llvm/ADT/SmallVector.h" #include <vector> struct ABIRewrite; namespace llvm { class Type; class Value; class Instruction; class Function; } // represents a function type argument // both explicit and implicit as well as return values struct IrFuncTyArg : IrBase { /** This is the original D type as the frontend knows it * May NOT be rewritten!!! */ Type* type; /// This is the final LLVM Type used for the parameter/return value type const llvm::Type* ltype; /** These are the final LLVM attributes used for the function. * Must be valid for the LLVM Type and byref setting */ unsigned attrs; /** 'true' if the final LLVM argument is a LLVM reference type. * Must be true when the D Type is a value type, but the final * LLVM Type is a reference type! */ bool byref; /** Pointer to the ABIRewrite structure needed to rewrite LLVM ValueS * to match the final LLVM Type when passing arguments and getting * return values */ ABIRewrite* rewrite; /// Helper to check if the 'inreg' attribute is set bool isInReg() const; /// Helper to check if the 'sret' attribute is set bool isSRet() const; /// Helper to check if the 'byval' attribute is set bool isByVal() const; /** @param t D type of argument/return value as known by the frontend * @param byref Initial value for the 'byref' field. If true the initial * LLVM Type will be of DtoType(type->pointerTo()), instead * of just DtoType(type) */ IrFuncTyArg(Type* t, bool byref, unsigned a = 0); }; // represents a function type struct IrFuncTy : IrBase { // return value IrFuncTyArg* ret; // null if not applicable IrFuncTyArg* arg_sret; IrFuncTyArg* arg_this; IrFuncTyArg* arg_nest; IrFuncTyArg* arg_arguments; IrFuncTyArg* arg_argptr; // normal explicit arguments // typedef llvm::SmallVector<IrFuncTyArg*, 4> ArgList; typedef std::vector<IrFuncTyArg*> ArgList; typedef ArgList::iterator ArgIter; ArgList args; // C varargs bool c_vararg; // range of normal parameters to reverse bool reverseParams; IrFuncTy() : ret(NULL), arg_sret(NULL), arg_this(NULL), arg_nest(NULL), arg_arguments(NULL), arg_argptr(NULL), c_vararg(false), reverseParams(false) {} void reset() { ret = NULL; arg_sret = arg_this = arg_nest = arg_arguments = arg_argptr = NULL; args.clear(); c_vararg = false; reverseParams = false; } llvm::Value* putRet(Type* dty, DValue* dval); llvm::Value* getRet(Type* dty, DValue* dval); llvm::Value* putParam(Type* dty, int idx, DValue* dval); llvm::Value* getParam(Type* dty, int idx, DValue* dval); void getParam(Type* dty, int idx, DValue* dval, llvm::Value* lval); }; #endif