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view gen/dvalue.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 | 30b42a283c8e |
children | 3cf0066e6faf |
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#ifndef LDC_GEN_DVALUE_H #define LDC_GEN_DVALUE_H /* These classes are used for generating the IR. They encapsulate D values and provide a common interface to the most common operations. When more specialized handling is necessary, they hold enough information to do-the-right-thing (TM) */ #include <cassert> #include "root.h" struct Type; struct Dsymbol; struct VarDeclaration; struct FuncDeclaration; namespace llvm { class Value; class Type; class Constant; } struct DImValue; struct DConstValue; struct DNullValue; struct DVarValue; struct DFieldValue; struct DFuncValue; struct DSliceValue; struct DLRValue; // base class for d-values struct DValue : Object { virtual Type*& getType() = 0; virtual LLValue* getLVal() { assert(0); return 0; } virtual LLValue* getRVal() { assert(0); return 0; } virtual bool isLVal() { return false; } virtual DImValue* isIm() { return NULL; } virtual DConstValue* isConst() { return NULL; } virtual DNullValue* isNull() { return NULL; } virtual DVarValue* isVar() { return NULL; } virtual DFieldValue* isField() { return NULL; } virtual DSliceValue* isSlice() { return NULL; } virtual DFuncValue* isFunc() { return NULL; } virtual DLRValue* isLRValue() { return NULL; } protected: DValue() {} DValue(const DValue&) { } DValue& operator=(const DValue&) { return *this; } }; // immediate d-value struct DImValue : DValue { Type* type; LLValue* val; DImValue(Type* t, LLValue* v) : type(t), val(v) { } virtual LLValue* getRVal() { assert(val); return val; } virtual Type*& getType() { assert(type); return type; } virtual DImValue* isIm() { return this; } }; // constant d-value struct DConstValue : DValue { Type* type; LLConstant* c; DConstValue(Type* t, LLConstant* con) { type = t; c = con; } virtual LLValue* getRVal(); virtual Type*& getType() { assert(type); return type; } virtual DConstValue* isConst() { return this; } }; // null d-value struct DNullValue : DConstValue { DNullValue(Type* t, LLConstant* con) : DConstValue(t,con) {} virtual DNullValue* isNull() { return this; } }; // variable d-value struct DVarValue : DValue { Type* type; VarDeclaration* var; LLValue* val; DVarValue(Type* t, VarDeclaration* vd, LLValue* llvmValue); DVarValue(Type* t, LLValue* llvmValue); virtual bool isLVal() { return true; } virtual LLValue* getLVal(); virtual LLValue* getRVal(); virtual Type*& getType() { assert(type); return type; } virtual DVarValue* isVar() { return this; } }; // field d-value struct DFieldValue : DVarValue { DFieldValue(Type* t, LLValue* llvmValue) : DVarValue(t, llvmValue) {} virtual DFieldValue* isField() { return this; } }; // slice d-value struct DSliceValue : DValue { Type* type; LLValue* len; LLValue* ptr; DSliceValue(Type* t, LLValue* l, LLValue* p) { type=t; ptr=p; len=l; } virtual LLValue* getRVal(); virtual Type*& getType() { assert(type); return type; } virtual DSliceValue* isSlice() { return this; } }; // function d-value struct DFuncValue : DValue { Type* type; FuncDeclaration* func; LLValue* val; LLValue* vthis; DFuncValue(FuncDeclaration* fd, LLValue* v, LLValue* vt = 0); virtual LLValue* getRVal(); virtual Type*& getType() { assert(type); return type; } virtual DFuncValue* isFunc() { return this; } }; // l-value and r-value pair d-value struct DLRValue : DValue { DValue* lvalue; DValue* rvalue; DLRValue(DValue* lval, DValue* rval) { lvalue = lval; rvalue = rval; } virtual bool isLVal() { return true; } virtual LLValue* getLVal() { return lvalue->isLVal() ? lvalue->getLVal() : lvalue->getRVal(); } virtual LLValue* getRVal() { return rvalue->getRVal(); } Type*& getLType(); Type*& getRType() { return rvalue->getType(); } virtual Type*& getType() { return getRType(); } virtual DLRValue* isLRValue() { return this; } }; #endif // LDC_GEN_DVALUE_H