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view dmd/struct.c @ 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 | b30fe7e1dbb9 |
children | 1860414bf3b7 |
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// Compiler implementation of the D programming language // Copyright (c) 1999-2009 by Digital Mars // All Rights Reserved // written by Walter Bright // http://www.digitalmars.com // License for redistribution is by either the Artistic License // in artistic.txt, or the GNU General Public License in gnu.txt. // See the included readme.txt for details. #include <stdio.h> #include <assert.h> #include "root.h" #include "aggregate.h" #include "scope.h" #include "mtype.h" #include "declaration.h" #include "module.h" #include "id.h" #include "statement.h" /********************************* AggregateDeclaration ****************************/ AggregateDeclaration::AggregateDeclaration(Loc loc, Identifier *id) : ScopeDsymbol(id) { this->loc = loc; storage_class = 0; protection = PROTpublic; type = NULL; handle = NULL; structsize = 0; // size of struct alignsize = 0; // size of struct for alignment purposes structalign = 0; // struct member alignment in effect hasUnions = 0; sizeok = 0; // size not determined yet isdeprecated = 0; inv = NULL; aggNew = NULL; aggDelete = NULL; stag = NULL; sinit = NULL; scope = NULL; #if V2 dtor = NULL; ctor = NULL; defaultCtor = NULL; #endif } enum PROT AggregateDeclaration::prot() { return protection; } void AggregateDeclaration::semantic2(Scope *sc) { //printf("AggregateDeclaration::semantic2(%s)\n", toChars()); if (scope) { error("has forward references"); return; } if (members) { sc = sc->push(this); for (size_t i = 0; i < members->dim; i++) { Dsymbol *s = (Dsymbol *)members->data[i]; s->semantic2(sc); } sc->pop(); } } void AggregateDeclaration::semantic3(Scope *sc) { int i; //printf("AggregateDeclaration::semantic3(%s)\n", toChars()); if (members) { sc = sc->push(this); for (i = 0; i < members->dim; i++) { Dsymbol *s = (Dsymbol *)members->data[i]; s->semantic3(sc); } sc->pop(); } } void AggregateDeclaration::inlineScan() { int i; //printf("AggregateDeclaration::inlineScan(%s)\n", toChars()); if (members) { for (i = 0; i < members->dim; i++) { Dsymbol *s = (Dsymbol *)members->data[i]; //printf("inline scan aggregate symbol '%s'\n", s->toChars()); s->inlineScan(); } } } unsigned AggregateDeclaration::size(Loc loc) { //printf("AggregateDeclaration::size() = %d\n", structsize); if (!members) error(loc, "unknown size"); if (sizeok != 1) { error(loc, "no size yet for forward reference"); //*(char*)0=0; } return structsize; } Type *AggregateDeclaration::getType() { return type; } int AggregateDeclaration::isDeprecated() { return isdeprecated; } /**************************** * Do byte or word alignment as necessary. * Align sizes of 0, as we may not know array sizes yet. */ void AggregateDeclaration::alignmember( unsigned salign, // struct alignment that is in effect unsigned size, // alignment requirement of field unsigned *poffset) { //printf("salign = %d, size = %d, offset = %d\n",salign,size,offset); if (salign > 1) { assert(size != 3); int sa = size; if (sa == 0 || salign < sa) sa = salign; *poffset = (*poffset + sa - 1) & ~(sa - 1); } //printf("result = %d\n",offset); } void AggregateDeclaration::addField(Scope *sc, VarDeclaration *v) { unsigned memsize; // size of member unsigned memalignsize; // size of member for alignment purposes unsigned xalign; // alignment boundaries //printf("AggregateDeclaration::addField('%s') %s\n", v->toChars(), toChars()); // Check for forward referenced types which will fail the size() call Type *t = v->type->toBasetype(); if (t->ty == Tstruct /*&& isStructDeclaration()*/) { TypeStruct *ts = (TypeStruct *)t; #if V2 if (ts->sym == this) { error("cannot have field %s with same struct type", v->toChars()); } #endif if (ts->sym->sizeok != 1) { sizeok = 2; // cannot finish; flag as forward referenced return; } } if (t->ty == Tident) { sizeok = 2; // cannot finish; flag as forward referenced return; } memsize = v->type->size(loc); memalignsize = v->type->alignsize(); xalign = v->type->memalign(sc->structalign); alignmember(xalign, memalignsize, &sc->offset); v->offset = sc->offset; sc->offset += memsize; if (sc->offset > structsize) structsize = sc->offset; if (sc->structalign < memalignsize) memalignsize = sc->structalign; if (alignsize < memalignsize) alignsize = memalignsize; //printf("\talignsize = %d\n", alignsize); v->storage_class |= STCfield; //printf(" addField '%s' to '%s' at offset %d, size = %d\n", v->toChars(), toChars(), v->offset, memsize); fields.push(v); } /********************************* StructDeclaration ****************************/ StructDeclaration::StructDeclaration(Loc loc, Identifier *id) : AggregateDeclaration(loc, id) { zeroInit = 0; // assume false until we do semantic processing #if V2 hasIdentityAssign = 0; cpctor = NULL; postblit = NULL; #endif // For forward references type = new TypeStruct(this); } Dsymbol *StructDeclaration::syntaxCopy(Dsymbol *s) { StructDeclaration *sd; if (s) sd = (StructDeclaration *)s; else sd = new StructDeclaration(loc, ident); ScopeDsymbol::syntaxCopy(sd); return sd; } void StructDeclaration::semantic(Scope *sc) { int i; Scope *sc2; //printf("+StructDeclaration::semantic(this=%p, '%s')\n", this, toChars()); //static int count; if (++count == 20) *(char*)0=0; assert(type); if (!members) // if forward reference return; if (symtab) { if (!scope) return; // semantic() already completed } else symtab = new DsymbolTable(); Scope *scx = NULL; if (scope) { sc = scope; scx = scope; // save so we don't make redundant copies scope = NULL; } parent = sc->parent; #if STRUCTTHISREF handle = type; #else handle = type->pointerTo(); #endif structalign = sc->structalign; protection = sc->protection; if (sc->stc & STCdeprecated) isdeprecated = 1; assert(!isAnonymous()); if (sc->stc & STCabstract) error("structs, unions cannot be abstract"); #if V2 if (storage_class & STCinvariant) type = type->invariantOf(); else if (storage_class & STCconst) type = type->constOf(); #endif if (sizeok == 0) // if not already done the addMember step { for (i = 0; i < members->dim; i++) { Dsymbol *s = (Dsymbol *)members->data[i]; //printf("adding member '%s' to '%s'\n", s->toChars(), this->toChars()); s->addMember(sc, this, 1); } } sizeok = 0; sc2 = sc->push(this); sc2->stc = 0; sc2->parent = this; if (isUnionDeclaration()) sc2->inunion = 1; sc2->protection = PROTpublic; sc2->explicitProtection = 0; int members_dim = members->dim; for (i = 0; i < members_dim; i++) { Dsymbol *s = (Dsymbol *)members->data[i]; s->semantic(sc2); if (isUnionDeclaration()) sc2->offset = 0; #if 0 if (sizeok == 2) { //printf("forward reference\n"); break; } #endif } /* The TypeInfo_Struct is expecting an opEquals and opCmp with * a parameter that is a pointer to the struct. But if there * isn't one, but is an opEquals or opCmp with a value, write * another that is a shell around the value: * int opCmp(struct *p) { return opCmp(*p); } */ TypeFunction *tfeqptr; { Arguments *arguments = new Arguments; Argument *arg = new Argument(STCin, handle, Id::p, NULL); arguments->push(arg); tfeqptr = new TypeFunction(arguments, Type::tint32, 0, LINKd); tfeqptr = (TypeFunction *)tfeqptr->semantic(0, sc); } TypeFunction *tfeq; { Arguments *arguments = new Arguments; Argument *arg = new Argument(STCin, type, NULL, NULL); arguments->push(arg); tfeq = new TypeFunction(arguments, Type::tint32, 0, LINKd); tfeq = (TypeFunction *)tfeq->semantic(0, sc); } Identifier *id = Id::eq; for (int i = 0; i < 2; i++) { Dsymbol *s = search_function(this, id); FuncDeclaration *fdx = s ? s->isFuncDeclaration() : NULL; if (fdx) { FuncDeclaration *fd = fdx->overloadExactMatch(tfeqptr); if (!fd) { fd = fdx->overloadExactMatch(tfeq); if (fd) { // Create the thunk, fdptr FuncDeclaration *fdptr = new FuncDeclaration(loc, loc, fdx->ident, STCundefined, tfeqptr); Expression *e = new IdentifierExp(loc, Id::p); e = new PtrExp(loc, e); Expressions *args = new Expressions(); args->push(e); e = new IdentifierExp(loc, id); e = new CallExp(loc, e, args); fdptr->fbody = new ReturnStatement(loc, e); ScopeDsymbol *s = fdx->parent->isScopeDsymbol(); assert(s); s->members->push(fdptr); fdptr->addMember(sc, s, 1); fdptr->semantic(sc2); } } } id = Id::cmp; } #if V2 dtor = buildDtor(sc2); postblit = buildPostBlit(sc2); cpctor = buildCpCtor(sc2); buildOpAssign(sc2); #endif sc2->pop(); if (sizeok == 2) { // semantic() failed because of forward references. // Unwind what we did, and defer it for later fields.setDim(0); structsize = 0; alignsize = 0; structalign = 0; scope = scx ? scx : new Scope(*sc); scope->setNoFree(); scope->module->addDeferredSemantic(this); //printf("\tdeferring %s\n", toChars()); return; } // 0 sized struct's are set to 1 byte if (structsize == 0) { structsize = 1; alignsize = 1; } // Round struct size up to next alignsize boundary. // This will ensure that arrays of structs will get their internals // aligned properly. structsize = (structsize + alignsize - 1) & ~(alignsize - 1); sizeok = 1; Module::dprogress++; //printf("-StructDeclaration::semantic(this=%p, '%s')\n", this, toChars()); // Determine if struct is all zeros or not zeroInit = 1; for (i = 0; i < fields.dim; i++) { Dsymbol *s = (Dsymbol *)fields.data[i]; VarDeclaration *vd = s->isVarDeclaration(); if (vd && !vd->isDataseg()) { if (vd->init) { // Should examine init to see if it is really all 0's zeroInit = 0; break; } else { if (!vd->type->isZeroInit()) { zeroInit = 0; break; } } } } /* Look for special member functions. */ #if V2 ctor = (CtorDeclaration *)search(0, Id::ctor, 0); #endif inv = (InvariantDeclaration *)search(0, Id::classInvariant, 0); aggNew = (NewDeclaration *)search(0, Id::classNew, 0); aggDelete = (DeleteDeclaration *)search(0, Id::classDelete, 0); if (sc->func) { semantic2(sc); semantic3(sc); } } void StructDeclaration::toCBuffer(OutBuffer *buf, HdrGenState *hgs) { int i; buf->printf("%s ", kind()); if (!isAnonymous()) buf->writestring(toChars()); if (!members) { buf->writeByte(';'); buf->writenl(); return; } buf->writenl(); buf->writeByte('{'); buf->writenl(); for (i = 0; i < members->dim; i++) { Dsymbol *s = (Dsymbol *)members->data[i]; buf->writestring(" "); s->toCBuffer(buf, hgs); } buf->writeByte('}'); buf->writenl(); } const char *StructDeclaration::kind() { return "struct"; } /********************************* UnionDeclaration ****************************/ UnionDeclaration::UnionDeclaration(Loc loc, Identifier *id) : StructDeclaration(loc, id) { } Dsymbol *UnionDeclaration::syntaxCopy(Dsymbol *s) { UnionDeclaration *ud; if (s) ud = (UnionDeclaration *)s; else ud = new UnionDeclaration(loc, ident); StructDeclaration::syntaxCopy(ud); return ud; } const char *UnionDeclaration::kind() { return "union"; }