Use Module::members -> Dsymbol::codegen to define symbols.

This commit fundamentally changes the way symbol emission in
LDC works: Previously, whenever a declaration was used in some
way, the compiler would check whether it actually needs to be
defined in the currently processed module, based only on the
symbol itself. This lack of contextual information proved to
be a major problem in correctly handling emission of templates
(see e.g. #454).

Now, the DtoResolve…() family of functions and similar only
ever declare the symbols, and definition is handled by doing
a single pass over Module::members for the root module. This
is the same strategy that DMD uses as well, which should
also reduce the maintainance burden down the road (which is
important as during the last few releases, there was pretty
much always a symbol emission related problem slowing us
down).

Our old approach might have been a bit better tuned w.r.t.
avoiding emission of unneeded template instances, but 2.064
will bring improvements here (DMD: FuncDeclaration::toObjFile).
Barring such issues, the change shoud also marginally improve
compile times because of declarations no longer being emitted
when they are not needed.

In the future, we should also consider refactoring the code
so that it no longer directly accesses Dsymbol::ir but uses
wrapper functions that ensure that the appropriate
DtoResolve…() function has been called.

GitHub: Fixes #454.
This commit is contained in:
David Nadlinger
2013-10-13 04:31:41 +02:00
parent b556ad9996
commit 787c147986
22 changed files with 439 additions and 517 deletions

View File

@@ -53,12 +53,10 @@ LLGlobalVariable * IrAggr::getVtblSymbol()
initname.append(aggrdecl->mangle());
initname.append("6__vtblZ");
llvm::GlobalValue::LinkageTypes _linkage = DtoExternalLinkage(aggrdecl);
LLType* vtblTy = stripModifiers(type)->irtype->isClass()->getVtbl();
vtbl = getOrCreateGlobal(aggrdecl->loc,
*gIR->module, vtblTy, true, _linkage, NULL, initname);
*gIR->module, vtblTy, true, llvm::GlobalValue::ExternalLinkage, NULL, initname);
return vtbl;
}
@@ -79,8 +77,9 @@ LLGlobalVariable * IrAggr::getClassInfoSymbol()
else
initname.append("7__ClassZ");
llvm::GlobalValue::LinkageTypes _linkage = DtoExternalLinkage(aggrdecl);
// The type is also ClassInfo for interfaces the actual TypeInfo for them
// is a TypeInfo_Interface instance that references __ClassZ in its "base"
// member.
ClassDeclaration* cinfo = ClassDeclaration::classinfo;
DtoType(cinfo->type);
IrTypeClass* tc = stripModifiers(cinfo->type)->irtype->isClass();
@@ -88,7 +87,8 @@ LLGlobalVariable * IrAggr::getClassInfoSymbol()
// classinfos cannot be constants since they're used as locks for synchronized
classInfo = getOrCreateGlobal(aggrdecl->loc,
*gIR->module, tc->getMemoryLLType(), false, _linkage, NULL, initname);
*gIR->module, tc->getMemoryLLType(), false,
llvm::GlobalValue::ExternalLinkage, NULL, initname);
// Generate some metadata on this ClassInfo if it's for a class.
ClassDeclaration* classdecl = aggrdecl->isClassDeclaration();
@@ -138,9 +138,8 @@ LLGlobalVariable * IrAggr::getInterfaceArraySymbol()
name.append(cd->mangle());
name.append("16__interfaceInfosZ");
llvm::GlobalValue::LinkageTypes _linkage = DtoExternalLinkage(aggrdecl);
classInterfacesArray = getOrCreateGlobal(cd->loc, *gIR->module,
array_type, true, _linkage, NULL, name);
array_type, true, llvm::GlobalValue::ExternalLinkage, NULL, name);
return classInterfacesArray;
}
@@ -182,7 +181,7 @@ LLConstant * IrAggr::getVtblInit()
}
else
{
fd->codegen(Type::sir);
DtoResolveFunction(fd);
assert(fd->ir.irFunc && "invalid vtbl function");
c = fd->ir.irFunc->func;
if (cd->isFuncHidden(fd))
@@ -320,7 +319,7 @@ llvm::GlobalVariable * IrAggr::getInterfaceVtbl(BaseClass * b, bool new_instance
assert((!fd->isAbstract() || fd->fbody) &&
"null symbol in interface implementation vtable");
fd->codegen(Type::sir);
DtoResolveFunction(fd);
assert(fd->ir.irFunc && "invalid vtbl function");
LLFunction *fn = fd->ir.irFunc->func;
@@ -380,9 +379,6 @@ llvm::GlobalVariable * IrAggr::getInterfaceVtbl(BaseClass * b, bool new_instance
// build the vtbl constant
llvm::Constant* vtbl_constant = LLConstantStruct::getAnon(gIR->context(), constants, false);
// create the global variable to hold it
llvm::GlobalValue::LinkageTypes _linkage = DtoExternalLinkage(aggrdecl);
std::string mangle("_D");
mangle.append(cd->mangle());
mangle.append("11__interface");
@@ -393,7 +389,7 @@ llvm::GlobalVariable * IrAggr::getInterfaceVtbl(BaseClass * b, bool new_instance
*gIR->module,
vtbl_constant->getType(),
true,
_linkage,
llvm::GlobalValue::ExternalLinkage,
vtbl_constant,
mangle
);