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552 lines
20 KiB
C++
552 lines
20 KiB
C++
//===-- nested.cpp --------------------------------------------------------===//
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//
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// LDC – the LLVM D compiler
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//
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// This file is distributed under the BSD-style LDC license. See the LICENSE
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// file for details.
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//
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//===----------------------------------------------------------------------===//
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#include "target.h"
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#include "gen/nested.h"
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#include "gen/dvalue.h"
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#include "gen/functions.h"
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#include "gen/irstate.h"
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#include "gen/llvmhelpers.h"
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#include "gen/logger.h"
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#include "gen/tollvm.h"
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#include "ir/irfunction.h"
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#include "ir/irtypeaggr.h"
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#include "llvm/Analysis/ValueTracking.h"
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/****************************************************************************************/
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/*////////////////////////////////////////////////////////////////////////////////////////
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// NESTED VARIABLE HELPERS
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////////////////////////////////////////////////////////////////////////////////////////*/
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static void storeVariable(VarDeclaration *vd, LLValue *dst)
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{
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LLValue *value = getIrLocal(vd)->value;
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int ty = vd->type->ty;
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FuncDeclaration *fd = getParentFunc(vd, true);
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assert(fd && "No parent function for nested variable?");
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if (fd->needsClosure() && !vd->isRef() && (ty == Tstruct || ty == Tsarray) && isaPointer(value->getType())) {
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// Copy structs and static arrays
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LLValue *mem = DtoGcMalloc(vd->loc, DtoType(vd->type), ".gc_mem");
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DtoAggrCopy(mem, value);
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DtoAlignedStore(mem, dst);
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} else
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// Store the address into the frame
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DtoAlignedStore(value, dst);
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}
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static unsigned getVthisIdx(AggregateDeclaration* ad)
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{
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return getFieldGEPIndex(ad, ad->vthis);
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}
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static void DtoCreateNestedContextType(FuncDeclaration* fd);
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DValue* DtoNestedVariable(Loc& loc, Type* astype, VarDeclaration* vd, bool byref)
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{
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IF_LOG Logger::println("DtoNestedVariable for %s @ %s", vd->toChars(), loc.toChars());
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LOG_SCOPE;
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////////////////////////////////////
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// Locate context value
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Dsymbol* vdparent = vd->toParent2();
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assert(vdparent);
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IrFunction* irfunc = gIR->func();
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// Check whether we can access the needed frame
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FuncDeclaration *fd = irfunc->decl;
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while (fd != vdparent) {
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if (fd->isStatic()) {
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error(loc, "function %s cannot access frame of function %s", irfunc->decl->toPrettyChars(), vdparent->toPrettyChars());
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return new DVarValue(astype, vd, llvm::UndefValue::get(DtoPtrToType(astype)));
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}
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fd = getParentFunc(fd, false);
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assert(fd);
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}
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// is the nested variable in this scope?
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if (vdparent == irfunc->decl)
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{
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LLValue* val = getIrValue(vd);
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return new DVarValue(astype, vd, val);
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}
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LLValue *dwarfValue = 0;
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#if LDC_LLVM_VER >= 306
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std::vector<int64_t> dwarfAddr;
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#else
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std::vector<LLValue*> dwarfAddr;
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#endif
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// get the nested context
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LLValue* ctx = 0;
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if (irfunc->nestedVar) {
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// If this function has its own nested context struct, always load it.
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ctx = irfunc->nestedVar;
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dwarfValue = ctx;
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} else if (irfunc->decl->isMember2()) {
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// If this is a member function of a nested class without its own
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// context, load the vthis member.
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AggregateDeclaration* cd = irfunc->decl->isMember2();
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LLValue* val = irfunc->thisArg;
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if (cd->isClassDeclaration())
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val = DtoLoad(val);
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ctx = DtoLoad(DtoGEPi(val, 0, getVthisIdx(cd), ".vthis"));
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} else {
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// Otherwise, this is a simple nested function, load from the context
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// argument.
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ctx = DtoLoad(irfunc->nestArg);
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dwarfValue = irfunc->nestArg;
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if (global.params.symdebug)
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gIR->DBuilder.OpDeref(dwarfAddr);
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}
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assert(ctx);
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DtoCreateNestedContextType(vdparent->isFuncDeclaration());
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assert(isIrLocalCreated(vd));
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////////////////////////////////////
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// Extract variable from nested context
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LLValue* val = DtoBitCast(ctx, LLPointerType::getUnqual(irfunc->frameType));
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IF_LOG {
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Logger::cout() << "Context: " << *val << '\n';
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Logger::cout() << "of type: " << *irfunc->frameType << '\n';
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}
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unsigned vardepth = getIrLocal(vd)->nestedDepth;
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unsigned funcdepth = irfunc->depth;
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IF_LOG {
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Logger::cout() << "Variable: " << vd->toChars() << '\n';
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Logger::cout() << "Variable depth: " << vardepth << '\n';
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Logger::cout() << "Function: " << irfunc->decl->toChars() << '\n';
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Logger::cout() << "Function depth: " << funcdepth << '\n';
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}
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if (vardepth == funcdepth) {
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// This is not always handled above because functions without
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// variables accessed by nested functions don't create new frames.
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IF_LOG Logger::println("Same depth");
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} else {
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// Load frame pointer and index that...
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if (dwarfValue && global.params.symdebug) {
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gIR->DBuilder.OpOffset(dwarfAddr, val, vardepth);
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gIR->DBuilder.OpDeref(dwarfAddr);
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}
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IF_LOG Logger::println("Lower depth");
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val = DtoGEPi(val, 0, vardepth);
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IF_LOG Logger::cout() << "Frame index: " << *val << '\n';
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val = DtoAlignedLoad(val, (std::string(".frame.") + vdparent->toChars()).c_str());
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IF_LOG Logger::cout() << "Frame: " << *val << '\n';
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}
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int idx = getIrLocal(vd)->nestedIndex;
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assert(idx != -1 && "Nested context not yet resolved for variable.");
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if (dwarfValue && global.params.symdebug)
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gIR->DBuilder.OpOffset(dwarfAddr, val, idx);
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val = DtoGEPi(val, 0, idx, vd->toChars());
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IF_LOG {
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Logger::cout() << "Addr: " << *val << '\n';
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Logger::cout() << "of type: " << *val->getType() << '\n';
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}
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if (byref || (vd->isParameter() && getIrParameter(vd)->arg && getIrParameter(vd)->arg->byref)) {
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val = DtoAlignedLoad(val);
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//dwarfOpDeref(dwarfAddr);
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IF_LOG {
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Logger::cout() << "Was byref, now: " << *val << '\n';
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Logger::cout() << "of type: " << *val->getType() << '\n';
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}
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}
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if (dwarfValue && global.params.symdebug)
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gIR->DBuilder.EmitLocalVariable(dwarfValue, vd, 0, false, dwarfAddr);
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return new DVarValue(astype, vd, val);
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}
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void DtoResolveNestedContext(Loc& loc, AggregateDeclaration *decl, LLValue *value)
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{
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IF_LOG Logger::println("Resolving nested context");
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LOG_SCOPE;
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// get context
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LLValue* nest = DtoNestedContext(loc, decl);
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// store into right location
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if (!llvm::dyn_cast<llvm::UndefValue>(nest)) {
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// Need to make sure the declaration has already been resolved, because
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// when multiple source files are specified on the command line, the
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// frontend sometimes adds "nested" (i.e. a template in module B
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// instantiated from module A with a type from module A instantiates
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// another template from module B) into the wrong module, messing up
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// our codegen order.
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DtoResolveDsymbol(decl);
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unsigned idx = getVthisIdx(decl);
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LLValue* gep = DtoGEPi(value,0,idx,".vthis");
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DtoStore(DtoBitCast(nest, gep->getType()->getContainedType(0)), gep);
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}
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}
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LLValue* DtoNestedContext(Loc& loc, Dsymbol* sym)
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{
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IF_LOG Logger::println("DtoNestedContext for %s", sym->toPrettyChars());
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LOG_SCOPE;
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// Exit quickly for functions that accept a context pointer for ABI purposes,
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// but do not actually read from it.
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//
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// We cannot simply fall back to retuning undef once we discover that we
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// don't actually have a context to pass, because we sadly also need to
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// catch invalid code here in the glue layer (see error() below).
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if (FuncDeclaration* symfd = sym->isFuncDeclaration())
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{
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// Make sure we've had a chance to analyze nested context usage
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DtoCreateNestedContextType(symfd);
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int depth = getIrFunc(symfd)->depth;
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Logger::println("for function of depth %d", depth);
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if (depth == -1 || (depth == 0 && !symfd->closureVars.empty()))
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{
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Logger::println("function does not have context or creates its own "
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"from scratch, returning undef");
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return llvm::UndefValue::get(getVoidPtrType());
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}
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}
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// The function we are currently in, and the constructed object/called
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// function might inherit a context pointer from.
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IrFunction* irfunc = gIR->func();
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bool fromParent = true;
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LLValue* val;
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if (irfunc->nestedVar)
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{
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// if this func has its own vars that are accessed by nested funcs
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// use its own context
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val = irfunc->nestedVar;
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fromParent = false;
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}
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else if (irfunc->nestArg)
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{
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// otherwise, it may have gotten a context from the caller
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val = DtoLoad(irfunc->nestArg);
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}
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else if (irfunc->thisArg)
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{
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// or just have a this argument
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AggregateDeclaration* ad = irfunc->decl->isMember2();
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val = ad->isClassDeclaration() ? DtoLoad(irfunc->thisArg) : irfunc->thisArg;
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if (!ad->vthis)
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{
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// This is just a plain 'outer' reference of a class nested in a
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// function (but without any variables in the nested context).
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return val;
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}
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val = DtoLoad(DtoGEPi(val, 0, getVthisIdx(ad), ".vthis"));
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}
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else
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{
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if (sym->isFuncDeclaration())
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{
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// If we are here, the function actually needs its nested context
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// and we cannot provide one. Thus, it's invalid code that is
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// unfortunately not caught in the frontend (e.g. a function literal
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// tries to call a nested function from the parent scope).
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error(loc, "function %s is a nested function and cannot be accessed from %s",
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sym->toPrettyChars(), irfunc->decl->toPrettyChars());
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fatal();
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}
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// Use null instead of e.g. LLVM's undef to not break bitwise
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// comparison for instances of nested struct types which don't have any
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// nested references.
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return llvm::ConstantPointerNull::get(getVoidPtrType());
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}
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FuncDeclaration* frameToPass = 0;
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if (AggregateDeclaration *ad = sym->isAggregateDeclaration()) {
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// If sym is a nested struct or a nested class, pass the frame
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// of the function where sym is declared.
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frameToPass = ad->toParent()->isFuncDeclaration();
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} else if (FuncDeclaration* symfd = sym->isFuncDeclaration()) {
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// If sym is a nested function, and its parent context is different
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// than the one we got, adjust it.
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frameToPass = getParentFunc(symfd, true);
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}
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if (frameToPass) {
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IF_LOG Logger::println("Parent frame is from %s", frameToPass->toChars());
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FuncDeclaration* ctxfd = irfunc->decl;
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IF_LOG Logger::println("Current function is %s", ctxfd->toChars());
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if (fromParent) {
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ctxfd = getParentFunc(ctxfd, true);
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assert(ctxfd && "Context from outer function, but no outer function?");
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}
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IF_LOG Logger::println("Context is from %s", ctxfd->toChars());
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unsigned neededDepth = getIrFunc(frameToPass)->depth;
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unsigned ctxDepth = getIrFunc(ctxfd)->depth;
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IF_LOG {
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Logger::cout() << "Needed depth: " << neededDepth << '\n';
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Logger::cout() << "Context depth: " << ctxDepth << '\n';
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}
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if (neededDepth >= ctxDepth) {
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// assert(neededDepth <= ctxDepth + 1 && "How are we going more than one nesting level up?");
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// fd needs the same context as we do, so all is well
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IF_LOG Logger::println("Calling sibling function or directly nested function");
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} else {
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val = DtoBitCast(val, LLPointerType::getUnqual(getIrFunc(ctxfd)->frameType));
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val = DtoGEPi(val, 0, neededDepth);
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val = DtoAlignedLoad(val,
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(std::string(".frame.") + frameToPass->toChars()).c_str());
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}
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}
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IF_LOG {
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Logger::cout() << "result = " << *val << '\n';
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Logger::cout() << "of type " << *val->getType() << '\n';
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}
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return val;
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}
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static void DtoCreateNestedContextType(FuncDeclaration* fd)
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{
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IF_LOG Logger::println("DtoCreateNestedContextType for %s", fd->toPrettyChars());
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LOG_SCOPE
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DtoDeclareFunction(fd);
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IrFunction& irFunc = *getIrFunc(fd);
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if (irFunc.nestedContextCreated)
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return;
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irFunc.nestedContextCreated = true;
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FuncDeclaration* parentFunc = getParentFunc(fd, true);
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// Make sure the parent has already been analyzed.
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if (parentFunc)
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DtoCreateNestedContextType(parentFunc);
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// construct nested variables array
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if (fd->closureVars.dim > 0)
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{
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Logger::println("has nested frame");
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// start with adding all enclosing parent frames until a static parent is reached
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LLStructType* innerFrameType = NULL;
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unsigned depth = 0;
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if (parentFunc)
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{
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IrFunction& parentIrFunc = *getIrFunc(parentFunc);
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innerFrameType = parentIrFunc.frameType;
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if (innerFrameType)
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depth = parentIrFunc.depth + 1;
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}
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irFunc.depth = depth;
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IF_LOG Logger::cout() << "Function " << fd->toChars() << " has depth " << depth << '\n';
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AggrTypeBuilder builder(false);
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if (depth != 0)
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{
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assert(innerFrameType);
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unsigned ptrSize = gDataLayout->getPointerSize();
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// Add frame pointer types for all but last frame
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for (unsigned i = 0; i < (depth - 1); ++i)
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builder.addType(innerFrameType->getElementType(i), ptrSize);
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// Add frame pointer type for last frame
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builder.addType(LLPointerType::getUnqual(innerFrameType), ptrSize);
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}
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// Add the direct nested variables of this function, and update their indices to match.
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// TODO: optimize ordering for minimal space usage?
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for (auto vd : fd->closureVars)
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{
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unsigned alignment = DtoAlignment(vd);
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if (alignment > 1)
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builder.alignCurrentOffset(alignment);
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IrLocal& irLocal = *getIrLocal(vd, true);
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irLocal.nestedIndex = builder.currentFieldIndex();
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irLocal.nestedDepth = depth;
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LLType* t = NULL;
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if (vd->isParameter() && getIrParameter(vd)->arg)
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{
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// Parameters that are part of the LLVM signature will have
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// storage associated with them (to handle byref etc.), so
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// handle those cases specially by storing a pointer instead
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// of a value.
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const IrParameter* irparam = getIrParameter(vd);
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const bool refout = vd->storage_class & (STCref | STCout);
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const bool lazy = vd->storage_class & STClazy;
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const bool byref = irparam->arg->byref;
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const bool isVthisPtr = irparam->isVthis && !byref;
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if (!(refout || (byref && !lazy)) || isVthisPtr)
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{
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// This will be copied to the nesting frame.
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if (lazy)
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t = irparam->value->getType()->getContainedType(0);
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else
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t = DtoMemType(vd->type);
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}
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else
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t = irparam->value->getType();
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}
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else if (isSpecialRefVar(vd))
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t = DtoType(vd->type->pointerTo());
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else
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t = DtoMemType(vd->type);
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builder.addType(t, getTypeAllocSize(t));
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IF_LOG Logger::cout() << "Nested var '" << vd->toChars()
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<< "' of type " << *t << "\n";
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}
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LLStructType* frameType = LLStructType::create(gIR->context(), builder.defaultTypes(),
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std::string("nest.") + fd->toChars());
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IF_LOG Logger::cout() << "frameType = " << *frameType << '\n';
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// Store type in IrFunction
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irFunc.frameType = frameType;
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irFunc.frameTypeAlignment = builder.overallAlignment();
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}
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else // no captured variables
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{
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if (parentFunc)
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{
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// Propagate context arg properties if the context arg is passed on unmodified.
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IrFunction& parentIrFunc = *getIrFunc(parentFunc);
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irFunc.frameType = parentIrFunc.frameType;
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irFunc.frameTypeAlignment = parentIrFunc.frameTypeAlignment;
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irFunc.depth = parentIrFunc.depth;
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}
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}
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}
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void DtoCreateNestedContext(FuncDeclaration* fd) {
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IF_LOG Logger::println("DtoCreateNestedContext for %s", fd->toPrettyChars());
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LOG_SCOPE
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DtoCreateNestedContextType(fd);
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// construct nested variables array
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if (fd->closureVars.dim > 0)
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{
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IrFunction* irfunction = getIrFunc(fd);
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unsigned depth = irfunction->depth;
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LLStructType *frameType = irfunction->frameType;
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// Create frame for current function and append to frames list
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LLValue* frame = 0;
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bool needsClosure = fd->needsClosure();
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if (needsClosure)
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{
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// FIXME: alignment ?
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frame = DtoGcMalloc(fd->loc, frameType, ".frame");
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}
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else
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{
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unsigned alignment = std::max(getABITypeAlign(frameType), irfunction->frameTypeAlignment);
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frame = DtoRawAlloca(frameType, alignment, ".frame");
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}
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// copy parent frames into beginning
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if (depth != 0) {
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LLValue* src = irfunction->nestArg;
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if (!src) {
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assert(irfunction->thisArg);
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assert(fd->isMember2());
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LLValue* thisval = DtoLoad(irfunction->thisArg);
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AggregateDeclaration* cd = fd->isMember2();
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assert(cd);
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assert(cd->vthis);
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Logger::println("Indexing to 'this'");
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if (cd->isStructDeclaration())
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src = DtoExtractValue(thisval, getVthisIdx(cd), ".vthis");
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else
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src = DtoLoad(DtoGEPi(thisval, 0, getVthisIdx(cd), ".vthis"));
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} else {
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src = DtoLoad(src);
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}
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if (depth > 1) {
|
||
src = DtoBitCast(src, getVoidPtrType());
|
||
LLValue* dst = DtoBitCast(frame, getVoidPtrType());
|
||
DtoMemCpy(dst, src, DtoConstSize_t((depth-1) * Target::ptrsize),
|
||
getABITypeAlign(getVoidPtrType()));
|
||
}
|
||
// Copy nestArg into framelist; the outer frame is not in the list of pointers
|
||
src = DtoBitCast(src, frameType->getContainedType(depth-1));
|
||
LLValue* gep = DtoGEPi(frame, 0, depth-1);
|
||
DtoAlignedStore(src, gep);
|
||
}
|
||
|
||
// store context in IrFunction
|
||
irfunction->nestedVar = frame;
|
||
|
||
// go through all nested vars and assign addresses where possible.
|
||
for (auto vd : fd->closureVars) {
|
||
if (needsClosure && vd->needsAutoDtor()) {
|
||
// This should really be a front-end, not a glue layer error,
|
||
// but we need to fix this in DMD too.
|
||
vd->error("has scoped destruction, cannot build closure");
|
||
}
|
||
|
||
IrLocal *irLocal = getIrLocal(vd);
|
||
LLValue* gep = DtoGEPi(frame, 0, irLocal->nestedIndex, vd->toChars());
|
||
if (vd->isParameter()) {
|
||
IF_LOG Logger::println("nested param: %s", vd->toChars());
|
||
LOG_SCOPE
|
||
IrParameter* parm = getIrParameter(vd);
|
||
|
||
if (parm->arg && parm->arg->byref)
|
||
{
|
||
storeVariable(vd, gep);
|
||
}
|
||
else
|
||
{
|
||
Logger::println("Copying to nested frame");
|
||
// The parameter value is an alloca'd stack slot.
|
||
// Copy to the nesting frame and leave the alloca for
|
||
// the optimizers to clean up.
|
||
DtoStore(DtoLoad(parm->value), gep);
|
||
gep->takeName(parm->value);
|
||
parm->value = gep;
|
||
}
|
||
} else {
|
||
IF_LOG Logger::println("nested var: %s", vd->toChars());
|
||
assert(!irLocal->value);
|
||
irLocal->value = gep;
|
||
}
|
||
|
||
if (global.params.symdebug) {
|
||
#if LDC_LLVM_VER >= 306
|
||
LLSmallVector<int64_t, 2> addr;
|
||
#else
|
||
LLSmallVector<LLValue*, 2> addr;
|
||
#endif
|
||
gIR->DBuilder.OpOffset(addr, frameType, irLocal->nestedIndex);
|
||
gIR->DBuilder.EmitLocalVariable(gep, vd, 0, false, addr);
|
||
}
|
||
}
|
||
}
|
||
}
|