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//===-- objcgen.cpp -------------------------------------------------------===//
//
// LDC – the LLVM D compiler
//
// This file is distributed under the BSD-style LDC license. See the LICENSE
// file for details.
//
// Support limited to Objective-C on Darwin (OS X, iOS, tvOS, watchOS)
//
//===----------------------------------------------------------------------===//
#include "gen/objcgen.h"
#include "dmd/mtype.h"
#include "dmd/objc.h"
#include "gen/irstate.h"
namespace {
enum ABI { none = 0, fragile = 1, nonFragile = 2 };
ABI abi = nonFragile;
}
bool objc_isSupported(const llvm::Triple &triple) {
if (triple.isOSDarwin()) {
// Objective-C only supported on Darwin at this time
switch (triple.getArch()) {
case llvm::Triple::aarch64: // arm64 iOS, tvOS
case llvm::Triple::arm: // armv6 iOS
case llvm::Triple::thumb: // thumbv7 iOS, watchOS
case llvm::Triple::x86_64: // OSX, iOS, tvOS sim
abi = nonFragile;
return true;
case llvm::Triple::x86: // OSX, iOS, watchOS sim
abi = fragile;
return true;
default:
break;
}
}
return false;
}
LLGlobalVariable *ObjCState::getCStringVar(const char *symbol,
const llvm::StringRef &str,
const char *section) {
auto init = llvm::ConstantDataArray::getString(module.getContext(), str);
auto var = new LLGlobalVariable(module, init->getType(), false,
LLGlobalValue::PrivateLinkage, init, symbol);
var->setSection(section);
return var;
}
LLGlobalVariable *ObjCState::getMethVarName(const llvm::StringRef &name) {
auto it = methVarNameMap.find(name);
if (it != methVarNameMap.end()) {
return it->second;
}
auto var = getCStringVar("OBJC_METH_VAR_NAME_", name,
abi == nonFragile
? "__TEXT,__objc_methname,cstring_literals"
: "__TEXT,__cstring,cstring_literals");
methVarNameMap[name] = var;
retain(var);
return var;
}
LLGlobalVariable *ObjCState::getMethVarRef(const ObjcSelector &sel) {
llvm::StringRef s(sel.stringvalue, sel.stringlen);
auto it = methVarRefMap.find(s);
if (it != methVarRefMap.end()) {
return it->second;
}
auto gvar = getMethVarName(s);
auto selref = new LLGlobalVariable(
module, gvar->getType(),
false, // prevent const elimination optimization
LLGlobalValue::PrivateLinkage, gvar, "OBJC_SELECTOR_REFERENCES_", nullptr,
LLGlobalVariable::NotThreadLocal, 0,
true); // externally initialized
selref->setSection(
abi == nonFragile
? "__DATA,__objc_selrefs,literal_pointers,no_dead_strip"
: "__OBJC,__message_refs,literal_pointers,no_dead_strip");
// Save for later lookup and prevent optimizer elimination
methVarRefMap[s] = selref;
retain(selref);
return selref;
}
void ObjCState::retain(LLConstant *sym) {
retainedSymbols.push_back(DtoBitCast(sym, getVoidPtrType()));
}
void ObjCState::finalize() {
if (!retainedSymbols.empty()) {
genImageInfo();
// add in references so optimizer won't remove symbols.
retainSymbols();
}
}
void ObjCState::genImageInfo() {
// Use LLVM to generate image info
const char *section =
(abi == nonFragile ? "__DATA,__objc_imageinfo,regular,no_dead_strip"
: "__OBJC,__image_info");
module.addModuleFlag(llvm::Module::Error, "Objective-C Version",
abi); // unused?
module.addModuleFlag(llvm::Module::Error, "Objective-C Image Info Version",
0u); // version
module.addModuleFlag(llvm::Module::Error, "Objective-C Image Info Section",
llvm::MDString::get(module.getContext(), section));
module.addModuleFlag(llvm::Module::Override, "Objective-C Garbage Collection",
0u); // flags
}
void ObjCState::retainSymbols() {
// put all objc symbols in the llvm.compiler.used array so optimizer won't
// remove.
auto arrayType = LLArrayType::get(retainedSymbols.front()->getType(),
retainedSymbols.size());
auto usedArray = LLConstantArray::get(arrayType, retainedSymbols);
auto var = new LLGlobalVariable(module, arrayType, false,
LLGlobalValue::AppendingLinkage, usedArray,
"llvm.compiler.used");
var->setSection("llvm.metadata");
}
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