[apple/ld64.git] / src / ld / passes / stubs / stubs.cpp

/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
 *
 * Copyright (c) 2009-2010 Apple Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_LICENSE_HEADER_END@
 */


#include <stdint.h>
#include <math.h>
#include <unistd.h>
#include <assert.h>
#include <libkern/OSByteOrder.h>

#include <vector>
#include <set>
#include <map>

#include "Options.h"
#include "ld.hpp"

#include "make_stubs.h"


namespace ld {
namespace passes {
namespace stubs {

class Pass {
public:
								Pass(const Options& opts);
	void						process(ld::Internal& internal);
	void						addAtom(const ld::Atom& atom)	{ _internal->addAtom(atom); }
	bool						usingCompressedLINKEDIT() const { return _compressedLINKEDIT; }
	ld::Internal*				internal() { return _internal; }

	Atom*						compressedHelperHelper;
	Atom*						compressedImageCache;
	Atom*						compressedFastBinderPointer;

private:

	struct AtomByNameSorter
	{
		 bool operator()(const ld::Atom* left, const ld::Atom* right)
		 {
			  return (strcmp(left->name(), right->name()) < 0);
		 }
	};

	const ld::Atom*				stubableFixup(const ld::Fixup* fixup, ld::Internal&);
	ld::Atom*					makeStub(const ld::Atom& target, bool weakImport);
	void						verifyNoResolverFunctions(ld::Internal& state);

	const Options&				_options;
	const cpu_type_t			_architecture;
	const bool					_lazyDylibsInUuse;
	const bool					_compressedLINKEDIT;
	const bool					_prebind;
	const bool					_mightBeInSharedRegion;
	const bool					_pic;
	const bool					_flatNamespace;
	ld::Internal*				_internal;
	uint32_t					_stubCount;
	bool						_largeText;
};

#include "stub_x86_64.hpp"
#include "stub_x86_64_classic.hpp"
#include "stub_x86.hpp"
#include "stub_x86_classic.hpp"
#include "stub_arm.hpp"
#include "stub_arm_classic.hpp"


Pass::Pass(const Options& opts) 
	:	compressedHelperHelper(NULL), 
		compressedImageCache(NULL),
		compressedFastBinderPointer(NULL),
		_options(opts),
		_architecture(opts.architecture()),
		_lazyDylibsInUuse(opts.usingLazyDylibLinking()),
		_compressedLINKEDIT(opts.makeCompressedDyldInfo()),
		_prebind(opts.prebind()),
		_mightBeInSharedRegion(opts.sharedRegionEligible()), 
		_pic(opts.outputSlidable()),
		_flatNamespace(opts.nameSpace() != Options::kTwoLevelNameSpace),
		_internal(NULL), _stubCount(0), _largeText(false)
{
	
} 


const ld::Atom* Pass::stubableFixup(const ld::Fixup* fixup, ld::Internal& state)
{
	if ( fixup->binding == ld::Fixup::bindingsIndirectlyBound ) {
		const ld::Atom* target = state.indirectBindingTable[fixup->u.bindingIndex];
		switch ( fixup->kind ) {
			case ld::Fixup::kindStoreTargetAddressX86BranchPCRel32:
			case ld::Fixup::kindStoreTargetAddressARMBranch24:
			case ld::Fixup::kindStoreTargetAddressThumbBranch22:
				// create stub if target is in a dylib
				if ( target->definition() == ld::Atom::definitionProxy ) 
					return target;
				// use stub if target is a resolver function in same linkage unit
				if ( target->contentType() == ld::Atom::typeResolver ) 
					return target;
				if ( target->scope() == ld::Atom::scopeGlobal ) {	
					// create stub if target is global weak definition in symbol table
					if ( (target->definition() == ld::Atom::definitionRegular) 
						&& (target->combine() == ld::Atom::combineByName) 
						&& ((target->symbolTableInclusion() == ld::Atom::symbolTableIn) 
						 || (target->symbolTableInclusion() == ld::Atom::symbolTableInAndNeverStrip)) )
						return target;
					// create stub if target is interposable
					if ( _options.interposable(target->name()) ) 
						return target;
					if ( _flatNamespace ) {
						// flat namespace does not indirect calls within main exectuables
						if ( _options.outputKind() == Options::kDynamicExecutable ) 
							return NULL;
						// create stub if target is global and building -flat dylib or bundle
						return target;
					}
				}
				break;
			default:
				if ( target->contentType() == ld::Atom::typeResolver ) {
					// any pointer to a resolver needs to change to pointer to stub
					return target;
				}
				break;
		}
	}
	return NULL;
}


ld::Atom* Pass::makeStub(const ld::Atom& target, bool weakImport)
{
	//fprintf(stderr, "makeStub(target=%p %s in sect %s)\n", &target, target.name(), target.section().sectionName());
	bool stubToGlobalWeakDef = ( (target.scope() == ld::Atom::scopeGlobal)
								&& (target.definition() == ld::Atom::definitionRegular) 
								&& (target.combine() == ld::Atom::combineByName) );

	bool forLazyDylib = false;
	const ld::dylib::File* dylib = dynamic_cast<const ld::dylib::File*>(target.file());
	if ( (dylib != NULL) && dylib->willBeLazyLoadedDylib() ) 
		forLazyDylib = true;
	bool stubToResolver = (target.contentType() == ld::Atom::typeResolver);
	
	if ( usingCompressedLINKEDIT() && !forLazyDylib ) {
		if ( _internal->compressedFastBinderProxy == NULL )
			throwf("symbol dyld_stub_binder not found (normally in libSystem.dylib).  Needed to perform lazy binding to function %s", target.name());
	}

	switch ( _architecture ) {
		case CPU_TYPE_I386:
			if ( usingCompressedLINKEDIT() && !forLazyDylib )
				return new ld::passes::stubs::x86::StubAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
			else
				return new ld::passes::stubs::x86::classic::StubAtom(*this, target, forLazyDylib, weakImport);
			break;
		case CPU_TYPE_X86_64:
			if ( usingCompressedLINKEDIT() && !forLazyDylib )
				return new ld::passes::stubs::x86_64::StubAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
			else
				return new ld::passes::stubs::x86_64::classic::StubAtom(*this, target, forLazyDylib, weakImport);
			break;
		case CPU_TYPE_ARM: 
			if ( usingCompressedLINKEDIT() && !forLazyDylib ) {
				if ( (_stubCount < 900) && !_mightBeInSharedRegion && !_largeText )
					return new ld::passes::stubs::arm::StubCloseAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
				else if ( _pic )
					return new ld::passes::stubs::arm::StubPICAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
				else
					return new ld::passes::stubs::arm::StubNoPICAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
			} 
			else {
				if ( _pic )
					return new ld::passes::stubs::arm::classic::StubPICAtom(*this, target, forLazyDylib, weakImport);
				else
					return new ld::passes::stubs::arm::classic::StubNoPICAtom(*this, target, forLazyDylib, weakImport);
			}
			break;
	}
	throw "unsupported arch for stub";
}


void Pass::verifyNoResolverFunctions(ld::Internal& state)
{
	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
		ld::Internal::FinalSection* sect = *sit;
		for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin();  ait != sect->atoms.end(); ++ait) {
			const ld::Atom* atom = *ait;
			if ( atom->contentType() == ld::Atom::typeResolver ) 
				throwf("resolver function '%s' not supported in type of output", atom->name());
		}
	}
}

void Pass::process(ld::Internal& state)
{
	switch ( _options.outputKind() ) {
		case Options::kObjectFile:
			// these kinds don't use stubs and can have resolver functions
			return;
		case Options::kKextBundle:
		case Options::kStaticExecutable:
		case Options::kPreload:
		case Options::kDyld:
			// these kinds don't use stubs and cannot have resolver functions
			verifyNoResolverFunctions(state);
			return;
		case Options::kDynamicLibrary:
			// uses stubs and can have resolver functions
			break;
		case Options::kDynamicExecutable:
		case Options::kDynamicBundle:
			// these kinds do use stubs and cannot have resolver functions
			verifyNoResolverFunctions(state);
			break;
	}
	
	// walk all atoms and fixups looking for stubable references
	// don't create stubs inline because that could invalidate the sections iterator
	std::vector<const ld::Atom*> atomsCallingStubs;
	std::map<const ld::Atom*,ld::Atom*> stubFor;
	std::map<const ld::Atom*,bool>		weakImportMap;
	atomsCallingStubs.reserve(128);
	uint64_t codeSize = 0;
	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
		ld::Internal::FinalSection* sect = *sit;
		for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin();  ait != sect->atoms.end(); ++ait) {
			const ld::Atom* atom = *ait;
			codeSize += atom->size();
			bool atomNeedsStub = false;
			for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
				const ld::Atom* stubableTargetOfFixup = stubableFixup(fit, state);
				if ( stubableTargetOfFixup != NULL ) {
					if ( !atomNeedsStub ) {
						atomsCallingStubs.push_back(atom);
						atomNeedsStub = true;
					}
					stubFor[stubableTargetOfFixup] = NULL;	
					// record weak_import attribute
					std::map<const ld::Atom*,bool>::iterator pos = weakImportMap.find(stubableTargetOfFixup);
					if ( pos == weakImportMap.end() ) {
						// target not in weakImportMap, so add
						weakImportMap[stubableTargetOfFixup] = fit->weakImport;
					}
					else {
						// target in weakImportMap, check for weakness mismatch
						if ( pos->second != fit->weakImport ) {
							// found mismatch
							switch ( _options.weakReferenceMismatchTreatment() ) {
								case Options::kWeakReferenceMismatchError:
									throwf("mismatching weak references for symbol: %s", stubableTargetOfFixup->name());
								case Options::kWeakReferenceMismatchWeak:
									pos->second = true;
									break;
								case Options::kWeakReferenceMismatchNonWeak:
									pos->second = false;
									break;
							}
						}
					}
				}
			}
			// all resolver functions must have a corresponding stub
			if ( atom->contentType() == ld::Atom::typeResolver ) {
				if ( _options.outputKind() != Options::kDynamicLibrary ) 
					throwf("resolver functions (%s) can only be used in dylibs", atom->name());
				if ( !_options.makeCompressedDyldInfo() ) {
					if ( _options.architecture() == CPU_TYPE_ARM )
						throwf("resolver functions (%s) can only be used when targeting iOS 4.2 or later", atom->name());
					else
						throwf("resolver functions (%s) can only be used when targeting Mac OS X 10.6 or later", atom->name());
				}
				stubFor[atom] = NULL;	
			}
		}
	}
	
	// short circuit if no stubs needed
	_internal = &state;
	_stubCount = stubFor.size();
	if ( _stubCount == 0 )
		return;
	
	// <rdar://problem/8553283> lazily check for helper
	if ( !_options.makeCompressedDyldInfo() && (state.classicBindingHelper == NULL) ) 
		throw "symbol dyld_stub_binding_helper not found, normally in crt1.o/dylib1.o/bundle1.o";

	// disable arm close stubs in some cases
	if ( _architecture == CPU_TYPE_ARM ) {
        if ( codeSize > 4*1024*1024 )
            _largeText = true;
        else {
            for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
                ld::Internal::FinalSection* sect = *sit;
                if ( sect->type() == ld::Section::typeMachHeader )
                    continue;
                if ( strcmp(sect->segmentName(), "__TEXT") == 0) {
                    for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin();  ait != sect->atoms.end(); ++ait) {
                        const ld::Atom* atom = *ait;
                        if ( atom->alignment().powerOf2 > 10 ) {
                            // overaligned section means might not be able to keep closestubs sect pushed to end of __TEXT
                            //warning("alignment 1<<%d in atom %s in section %s disables close stubs optimization", 
                            //        atom->alignment().powerOf2, atom->name(), sect->segmentName());
                            _largeText = true;
                            break;
                        }
                    }
                }
            }
        }
    }
	
	// make stub atoms 
	for (std::map<const ld::Atom*,ld::Atom*>::iterator it = stubFor.begin(); it != stubFor.end(); ++it) {
		it->second = makeStub(*it->first, weakImportMap[it->first]);
	}
	
	// updated atoms to use stubs
	for (std::vector<const ld::Atom*>::iterator it=atomsCallingStubs.begin(); it != atomsCallingStubs.end(); ++it) {
		const ld::Atom* atom = *it;
		for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
			const ld::Atom* stubableTargetOfFixup = stubableFixup(fit, state);
			if ( stubableTargetOfFixup != NULL ) {
				ld::Atom* stub = stubFor[stubableTargetOfFixup];
				assert(stub != NULL && "stub not created");
				fit->binding = ld::Fixup::bindingDirectlyBound;
				fit->u.target = stub;
			}
		}
	}
	
	// sort new atoms so links are consistent
	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
		ld::Internal::FinalSection* sect = *sit;
		switch ( sect->type() ) {
			case ld::Section::typeStubHelper:
			case ld::Section::typeStub:
			case ld::Section::typeStubClose:
			case ld::Section::typeLazyPointer:
			case ld::Section::typeLazyPointerClose:
				std::sort(sect->atoms.begin(), sect->atoms.end(), AtomByNameSorter());
				break;
			default:
				break;
		}
	}

}


void doPass(const Options& opts, ld::Internal& internal)
{
	Pass  pass(opts);
	pass.process(internal);
}


} // namespace stubs 
} // namespace passes 
} // namespace ld
Commit	Line	Data
a645023d A	1	/* -- mode: C++; c-basic-offset: 4; tab-width: 4 --
	2	*
	3	* Copyright (c) 2009-2010 Apple Inc. All rights reserved.
	4	*
	5	* @APPLE_LICENSE_HEADER_START@
	6	*
	7	* This file contains Original Code and/or Modifications of Original Code
	8	* as defined in and that are subject to the Apple Public Source License
	9	* Version 2.0 (the 'License'). You may not use this file except in
	10	* compliance with the License. Please obtain a copy of the License at
	11	* http://www.opensource.apple.com/apsl/ and read it before using this
	12	* file.
	13	*
	14	* The Original Code and all software distributed under the License are
	15	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	16	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	17	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	18	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	19	* Please see the License for the specific language governing rights and
	20	* limitations under the License.
	21	*
	22	* @APPLE_LICENSE_HEADER_END@
	23	*/
	24
	25
	26
	27	#include <stdint.h>
	28	#include <math.h>
	29	#include <unistd.h>
	30	#include <assert.h>
	31	#include <libkern/OSByteOrder.h>
	32
	33	#include <vector>
	34	#include <set>
	35	#include <map>
	36
	37	#include "Options.h"
	38	#include "ld.hpp"
	39
	40	#include "make_stubs.h"
	41
	42
	43	namespace ld {
	44	namespace passes {
	45	namespace stubs {
	46
	47	class Pass {
	48	public:
	49	Pass(const Options& opts);
	50	void process(ld::Internal& internal);
	51	void addAtom(const ld::Atom& atom) { _internal->addAtom(atom); }
	52	bool usingCompressedLINKEDIT() const { return _compressedLINKEDIT; }
	53	ld::Internal* internal() { return _internal; }
	54
	55	Atom* compressedHelperHelper;
	56	Atom* compressedImageCache;
	57	Atom* compressedFastBinderPointer;
	58
	59	private:
	60
	61	struct AtomByNameSorter
	62	{
	63	bool operator()(const ld::Atom* left, const ld::Atom* right)
	64	{
65	return (strcmp(left->name(), right->name()) < 0);
66	}
67	};
68
69	const ld::Atom* stubableFixup(const ld::Fixup* fixup, ld::Internal&);
70	ld::Atom* makeStub(const ld::Atom& target, bool weakImport);
71	void verifyNoResolverFunctions(ld::Internal& state);
72
73	const Options& _options;
74	const cpu_type_t _architecture;
75	const bool _lazyDylibsInUuse;
76	const bool _compressedLINKEDIT;
77	const bool _prebind;
78	const bool _mightBeInSharedRegion;
79	const bool _pic;
80	const bool _flatNamespace;
81	ld::Internal* _internal;
82	uint32_t _stubCount;
83	bool _largeText;
84	};
85
86	#include "stub_x86_64.hpp"
87	#include "stub_x86_64_classic.hpp"
88	#include "stub_x86.hpp"
89	#include "stub_x86_classic.hpp"
90	#include "stub_arm.hpp"
91	#include "stub_arm_classic.hpp"
a645023d A	92
	93
	94
	95	Pass::Pass(const Options& opts)
	96	: compressedHelperHelper(NULL),
	97	compressedImageCache(NULL),
	98	compressedFastBinderPointer(NULL),
	99	_options(opts),
	100	_architecture(opts.architecture()),
	101	_lazyDylibsInUuse(opts.usingLazyDylibLinking()),
	102	_compressedLINKEDIT(opts.makeCompressedDyldInfo()),
	103	_prebind(opts.prebind()),
	104	_mightBeInSharedRegion(opts.sharedRegionEligible()),
	105	_pic(opts.outputSlidable()),
	106	_flatNamespace(opts.nameSpace() != Options::kTwoLevelNameSpace),
	107	_internal(NULL), _stubCount(0), _largeText(false)
	108	{
	109
	110	}
	111
	112
	113	const ld::Atom* Pass::stubableFixup(const ld::Fixup* fixup, ld::Internal& state)
	114	{
	115	if ( fixup->binding == ld::Fixup::bindingsIndirectlyBound ) {
	116	const ld::Atom* target = state.indirectBindingTable[fixup->u.bindingIndex];
	117	switch ( fixup->kind ) {
a645023d A	118	case ld::Fixup::kindStoreTargetAddressX86BranchPCRel32:
	119	case ld::Fixup::kindStoreTargetAddressARMBranch24:
	120	case ld::Fixup::kindStoreTargetAddressThumbBranch22:
	121	// create stub if target is in a dylib
	122	if ( target->definition() == ld::Atom::definitionProxy )
	123	return target;
	124	// use stub if target is a resolver function in same linkage unit
	125	if ( target->contentType() == ld::Atom::typeResolver )
	126	return target;
	127	if ( target->scope() == ld::Atom::scopeGlobal ) {
	128	// create stub if target is global weak definition in symbol table
	129	if ( (target->definition() == ld::Atom::definitionRegular)
	130	&& (target->combine() == ld::Atom::combineByName)
	131	&& ((target->symbolTableInclusion() == ld::Atom::symbolTableIn)
	132	\|\| (target->symbolTableInclusion() == ld::Atom::symbolTableInAndNeverStrip)) )
	133	return target;
	134	// create stub if target is interposable
	135	if ( _options.interposable(target->name()) )
	136	return target;
	137	if ( _flatNamespace ) {
	138	// flat namespace does not indirect calls within main exectuables
	139	if ( _options.outputKind() == Options::kDynamicExecutable )
	140	return NULL;
	141	// create stub if target is global and building -flat dylib or bundle
	142	return target;
	143	}
	144	}
	145	break;
	146	default:
	147	if ( target->contentType() == ld::Atom::typeResolver ) {
	148	// any pointer to a resolver needs to change to pointer to stub
	149	return target;
	150	}
	151	break;
	152	}
	153	}
	154	return NULL;
	155	}
	156
	157
	158
	159	ld::Atom* Pass::makeStub(const ld::Atom& target, bool weakImport)
	160	{
	161	//fprintf(stderr, "makeStub(target=%p %s in sect %s)\n", &target, target.name(), target.section().sectionName());
	162	bool stubToGlobalWeakDef = ( (target.scope() == ld::Atom::scopeGlobal)
	163	&& (target.definition() == ld::Atom::definitionRegular)
	164	&& (target.combine() == ld::Atom::combineByName) );
	165
	166	bool forLazyDylib = false;
	167	const ld::dylib::File* dylib = dynamic_cast<const ld::dylib::File*>(target.file());
	168	if ( (dylib != NULL) && dylib->willBeLazyLoadedDylib() )
	169	forLazyDylib = true;
	170	bool stubToResolver = (target.contentType() == ld::Atom::typeResolver);
	171
afe874b1 A	172	if ( usingCompressedLINKEDIT() && !forLazyDylib ) {
	173	if ( _internal->compressedFastBinderProxy == NULL )
	174	throwf("symbol dyld_stub_binder not found (normally in libSystem.dylib). Needed to perform lazy binding to function %s", target.name());
	175	}
	176
a645023d	177	switch ( _architecture ) {
a645023d A	178	case CPU_TYPE_I386:
	179	if ( usingCompressedLINKEDIT() && !forLazyDylib )
	180	return new ld::passes::stubs::x86::StubAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
	181	else
	182	return new ld::passes::stubs::x86::classic::StubAtom(*this, target, forLazyDylib, weakImport);
	183	break;
	184	case CPU_TYPE_X86_64:
	185	if ( usingCompressedLINKEDIT() && !forLazyDylib )
	186	return new ld::passes::stubs::x86_64::StubAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
	187	else
	188	return new ld::passes::stubs::x86_64::classic::StubAtom(*this, target, forLazyDylib, weakImport);
	189	break;
	190	case CPU_TYPE_ARM:
	191	if ( usingCompressedLINKEDIT() && !forLazyDylib ) {
	192	if ( (_stubCount < 900) && !_mightBeInSharedRegion && !_largeText )
	193	return new ld::passes::stubs::arm::StubCloseAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
	194	else if ( _pic )
	195	return new ld::passes::stubs::arm::StubPICAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
	196	else
	197	return new ld::passes::stubs::arm::StubNoPICAtom(*this, target, stubToGlobalWeakDef, stubToResolver, weakImport);
	198	}
	199	else {
	200	if ( _pic )
	201	return new ld::passes::stubs::arm::classic::StubPICAtom(*this, target, forLazyDylib, weakImport);
	202	else
	203	return new ld::passes::stubs::arm::classic::StubNoPICAtom(*this, target, forLazyDylib, weakImport);
	204	}
	205	break;
	206	}
	207	throw "unsupported arch for stub";
	208	}
	209
	210
	211	void Pass::verifyNoResolverFunctions(ld::Internal& state)
	212	{
	213	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
	214	ld::Internal::FinalSection* sect = *sit;
	215	for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin(); ait != sect->atoms.end(); ++ait) {
	216	const ld::Atom* atom = *ait;
	217	if ( atom->contentType() == ld::Atom::typeResolver )
	218	throwf("resolver function '%s' not supported in type of output", atom->name());
	219	}
	220	}
	221	}
	222
	223	void Pass::process(ld::Internal& state)
	224	{
	225	switch ( _options.outputKind() ) {
	226	case Options::kObjectFile:
	227	// these kinds don't use stubs and can have resolver functions
	228	return;
	229	case Options::kKextBundle:
	230	case Options::kStaticExecutable:
	231	case Options::kPreload:
	232	case Options::kDyld:
	233	// these kinds don't use stubs and cannot have resolver functions
	234	verifyNoResolverFunctions(state);
	235	return;
	236	case Options::kDynamicLibrary:
	237	// uses stubs and can have resolver functions
	238	break;
	239	case Options::kDynamicExecutable:
	240	case Options::kDynamicBundle:
	241	// these kinds do use stubs and cannot have resolver functions
242	verifyNoResolverFunctions(state);
243	break;
244	}
245
246	// walk all atoms and fixups looking for stubable references
247	// don't create stubs inline because that could invalidate the sections iterator
248	std::vector<const ld::Atom*> atomsCallingStubs;
249	std::map<const ld::Atom,ld::Atom> stubFor;
250	std::map<const ld::Atom*,bool> weakImportMap;
251	atomsCallingStubs.reserve(128);
252	uint64_t codeSize = 0;
253	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
254	ld::Internal::FinalSection* sect = *sit;
255	for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin(); ait != sect->atoms.end(); ++ait) {
256	const ld::Atom* atom = *ait;
257	codeSize += atom->size();
258	bool atomNeedsStub = false;
259	for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
260	const ld::Atom* stubableTargetOfFixup = stubableFixup(fit, state);
261	if ( stubableTargetOfFixup != NULL ) {
262	if ( !atomNeedsStub ) {
263	atomsCallingStubs.push_back(atom);
264	atomNeedsStub = true;
265	}
266	stubFor[stubableTargetOfFixup] = NULL;
267	// record weak_import attribute
268	std::map<const ld::Atom*,bool>::iterator pos = weakImportMap.find(stubableTargetOfFixup);
269	if ( pos == weakImportMap.end() ) {
270	// target not in weakImportMap, so add
271	weakImportMap[stubableTargetOfFixup] = fit->weakImport;
a645023d A	272	}
	273	else {
	274	// target in weakImportMap, check for weakness mismatch
	275	if ( pos->second != fit->weakImport ) {
	276	// found mismatch
	277	switch ( _options.weakReferenceMismatchTreatment() ) {
	278	case Options::kWeakReferenceMismatchError:
	279	throwf("mismatching weak references for symbol: %s", stubableTargetOfFixup->name());
	280	case Options::kWeakReferenceMismatchWeak:
	281	pos->second = true;
	282	break;
	283	case Options::kWeakReferenceMismatchNonWeak:
	284	pos->second = false;
	285	break;
	286	}
	287	}
	288	}
	289	}
	290	}
	291	// all resolver functions must have a corresponding stub
	292	if ( atom->contentType() == ld::Atom::typeResolver ) {
	293	if ( _options.outputKind() != Options::kDynamicLibrary )
	294	throwf("resolver functions (%s) can only be used in dylibs", atom->name());
	295	if ( !_options.makeCompressedDyldInfo() ) {
b2fa67a8	296	if ( _options.architecture() == CPU_TYPE_ARM )
a645023d A	297	throwf("resolver functions (%s) can only be used when targeting iOS 4.2 or later", atom->name());
	298	else
	299	throwf("resolver functions (%s) can only be used when targeting Mac OS X 10.6 or later", atom->name());
	300	}
	301	stubFor[atom] = NULL;
	302	}
	303	}
	304	}
	305
	306	// short circuit if no stubs needed
	307	_internal = &state;
	308	_stubCount = stubFor.size();
	309	if ( _stubCount == 0 )
	310	return;
	311
	312	// <rdar://problem/8553283> lazily check for helper
	313	if ( !_options.makeCompressedDyldInfo() && (state.classicBindingHelper == NULL) )
	314	throw "symbol dyld_stub_binding_helper not found, normally in crt1.o/dylib1.o/bundle1.o";
	315
afe874b1 A	316	// disable arm close stubs in some cases
	317	if ( _architecture == CPU_TYPE_ARM ) {
	318	if ( codeSize > 410241024 )
	319	_largeText = true;
	320	else {
	321	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
	322	ld::Internal::FinalSection* sect = *sit;
	323	if ( sect->type() == ld::Section::typeMachHeader )
	324	continue;
	325	if ( strcmp(sect->segmentName(), "__TEXT") == 0) {
	326	for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin(); ait != sect->atoms.end(); ++ait) {
	327	const ld::Atom* atom = *ait;
	328	if ( atom->alignment().powerOf2 > 10 ) {
	329	// overaligned section means might not be able to keep closestubs sect pushed to end of __TEXT
	330	//warning("alignment 1<<%d in atom %s in section %s disables close stubs optimization",
	331	// atom->alignment().powerOf2, atom->name(), sect->segmentName());
	332	_largeText = true;
	333	break;
	334	}
	335	}
	336	}
	337	}
	338	}
	339	}
a645023d A	340
	341	// make stub atoms
	342	for (std::map<const ld::Atom,ld::Atom>::iterator it = stubFor.begin(); it != stubFor.end(); ++it) {
	343	it->second = makeStub(*it->first, weakImportMap[it->first]);
	344	}
	345
	346	// updated atoms to use stubs
	347	for (std::vector<const ld::Atom*>::iterator it=atomsCallingStubs.begin(); it != atomsCallingStubs.end(); ++it) {
	348	const ld::Atom* atom = *it;
	349	for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
	350	const ld::Atom* stubableTargetOfFixup = stubableFixup(fit, state);
	351	if ( stubableTargetOfFixup != NULL ) {
	352	ld::Atom* stub = stubFor[stubableTargetOfFixup];
	353	assert(stub != NULL && "stub not created");
	354	fit->binding = ld::Fixup::bindingDirectlyBound;
	355	fit->u.target = stub;
	356	}
	357	}
	358	}
	359
	360	// sort new atoms so links are consistent
	361	for (std::vector<ld::Internal::FinalSection*>::iterator sit=state.sections.begin(); sit != state.sections.end(); ++sit) {
	362	ld::Internal::FinalSection* sect = *sit;
	363	switch ( sect->type() ) {
	364	case ld::Section::typeStubHelper:
	365	case ld::Section::typeStub:
	366	case ld::Section::typeStubClose:
	367	case ld::Section::typeLazyPointer:
	368	case ld::Section::typeLazyPointerClose:
	369	std::sort(sect->atoms.begin(), sect->atoms.end(), AtomByNameSorter());
	370	break;
	371	default:
	372	break;
	373	}
	374	}
	375
	376	}
	377
	378
	379	void doPass(const Options& opts, ld::Internal& internal)
	380	{
	381	Pass pass(opts);
	382	pass.process(internal);
	383	}
	384
	385
	386
	387	} // namespace stubs
	388	} // namespace passes
	389	} // namespace ld
	390