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

/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
 *
 * Copyright (c) 2009 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 <dlfcn.h>

#include <vector>
#include <map>

#include "MachOFileAbstraction.hpp"
#include "ld.hpp"
#include "got.h"
#include "configure.h"

namespace ld {
namespace passes {
namespace got {

class File; // forward reference

class GOTEntryAtom : public ld::Atom {
public:
											GOTEntryAtom(ld::Internal& internal, const ld::Atom* target, bool weakImport, bool is64)
				: ld::Atom(_s_section, ld::Atom::definitionRegular, ld::Atom::combineNever,
							ld::Atom::scopeLinkageUnit, ld::Atom::typeNonLazyPointer, 
							symbolTableNotIn, false, false, false, (is64 ? ld::Atom::Alignment(3) : ld::Atom::Alignment(2))),
				_fixup(0, ld::Fixup::k1of1, (is64 ? ld::Fixup::kindStoreTargetAddressLittleEndian64 : ld::Fixup::kindStoreTargetAddressLittleEndian32), target),
				_target(target),
				_is64(is64)
					{ _fixup.weakImport = weakImport; internal.addAtom(*this); }

	virtual const ld::File*					file() const					{ return NULL; }
	virtual const char*						name() const					{ return _target->name(); }
	virtual uint64_t						size() const					{ return (_is64 ? 8 : 4); }
	virtual uint64_t						objectAddress() const			{ return 0; }
	virtual void							copyRawContent(uint8_t buffer[]) const { }
	virtual void							setScope(Scope)					{ }
	virtual ld::Fixup::iterator				fixupsBegin() const				{ return &_fixup; }
	virtual ld::Fixup::iterator				fixupsEnd()	const 				{ return &((ld::Fixup*)&_fixup)[1]; }

private:
	mutable ld::Fixup						_fixup;
	const ld::Atom*							_target;
	bool									_is64;
	
	static ld::Section						_s_section;
};

ld::Section GOTEntryAtom::_s_section("__DATA", "__got", ld::Section::typeNonLazyPointer);


static bool gotFixup(const Options& opts, ld::Internal& internal, const ld::Atom* targetOfGOT, const ld::Fixup* fixup, bool* optimizable)
{
	switch (fixup->kind) {
		case ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoad:
#if SUPPORT_ARCH_arm64
		case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPage21:
		case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPageOff12:
#endif
			// start by assuming this can be optimized
			*optimizable = true;
			// cannot do LEA optimization if target is in another dylib
			if ( targetOfGOT->definition() == ld::Atom::definitionProxy ) 
				*optimizable = false;
			// cannot do LEA optimization if target in __huge section
			if ( internal.usingHugeSections && (targetOfGOT->size() > 1024*1024)
											&& (   (targetOfGOT->section().type() == ld::Section::typeZeroFill)
												|| (targetOfGOT->section().type() == ld::Section::typeTentativeDefs)) ) {
				*optimizable = false;
			}
			if ( targetOfGOT->scope() == ld::Atom::scopeGlobal ) {	
				// cannot do LEA optimization if target is weak exported symbol
				if ( (targetOfGOT->definition() == ld::Atom::definitionRegular) && (targetOfGOT->combine() == ld::Atom::combineByName) ) {
					switch ( opts.outputKind() ) {
						case Options::kDynamicExecutable:
						case Options::kDynamicLibrary:
						case Options::kDynamicBundle:
						case Options::kKextBundle:
							*optimizable = false;
							break;
						case Options::kStaticExecutable:
						case Options::kDyld:
						case Options::kPreload:
						case Options::kObjectFile:
							break;
					}
				}
				// cannot do LEA optimization if target is interposable
				if ( opts.interposable(targetOfGOT->name()) ) 
					*optimizable = false;
				// cannot do LEA optimization if target is resolver function
				if ( targetOfGOT->contentType() == ld::Atom::typeResolver ) 
					*optimizable = false;
				// cannot do LEA optimization for flat-namespace
				if ( opts.nameSpace() != Options::kTwoLevelNameSpace ) 
					*optimizable = false;
			}
			else if ( targetOfGOT->scope() == ld::Atom::scopeLinkageUnit) {
				// <rdar://problem/12379969> don't do optimization if target is in custom segment
				if ( opts.sharedRegionEligible() ) {
					const char* segName = targetOfGOT->section().segmentName();
					if ( (strcmp(segName, "__TEXT") != 0) && (strcmp(segName, "__DATA") != 0) ) {
						*optimizable = false;
					}
				}
			}
			return true;
		case ld::Fixup::kindStoreX86PCRel32GOT:
#if SUPPORT_ARCH_arm64
		case ld::Fixup::kindStoreARM64PCRelToGOT:
#endif
			*optimizable = false;
			return true;
		case ld::Fixup::kindNoneGroupSubordinatePersonality:
			*optimizable = false;
			return true;
		default:
			break;
	}
	
	return false;
}

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

void doPass(const Options& opts, ld::Internal& internal)
{
	const bool log = false;
	
	// only make got section in final linked images
	if ( opts.outputKind() == Options::kObjectFile )
		return;

	// walk all atoms and fixups looking for GOT-able references
	// don't create GOT atoms during this loop because that could invalidate the sections iterator
	std::vector<const ld::Atom*> atomsReferencingGOT;
	std::map<const ld::Atom*,ld::Atom*> gotMap;
	std::map<const ld::Atom*,bool>		weakImportMap;
	atomsReferencingGOT.reserve(128);
	for (std::vector<ld::Internal::FinalSection*>::iterator sit=internal.sections.begin(); sit != internal.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;
			bool atomUsesGOT = false;
			const ld::Atom* targetOfGOT = NULL;
			bool targetIsWeakImport = false;
			for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
				if ( fit->firstInCluster() ) 
					targetOfGOT = NULL;
				switch ( fit->binding ) {
					case ld::Fixup::bindingsIndirectlyBound:
						targetOfGOT = internal.indirectBindingTable[fit->u.bindingIndex];
						targetIsWeakImport = fit->weakImport;
						break;
					case ld::Fixup::bindingDirectlyBound:
						targetOfGOT = fit->u.target;
						targetIsWeakImport = fit->weakImport;
						break;
                    default:
                        break;   
				}
				bool optimizable;
				if ( !gotFixup(opts, internal, targetOfGOT, fit, &optimizable) )
					continue;
				if ( optimizable ) {
					// change from load of GOT entry to lea of target
					if ( log ) fprintf(stderr, "optimized GOT usage in %s to %s\n", atom->name(), targetOfGOT->name());
					switch ( fit->binding ) {
						case ld::Fixup::bindingsIndirectlyBound:
						case ld::Fixup::bindingDirectlyBound:
							fit->binding = ld::Fixup::bindingDirectlyBound;
							fit->u.target = targetOfGOT;
							switch ( fit->kind ) {
								case ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoad:
									fit->kind = ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoadNowLEA;
									break;
#if SUPPORT_ARCH_arm64
								case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPage21:
									fit->kind = ld::Fixup::kindStoreTargetAddressARM64GOTLeaPage21;
									break;
								case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPageOff12:
									fit->kind = ld::Fixup::kindStoreTargetAddressARM64GOTLeaPageOff12;
									break;
#endif
								default:
									assert(0 && "unsupported GOT reference kind");
									break;
							}
							break;
						default:
							assert(0 && "unsupported GOT reference");
							break;
					}
				}
				else {
					// remember that we need to use GOT in this function
					if ( log ) fprintf(stderr, "found GOT use in %s to %s\n", atom->name(), targetOfGOT->name());
					if ( !atomUsesGOT ) {
						atomsReferencingGOT.push_back(atom);
						atomUsesGOT = true;
					}
					gotMap[targetOfGOT] = NULL;
					// record weak_import attribute
					std::map<const ld::Atom*,bool>::iterator pos = weakImportMap.find(targetOfGOT);
					if ( pos == weakImportMap.end() ) {
						// target not in weakImportMap, so add
						if ( log ) fprintf(stderr, "weakImportMap[%s] = %d\n", targetOfGOT->name(), targetIsWeakImport);
						weakImportMap[targetOfGOT] = targetIsWeakImport; 
					}
					else {
						// target in weakImportMap, check for weakness mismatch
						if ( pos->second != targetIsWeakImport ) {
							// found mismatch
							switch ( opts.weakReferenceMismatchTreatment() ) {
								case Options::kWeakReferenceMismatchError:
									throwf("mismatching weak references for symbol: %s", targetOfGOT->name());
								case Options::kWeakReferenceMismatchWeak:
									pos->second = true;
									break;
								case Options::kWeakReferenceMismatchNonWeak:
									pos->second = false;
									break;
							}
						}
					}
				}
			}
		}
	}
	
	bool is64 = false;
	switch ( opts.architecture() ) {
#if SUPPORT_ARCH_i386
		case CPU_TYPE_I386:
			is64 = false;
			break;
#endif
#if SUPPORT_ARCH_x86_64
		case CPU_TYPE_X86_64:
			is64 = true;
			break;
#endif
#if SUPPORT_ARCH_arm_any
		case CPU_TYPE_ARM: 
			is64 = false;
			break;
#endif
#if SUPPORT_ARCH_arm64
		case CPU_TYPE_ARM64: 
			is64 = true;
			break;
#endif
	}
	
	// make GOT entries	
	for (std::map<const ld::Atom*,ld::Atom*>::iterator it = gotMap.begin(); it != gotMap.end(); ++it) {
		it->second = new GOTEntryAtom(internal, it->first, weakImportMap[it->first], is64);
	}
	
	// update atoms to use GOT entries
	for (std::vector<const ld::Atom*>::iterator it=atomsReferencingGOT.begin(); it != atomsReferencingGOT.end(); ++it) {
		const ld::Atom* atom = *it;
		const ld::Atom* targetOfGOT = NULL;
		ld::Fixup::iterator fitThatSetTarget = NULL;
		for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
			if ( fit->firstInCluster() ) {
				targetOfGOT = NULL;
				fitThatSetTarget = NULL;
			}
			switch ( fit->binding ) {
				case ld::Fixup::bindingsIndirectlyBound:
					targetOfGOT = internal.indirectBindingTable[fit->u.bindingIndex];
					fitThatSetTarget = fit;
					break;
				case ld::Fixup::bindingDirectlyBound:
					targetOfGOT = fit->u.target;
					fitThatSetTarget = fit;
					break;
                default:
                    break;    
			}
			bool optimizable;
			if ( (targetOfGOT == NULL) || !gotFixup(opts, internal, targetOfGOT, fit, &optimizable) )
				continue;
			if ( !optimizable ) {
				// GOT use not optimized away, update to bind to GOT entry
				assert(fitThatSetTarget != NULL);
				switch ( fitThatSetTarget->binding ) {
					case ld::Fixup::bindingsIndirectlyBound:
					case ld::Fixup::bindingDirectlyBound:
						fitThatSetTarget->binding = ld::Fixup::bindingDirectlyBound;
						fitThatSetTarget->u.target = gotMap[targetOfGOT];
						break;
					default:
						assert(0 && "unsupported GOT reference");
						break;
				}
			}
		}
	}
	
	// sort new atoms so links are consistent
	for (std::vector<ld::Internal::FinalSection*>::iterator sit=internal.sections.begin(); sit != internal.sections.end(); ++sit) {
		ld::Internal::FinalSection* sect = *sit;
		if ( sect->type() == ld::Section::typeNonLazyPointer ) {
			std::sort(sect->atoms.begin(), sect->atoms.end(), AtomByNameSorter());
		}
	}
}


} // namespace got
} // namespace passes 
} // namespace ld
Commit	Line	Data
a645023d A	1	/* -- mode: C++; c-basic-offset: 4; tab-width: 4 --
	2	*
	3	* Copyright (c) 2009 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	#include <stdint.h>
	27	#include <math.h>
	28	#include <unistd.h>
	29	#include <dlfcn.h>
	30
	31	#include <vector>
	32	#include <map>
a645023d	33
f80fe69f	34	#include "MachOFileAbstraction.hpp"
a645023d A	35	#include "ld.hpp"
a645023d A	36	#include "got.h"
f80fe69f	37	#include "configure.h"
a645023d A	38
	39	namespace ld {
	40	namespace passes {
	41	namespace got {
	42
	43	class File; // forward reference
	44
	45	class GOTEntryAtom : public ld::Atom {
	46	public:
f80fe69f	47	GOTEntryAtom(ld::Internal& internal, const ld::Atom* target, bool weakImport, bool is64)
a645023d A	48	: ld::Atom(_s_section, ld::Atom::definitionRegular, ld::Atom::combineNever,
a645023d A	49	ld::Atom::scopeLinkageUnit, ld::Atom::typeNonLazyPointer,
f80fe69f A	50	symbolTableNotIn, false, false, false, (is64 ? ld::Atom::Alignment(3) : ld::Atom::Alignment(2))),
	51	_fixup(0, ld::Fixup::k1of1, (is64 ? ld::Fixup::kindStoreTargetAddressLittleEndian64 : ld::Fixup::kindStoreTargetAddressLittleEndian32), target),
	52	_target(target),
	53	_is64(is64)
a645023d A	54	{ _fixup.weakImport = weakImport; internal.addAtom(*this); }
	55
	56	virtual const ld::File* file() const { return NULL; }
a645023d	57	virtual const char* name() const { return _target->name(); }
f80fe69f	58	virtual uint64_t size() const { return (_is64 ? 8 : 4); }
a645023d A	59	virtual uint64_t objectAddress() const { return 0; }
	60	virtual void copyRawContent(uint8_t buffer[]) const { }
	61	virtual void setScope(Scope) { }
	62	virtual ld::Fixup::iterator fixupsBegin() const { return &_fixup; }
	63	virtual ld::Fixup::iterator fixupsEnd() const { return &((ld::Fixup*)&_fixup)[1]; }
	64
	65	private:
	66	mutable ld::Fixup _fixup;
	67	const ld::Atom* _target;
f80fe69f	68	bool _is64;
a645023d A	69
	70	static ld::Section _s_section;
	71	};
	72
	73	ld::Section GOTEntryAtom::_s_section("__DATA", "__got", ld::Section::typeNonLazyPointer);
	74
	75
	76	static bool gotFixup(const Options& opts, ld::Internal& internal, const ld::Atom* targetOfGOT, const ld::Fixup* fixup, bool* optimizable)
	77	{
	78	switch (fixup->kind) {
	79	case ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoad:
f80fe69f A	80	#if SUPPORT_ARCH_arm64
	81	case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPage21:
	82	case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPageOff12:
	83	#endif
a645023d A	84	// start by assuming this can be optimized
	85	*optimizable = true;
	86	// cannot do LEA optimization if target is in another dylib
	87	if ( targetOfGOT->definition() == ld::Atom::definitionProxy )
	88	*optimizable = false;
	89	// cannot do LEA optimization if target in __huge section
	90	if ( internal.usingHugeSections && (targetOfGOT->size() > 1024*1024)
	91	&& ( (targetOfGOT->section().type() == ld::Section::typeZeroFill)
	92	\|\| (targetOfGOT->section().type() == ld::Section::typeTentativeDefs)) ) {
	93	*optimizable = false;
	94	}
	95	if ( targetOfGOT->scope() == ld::Atom::scopeGlobal ) {
	96	// cannot do LEA optimization if target is weak exported symbol
b2fa67a8 A	97	if ( (targetOfGOT->definition() == ld::Atom::definitionRegular) && (targetOfGOT->combine() == ld::Atom::combineByName) ) {
	98	switch ( opts.outputKind() ) {
	99	case Options::kDynamicExecutable:
	100	case Options::kDynamicLibrary:
	101	case Options::kDynamicBundle:
	102	case Options::kKextBundle:
	103	*optimizable = false;
	104	break;
	105	case Options::kStaticExecutable:
	106	case Options::kDyld:
	107	case Options::kPreload:
	108	case Options::kObjectFile:
	109	break;
	110	}
	111	}
a645023d A	112	// cannot do LEA optimization if target is interposable
	113	if ( opts.interposable(targetOfGOT->name()) )
	114	*optimizable = false;
	115	// cannot do LEA optimization if target is resolver function
	116	if ( targetOfGOT->contentType() == ld::Atom::typeResolver )
	117	*optimizable = false;
	118	// cannot do LEA optimization for flat-namespace
	119	if ( opts.nameSpace() != Options::kTwoLevelNameSpace )
	120	*optimizable = false;
	121	}
d425e388 A	122	else if ( targetOfGOT->scope() == ld::Atom::scopeLinkageUnit) {
	123	// <rdar://problem/12379969> don't do optimization if target is in custom segment
	124	if ( opts.sharedRegionEligible() ) {
	125	const char* segName = targetOfGOT->section().segmentName();
	126	if ( (strcmp(segName, "__TEXT") != 0) && (strcmp(segName, "__DATA") != 0) ) {
	127	*optimizable = false;
	128	}
	129	}
	130	}
a645023d A	131	return true;
a645023d A	132	case ld::Fixup::kindStoreX86PCRel32GOT:
f80fe69f A	133	#if SUPPORT_ARCH_arm64
	134	case ld::Fixup::kindStoreARM64PCRelToGOT:
	135	#endif
a645023d A	136	*optimizable = false;
a645023d A	137	return true;
afe874b1 A	138	case ld::Fixup::kindNoneGroupSubordinatePersonality:
	139	*optimizable = false;
	140	return true;
a645023d A	141	default:
	142	break;
	143	}
	144
	145	return false;
	146	}
	147
	148	struct AtomByNameSorter
	149	{
	150	bool operator()(const ld::Atom* left, const ld::Atom* right)
	151	{
	152	return (strcmp(left->name(), right->name()) < 0);
	153	}
	154	};
	155
	156	void doPass(const Options& opts, ld::Internal& internal)
	157	{
	158	const bool log = false;
	159
	160	// only make got section in final linked images
	161	if ( opts.outputKind() == Options::kObjectFile )
	162	return;
	163
afe874b1 A	164	// walk all atoms and fixups looking for GOT-able references
afe874b1 A	165	// don't create GOT atoms during this loop because that could invalidate the sections iterator
a645023d A	166	std::vector<const ld::Atom*> atomsReferencingGOT;
	167	std::map<const ld::Atom,ld::Atom> gotMap;
	168	std::map<const ld::Atom*,bool> weakImportMap;
	169	atomsReferencingGOT.reserve(128);
	170	for (std::vector<ld::Internal::FinalSection*>::iterator sit=internal.sections.begin(); sit != internal.sections.end(); ++sit) {
	171	ld::Internal::FinalSection* sect = *sit;
	172	for (std::vector<const ld::Atom*>::iterator ait=sect->atoms.begin(); ait != sect->atoms.end(); ++ait) {
	173	const ld::Atom* atom = *ait;
	174	bool atomUsesGOT = false;
	175	const ld::Atom* targetOfGOT = NULL;
afe874b1	176	bool targetIsWeakImport = false;
a645023d A	177	for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
	178	if ( fit->firstInCluster() )
	179	targetOfGOT = NULL;
	180	switch ( fit->binding ) {
	181	case ld::Fixup::bindingsIndirectlyBound:
	182	targetOfGOT = internal.indirectBindingTable[fit->u.bindingIndex];
afe874b1	183	targetIsWeakImport = fit->weakImport;
a645023d A	184	break;
	185	case ld::Fixup::bindingDirectlyBound:
	186	targetOfGOT = fit->u.target;
afe874b1	187	targetIsWeakImport = fit->weakImport;
a645023d A	188	break;
	189	default:
	190	break;
	191	}
	192	bool optimizable;
	193	if ( !gotFixup(opts, internal, targetOfGOT, fit, &optimizable) )
	194	continue;
	195	if ( optimizable ) {
	196	// change from load of GOT entry to lea of target
	197	if ( log ) fprintf(stderr, "optimized GOT usage in %s to %s\n", atom->name(), targetOfGOT->name());
	198	switch ( fit->binding ) {
	199	case ld::Fixup::bindingsIndirectlyBound:
	200	case ld::Fixup::bindingDirectlyBound:
	201	fit->binding = ld::Fixup::bindingDirectlyBound;
	202	fit->u.target = targetOfGOT;
f80fe69f A	203	switch ( fit->kind ) {
	204	case ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoad:
	205	fit->kind = ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoadNowLEA;
	206	break;
	207	#if SUPPORT_ARCH_arm64
	208	case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPage21:
	209	fit->kind = ld::Fixup::kindStoreTargetAddressARM64GOTLeaPage21;
	210	break;
	211	case ld::Fixup::kindStoreTargetAddressARM64GOTLoadPageOff12:
	212	fit->kind = ld::Fixup::kindStoreTargetAddressARM64GOTLeaPageOff12;
	213	break;
	214	#endif
	215	default:
	216	assert(0 && "unsupported GOT reference kind");
	217	break;
	218	}
a645023d A	219	break;
	220	default:
	221	assert(0 && "unsupported GOT reference");
	222	break;
	223	}
	224	}
	225	else {
	226	// remember that we need to use GOT in this function
	227	if ( log ) fprintf(stderr, "found GOT use in %s to %s\n", atom->name(), targetOfGOT->name());
	228	if ( !atomUsesGOT ) {
	229	atomsReferencingGOT.push_back(atom);
	230	atomUsesGOT = true;
	231	}
	232	gotMap[targetOfGOT] = NULL;
	233	// record weak_import attribute
	234	std::map<const ld::Atom*,bool>::iterator pos = weakImportMap.find(targetOfGOT);
	235	if ( pos == weakImportMap.end() ) {
	236	// target not in weakImportMap, so add
afe874b1 A	237	if ( log ) fprintf(stderr, "weakImportMap[%s] = %d\n", targetOfGOT->name(), targetIsWeakImport);
afe874b1 A	238	weakImportMap[targetOfGOT] = targetIsWeakImport;
a645023d A	239	}
	240	else {
	241	// target in weakImportMap, check for weakness mismatch
afe874b1	242	if ( pos->second != targetIsWeakImport ) {
a645023d A	243	// found mismatch
	244	switch ( opts.weakReferenceMismatchTreatment() ) {
	245	case Options::kWeakReferenceMismatchError:
	246	throwf("mismatching weak references for symbol: %s", targetOfGOT->name());
	247	case Options::kWeakReferenceMismatchWeak:
	248	pos->second = true;
	249	break;
	250	case Options::kWeakReferenceMismatchNonWeak:
	251	pos->second = false;
	252	break;
	253	}
	254	}
	255	}
	256	}
	257	}
	258	}
	259	}
	260
f80fe69f A	261	bool is64 = false;
	262	switch ( opts.architecture() ) {
	263	#if SUPPORT_ARCH_i386
	264	case CPU_TYPE_I386:
	265	is64 = false;
	266	break;
	267	#endif
	268	#if SUPPORT_ARCH_x86_64
	269	case CPU_TYPE_X86_64:
	270	is64 = true;
	271	break;
	272	#endif
	273	#if SUPPORT_ARCH_arm_any
	274	case CPU_TYPE_ARM:
	275	is64 = false;
	276	break;
	277	#endif
	278	#if SUPPORT_ARCH_arm64
	279	case CPU_TYPE_ARM64:
	280	is64 = true;
	281	break;
	282	#endif
	283	}
	284
a645023d A	285	// make GOT entries
a645023d A	286	for (std::map<const ld::Atom,ld::Atom>::iterator it = gotMap.begin(); it != gotMap.end(); ++it) {
f80fe69f	287	it->second = new GOTEntryAtom(internal, it->first, weakImportMap[it->first], is64);
a645023d A	288	}
	289
	290	// update atoms to use GOT entries
	291	for (std::vector<const ld::Atom*>::iterator it=atomsReferencingGOT.begin(); it != atomsReferencingGOT.end(); ++it) {
	292	const ld::Atom* atom = *it;
	293	const ld::Atom* targetOfGOT = NULL;
	294	ld::Fixup::iterator fitThatSetTarget = NULL;
	295	for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
	296	if ( fit->firstInCluster() ) {
	297	targetOfGOT = NULL;
	298	fitThatSetTarget = NULL;
	299	}
	300	switch ( fit->binding ) {
	301	case ld::Fixup::bindingsIndirectlyBound:
	302	targetOfGOT = internal.indirectBindingTable[fit->u.bindingIndex];
	303	fitThatSetTarget = fit;
	304	break;
	305	case ld::Fixup::bindingDirectlyBound:
	306	targetOfGOT = fit->u.target;
	307	fitThatSetTarget = fit;
	308	break;
	309	default:
	310	break;
	311	}
	312	bool optimizable;
	313	if ( (targetOfGOT == NULL) \|\| !gotFixup(opts, internal, targetOfGOT, fit, &optimizable) )
	314	continue;
	315	if ( !optimizable ) {
	316	// GOT use not optimized away, update to bind to GOT entry
	317	assert(fitThatSetTarget != NULL);
	318	switch ( fitThatSetTarget->binding ) {
	319	case ld::Fixup::bindingsIndirectlyBound:
	320	case ld::Fixup::bindingDirectlyBound:
	321	fitThatSetTarget->binding = ld::Fixup::bindingDirectlyBound;
	322	fitThatSetTarget->u.target = gotMap[targetOfGOT];
	323	break;
	324	default:
	325	assert(0 && "unsupported GOT reference");
	326	break;
	327	}
	328	}
	329	}
	330	}
	331
	332	// sort new atoms so links are consistent
	333	for (std::vector<ld::Internal::FinalSection*>::iterator sit=internal.sections.begin(); sit != internal.sections.end(); ++sit) {
	334	ld::Internal::FinalSection* sect = *sit;
	335	if ( sect->type() == ld::Section::typeNonLazyPointer ) {
	336	std::sort(sect->atoms.begin(), sect->atoms.end(), AtomByNameSorter());
	337	}
	338	}
	339	}
	340
	341
	342	} // namespace got
	343	} // namespace passes
	344	} // namespace ld