ld64-274.2.tar.gz

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

diff --git a/src/ld/passes/got.cpp b/src/ld/passes/got.cpp
index ff18e0036ed148e62fca1fcc797e24052ee9ae86..01c2e308ba53f0905b75a891ab0a22e7ce9b54a0 100644 (file)
--- a/src/ld/passes/got.cpp
+++ b/src/ld/passes/got.cpp
@@ -30,10 +30,11 @@
 
 #include <vector>
 #include <map>
 
 #include <vector>
 #include <map>

-#include <ext/hash_map>

 
 

+#include "MachOFileAbstraction.hpp"

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

+#include "configure.h"

 
 namespace ld {
 namespace passes {
 
 namespace ld {
 namespace passes {


@@ -43,19 +44,18 @@ class File; // forward reference
 
 class GOTEntryAtom : public ld::Atom {
 public:
 
 class GOTEntryAtom : public ld::Atom {
 public:

-                                                                                       GOTEntryAtom(ld::Internal& internal, const ld::Atom* target, bool weakImport)
-                               : ld::Atom(_s_section, ld::Atom::definitionRegular, ld::Atom::combineNever,
+                                                                                       GOTEntryAtom(ld::Internal& internal, const ld::Atom* target, bool weakImport, bool weakDef, bool is64)
+                               : ld::Atom(weakDef ? _s_sectionWeak : _s_section, ld::Atom::definitionRegular, ld::Atom::combineNever,

                                                        ld::Atom::scopeLinkageUnit, ld::Atom::typeNonLazyPointer, 
                                                        ld::Atom::scopeLinkageUnit, ld::Atom::typeNonLazyPointer, 

-                                                       symbolTableNotIn, false, false, false, ld::Atom::Alignment(3)), 
-                               _fixup(0, ld::Fixup::k1of1, ld::Fixup::kindStoreTargetAddressLittleEndian64, target),
-                               _target(target)
+                                                       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; }
                                        { _fixup.weakImport = weakImport; internal.addAtom(*this); }
 
        virtual const ld::File*                                 file() const                                    { return NULL; }

-       virtual bool                                                    translationUnitSource(const char** dir, const char**) const 
-                                                                                                                                                       { return false; }

        virtual const char*                                             name() const                                    { return _target->name(); }
        virtual const char*                                             name() const                                    { return _target->name(); }

-       virtual uint64_t                                                size() const                                    { return 8; }
+       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 uint64_t                                                objectAddress() const                   { return 0; }
        virtual void                                                    copyRawContent(uint8_t buffer[]) const { }
        virtual void                                                    setScope(Scope)                                 { }


@@ -65,17 +65,25 @@ public:
 private:
        mutable ld::Fixup                                               _fixup;
        const ld::Atom*                                                 _target;
 private:
        mutable ld::Fixup                                               _fixup;
        const ld::Atom*                                                 _target;

+       bool                                                                    _is64;

        
        static ld::Section                                              _s_section;
        
        static ld::Section                                              _s_section;

+       static ld::Section                                              _s_sectionWeak;

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

+ld::Section GOTEntryAtom::_s_sectionWeak("__DATA", "__got_weak", ld::Section::typeNonLazyPointer);

 
 
 
 

-static bool gotFixup(const Options& opts, ld::Internal& internal, const ld::Atom* targetOfGOT, const ld::Fixup* fixup, bool* optimizable)
+static bool gotFixup(const Options& opts, ld::Internal& internal, const ld::Atom* targetOfGOT, const ld::Fixup* fixup, bool* optimizable, bool* targetIsExternalWeakDef)

 {
 {

+       *targetIsExternalWeakDef = false;

        switch (fixup->kind) {
                case ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoad:
        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
                        // start by assuming this can be optimized
                        *optimizable = true;
                        // cannot do LEA optimization if target is in another dylib


@@ -87,10 +95,24 @@ static bool gotFixup(const Options& opts, ld::Internal& internal, const ld::Atom
                                                                                                || (targetOfGOT->section().type() == ld::Section::typeTentativeDefs)) ) {
                                *optimizable = false;
                        }
                                                                                                || (targetOfGOT->section().type() == ld::Section::typeTentativeDefs)) ) {
                                *optimizable = false;
                        }

-                       if ( targetOfGOT->scope() == ld::Atom::scopeGlobal ) {  
+                       if ( targetOfGOT->scope() == ld::Atom::scopeGlobal ) {

                                // cannot do LEA optimization if target is weak exported symbol
                                // cannot do LEA optimization if target is weak exported symbol

-                               if ( (targetOfGOT->definition() == ld::Atom::definitionRegular) && (targetOfGOT->combine() == ld::Atom::combineByName) )
-                                       *optimizable = false;
+                               if ( ((targetOfGOT->definition() == ld::Atom::definitionRegular) || (targetOfGOT->definition() == ld::Atom::definitionProxy)) && (targetOfGOT->combine() == ld::Atom::combineByName) ) {
+                                       switch ( opts.outputKind() ) {
+                                               case Options::kDynamicExecutable:
+                                               case Options::kDynamicLibrary:
+                                               case Options::kDynamicBundle:
+                                               case Options::kKextBundle:
+                                                       *targetIsExternalWeakDef = true;
+                                                       *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 interposable
                                if ( opts.interposable(targetOfGOT->name()) ) 
                                        *optimizable = false;


@@ -101,8 +123,23 @@ static bool gotFixup(const Options& opts, ld::Internal& internal, const ld::Atom
                                if ( opts.nameSpace() != Options::kTwoLevelNameSpace ) 
                                        *optimizable = false;
                        }
                                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:
                        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:
                        *optimizable = false;
                        return true;
                default:


@@ -128,11 +165,45 @@ void doPass(const Options& opts, ld::Internal& internal)
        if ( opts.outputKind() == Options::kObjectFile )
                return;
 
        if ( opts.outputKind() == Options::kObjectFile )
                return;
 

-       // walk all atoms and fixups looking for stubable references
-       // don't create stubs inline because that could invalidate the sections walk
+       // pre-fill gotMap with existing non-lazy pointers
+       std::map<const ld::Atom*, const ld::Atom*> gotMap;
+       for (ld::Internal::FinalSection* sect : internal.sections) {
+               if ( sect->type() != ld::Section::typeNonLazyPointer )
+                       continue;
+               for (const ld::Atom* atom : sect->atoms) {
+                       const ld::Atom* target = NULL;
+                       for (ld::Fixup::iterator fit = atom->fixupsBegin(), end=atom->fixupsEnd(); fit != end; ++fit) {
+                               switch (fit->kind) {
+                               case ld::Fixup::kindStoreTargetAddressLittleEndian64:
+                               case ld::Fixup::kindStoreTargetAddressLittleEndian32:
+                                       switch ( fit->binding ) {
+                                               case ld::Fixup::bindingsIndirectlyBound:
+                                                       target = internal.indirectBindingTable[fit->u.bindingIndex];
+                                                       break;
+                                               case ld::Fixup::bindingDirectlyBound:
+                                                       target = fit->u.target;
+                                                       break;
+                                               default:
+                                                       fprintf(stderr, "non-pointer is got entry\n");
+                                                       break;
+                                       }
+                                       break;
+                               default:
+                                       break;
+                               }
+                       }
+                       if ( target != NULL ) {
+                               if (log) fprintf(stderr, "found existing got entry to %s\n", target->name());
+                               gotMap[target] = atom;
+                       }
+               }
+       }
+
+       // 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::vector<const ld::Atom*> atomsReferencingGOT;

-       std::map<const ld::Atom*,ld::Atom*> gotMap;

        std::map<const ld::Atom*,bool>          weakImportMap;
        std::map<const ld::Atom*,bool>          weakImportMap;

+       std::map<const ld::Atom*,bool>          weakDefMap;

        atomsReferencingGOT.reserve(128);
        for (std::vector<ld::Internal::FinalSection*>::iterator sit=internal.sections.begin(); sit != internal.sections.end(); ++sit) {
                ld::Internal::FinalSection* sect = *sit;
        atomsReferencingGOT.reserve(128);
        for (std::vector<ld::Internal::FinalSection*>::iterator sit=internal.sections.begin(); sit != internal.sections.end(); ++sit) {
                ld::Internal::FinalSection* sect = *sit;


@@ -140,21 +211,25 @@ void doPass(const Options& opts, ld::Internal& internal)
                        const ld::Atom* atom = *ait;
                        bool atomUsesGOT = false;
                        const ld::Atom* targetOfGOT = NULL;
                        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];
                        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;
                                                break;
                                        case ld::Fixup::bindingDirectlyBound:
                                                targetOfGOT = fit->u.target;

+                                               targetIsWeakImport = fit->weakImport;

                                                break;
                     default:
                         break;   
                                }
                                bool optimizable;
                                                break;
                     default:
                         break;   
                                }
                                bool optimizable;

-                               if ( !gotFixup(opts, internal, targetOfGOT, fit, &optimizable) )
+                               bool targetIsExternalWeakDef;
+                               if ( !gotFixup(opts, internal, targetOfGOT, fit, &optimizable, &targetIsExternalWeakDef) )

                                        continue;
                                if ( optimizable ) {
                                        // change from load of GOT entry to lea of target
                                        continue;
                                if ( optimizable ) {
                                        // change from load of GOT entry to lea of target


@@ -164,7 +239,22 @@ void doPass(const Options& opts, ld::Internal& internal)
                                                case ld::Fixup::bindingDirectlyBound:
                                                        fit->binding = ld::Fixup::bindingDirectlyBound;
                                                        fit->u.target = targetOfGOT;
                                                case ld::Fixup::bindingDirectlyBound:
                                                        fit->binding = ld::Fixup::bindingDirectlyBound;
                                                        fit->u.target = targetOfGOT;

-                                                       fit->kind = ld::Fixup::kindStoreTargetAddressX86PCRel32GOTLoadNowLEA;
+                                                       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;
                                                default:
                                                        assert(0 && "unsupported GOT reference");


@@ -173,29 +263,25 @@ void doPass(const Options& opts, ld::Internal& internal)
                                }
                                else {
                                        // remember that we need to use GOT in this function
                                }
                                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 ( log ) fprintf(stderr, "found GOT use in %s\n", atom->name());

                                        if ( !atomUsesGOT ) {
                                                atomsReferencingGOT.push_back(atom);
                                                atomUsesGOT = true;
                                        }
                                        if ( !atomUsesGOT ) {
                                                atomsReferencingGOT.push_back(atom);
                                                atomUsesGOT = true;
                                        }

-                                       gotMap[targetOfGOT] = NULL;
+                                       if ( gotMap.count(targetOfGOT) == 0 )
+                                               gotMap[targetOfGOT] = NULL;
+                                       // record if target is weak def
+                                       weakDefMap[targetOfGOT] = targetIsExternalWeakDef;

                                        // 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
                                        // 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

-                                               weakImportMap[targetOfGOT] = fit->weakImport;
-                                               // <rdar://problem/5529626> If only weak_import symbols are used, linker should use LD_LOAD_WEAK_DYLIB
-                                               const ld::dylib::File* dylib = dynamic_cast<const ld::dylib::File*>(targetOfGOT->file());
-                                               if ( dylib != NULL ) {
-                                                       if ( fit->weakImport )
-                                                               (const_cast<ld::dylib::File*>(dylib))->setUsingWeakImportedSymbols();
-                                                       else
-                                                               (const_cast<ld::dylib::File*>(dylib))->setUsingNonWeakImportedSymbols();
-                                               }
+                                               if ( log ) fprintf(stderr, "weakImportMap[%s] = %d\n", targetOfGOT->name(), targetIsWeakImport);
+                                               weakImportMap[targetOfGOT] = targetIsWeakImport; 

                                        }
                                        else {
                                                // target in weakImportMap, check for weakness mismatch
                                        }
                                        else {
                                                // target in weakImportMap, check for weakness mismatch

-                                               if ( pos->second != fit->weakImport ) {
+                                               if ( pos->second != targetIsWeakImport ) {

                                                        // found mismatch
                                                        switch ( opts.weakReferenceMismatchTreatment() ) {
                                                                case Options::kWeakReferenceMismatchError:
                                                        // found mismatch
                                                        switch ( opts.weakReferenceMismatchTreatment() ) {
                                                                case Options::kWeakReferenceMismatchError:


@@ -214,11 +300,39 @@ void doPass(const Options& opts, ld::Internal& internal)
                }
        }
        
                }
        }
        

-       // 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]);
+       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 (auto& entry : gotMap) {
+               if ( entry.second == NULL ) {
+                       entry.second = new GOTEntryAtom(internal, entry.first, weakImportMap[entry.first], opts.useDataConstSegment() && weakDefMap[entry.first], is64);
+                       if (log) fprintf(stderr, "making new GOT slot for %s, gotMap[%p] = %p\n", entry.first->name(), entry.first, entry.second);
+               }
+       }
+
+

        // 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;
        // 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;


@@ -242,7 +356,8 @@ void doPass(const Options& opts, ld::Internal& internal)
                     break;    
                        }
                        bool optimizable;
                     break;    
                        }
                        bool optimizable;

-                       if ( (targetOfGOT == NULL) || !gotFixup(opts, internal, targetOfGOT, fit, &optimizable) )
+                       bool targetIsExternalWeakDef;
+                       if ( (targetOfGOT == NULL) || !gotFixup(opts, internal, targetOfGOT, fit, &optimizable, &targetIsExternalWeakDef) )

                                continue;
                        if ( !optimizable ) {
                                // GOT use not optimized away, update to bind to GOT entry
                                continue;
                        if ( !optimizable ) {
                                // GOT use not optimized away, update to bind to GOT entry


@@ -250,6 +365,7 @@ void doPass(const Options& opts, ld::Internal& internal)
                                switch ( fitThatSetTarget->binding ) {
                                        case ld::Fixup::bindingsIndirectlyBound:
                                        case ld::Fixup::bindingDirectlyBound:
                                switch ( fitThatSetTarget->binding ) {
                                        case ld::Fixup::bindingsIndirectlyBound:
                                        case ld::Fixup::bindingDirectlyBound:

+                                               if ( log ) fprintf(stderr, "updating GOT use in %s to %s\n", atom->name(), targetOfGOT->name());

                                                fitThatSetTarget->binding = ld::Fixup::bindingDirectlyBound;
                                                fitThatSetTarget->u.target = gotMap[targetOfGOT];
                                                break;
                                                fitThatSetTarget->binding = ld::Fixup::bindingDirectlyBound;
                                                fitThatSetTarget->u.target = gotMap[targetOfGOT];
                                                break;