[WIP] rt.sections_elf_shared: Add support for OSX (prepare for shared Phobos lib)

src/rt/sections_elf_shared.d

@@ -17,7 +17,11 @@ else version (NetBSD) enum SharedELF = true;
 else version (DragonFlyBSD) enum SharedELF = true;
 else version (CRuntime_UClibc) enum SharedELF = true;
 else enum SharedELF = false;
-static if (SharedELF):
+
+version (OSX) enum SharedDarwin = true;
+else enum SharedDarwin = false;
+
+static if (SharedELF): // TODO: SharedDarwin too
 
 // debug = PRINTF;
 import core.memory;
@@ -36,6 +40,15 @@ else version (FreeBSD)
     import core.sys.freebsd.sys.elf;
     import core.sys.freebsd.sys.link_elf;
 }
+else version (OSX)
+{
+    import core.sys.osx.dlfcn;
+    import core.sys.osx.mach.dyld;
+    import core.sys.osx.mach.getsect;
+
+    extern(C) intptr_t _dyld_get_image_slide(const mach_header*) nothrow @nogc;
+    extern(C) mach_header* _dyld_get_image_header_containing_address(const void *addr) nothrow @nogc;
+}
 else version (NetBSD)
 {
     import core.sys.netbsd.dlfcn;
@@ -94,6 +107,7 @@ struct DSO
 
     @property immutable(FuncTable)[] ehTables() const nothrow @nogc
     {
+        // TODO: possibly required for OSX
         return null;
     }
 
@@ -108,13 +122,24 @@ private:
     {
         assert(_moduleGroup.modules.length);
         version (CRuntime_UClibc) {} else
-        assert(_tlsMod || !_tlsSize);
+        static if (SharedELF)
+        {
+            assert(_tlsMod || !_tlsSize);
+        }
     }
 
+    void** _slot;
     ModuleGroup _moduleGroup;
     Array!(void[]) _gcRanges;
-    size_t _tlsMod;
-    size_t _tlsSize;
+    static if (SharedELF)
+    {
+        size_t _tlsMod;
+        size_t _tlsSize;
+    }
+    else static if (SharedDarwin)
+    {
+        GetTLSAnchor _getTLSAnchor;
+    }
 
     version (Shared)
     {
@@ -126,7 +151,15 @@ private:
     // get the TLS range for the executing thread
     void[] tlsRange() const nothrow @nogc
     {
-        return getTLSRange(_tlsMod, _tlsSize);
+        static if (SharedELF)
+        {
+            return getTLSRange(_tlsMod, _tlsSize);
+        }
+        else static if (SharedDarwin)
+        {
+            return getTLSRange(_getTLSAnchor());
+        }
+        else static assert(0, "unimplemented");
     }
 }
 
@@ -198,7 +231,7 @@ version (Shared)
             if (tdso._addCnt)
             {
                 // Increment the dlopen ref for explicitly loaded libraries to pin them.
-                .dlopen(linkMapForHandle(tdso._pdso._handle).l_name, RTLD_LAZY) !is null || assert(0);
+                .dlopen(nameForDSO(tdso._pdso), RTLD_LAZY) !is null || assert(0);
                 (*res)[i]._addCnt = 1; // new array takes over the additional ref count
             }
         }
@@ -319,17 +352,20 @@ version (Shared)
     bool _rtLoading;
 
     /*
-     * Hash table to map link_map* to corresponding DSO*.
-     * The hash table is protected by a Mutex.
+     * Hash table to map the native handle (as returned by dlopen)
+     * to the corresponding DSO*, protected by a mutex.
      */
     __gshared pthread_mutex_t _handleToDSOMutex;
     __gshared HashTab!(void*, DSO*) _handleToDSO;
 
-    /*
-     * Section in executable that contains copy relocations.
-     * Might be null when druntime is dynamically loaded by a C host.
-     */
-    __gshared const(void)[] _copyRelocSection;
+    static if (SharedELF)
+    {
+        /*
+         * Section in executable that contains copy relocations.
+         * Might be null when druntime is dynamically loaded by a C host.
+         */
+        __gshared const(void)[] _copyRelocSection;
+    }
 }
 else
 {
@@ -352,6 +388,12 @@ else
 // Compiler to runtime interface.
 ///////////////////////////////////////////////////////////////////////////////
 
+version (OSX)
+    private alias ImageHeader = mach_header*;
+else
+    private alias ImageHeader = dl_phdr_info;
+
+extern(C) alias GetTLSAnchor = void* function() nothrow @nogc;
 
 /*
  * This data structure is generated by the compiler, and then passed to
@@ -362,6 +404,7 @@ struct CompilerDSOData
     size_t _version;                                       // currently 1
     void** _slot;                                          // can be used to store runtime data
     immutable(object.ModuleInfo*)* _minfo_beg, _minfo_end; // array of modules in this object file
+    static if (SharedDarwin) GetTLSAnchor _getTLSAnchor;
 }
 
 T[] toRange(T)(T* beg, T* end) { return beg[0 .. end - beg]; }
@@ -384,20 +427,23 @@ extern(C) void _d_dso_registry(CompilerDSOData* data)
 
         DSO* pdso = cast(DSO*).calloc(1, DSO.sizeof);
         assert(typeid(DSO).initializer().ptr is null);
+        pdso._slot = data._slot;
         *data._slot = pdso; // store backlink in library record
 
         pdso._moduleGroup = ModuleGroup(toRange(data._minfo_beg, data._minfo_end));
 
-        dl_phdr_info info = void;
-        findDSOInfoForAddr(data._slot, &info) || assert(0);
+        static if (SharedDarwin) pdso._getTLSAnchor = data._getTLSAnchor;
 
-        scanSegments(info, pdso);
+        ImageHeader header = void;
+        findImageHeaderForAddr(data._slot, &header) || assert(0);
+
+        scanSegments(header, pdso);
 
         version (Shared)
         {
             auto handle = handleForAddr(data._slot);
 
-            getDependencies(info, pdso._deps);
+            getDependencies(header, pdso._deps);
             pdso._handle = handle;
             setDSOForHandle(pdso, pdso._handle);
 
@@ -627,21 +673,13 @@ void freeDSO(DSO* pdso) nothrow @nogc
 version (Shared)
 {
 @nogc nothrow:
-    link_map* linkMapForHandle(void* handle)
+    const(char)* nameForDSO(in DSO* pdso)
     {
-        link_map* map;
-        dlinfo(handle, RTLD_DI_LINKMAP, &map) == 0 || assert(0);
-        return map;
+        Dl_info info = void;
+        dladdr(pdso._slot, &info) || assert(0);
+        return info.dli_fname;
     }
 
-     link_map* exeLinkMap(link_map* map)
-     {
-         assert(map);
-         while (map.l_prev !is null)
-             map = map.l_prev;
-         return map;
-     }
-
     DSO* dsoForHandle(void* handle)
     {
         DSO* pdso;
@@ -668,7 +706,7 @@ version (Shared)
         !pthread_mutex_unlock(&_handleToDSOMutex) || assert(0);
     }
 
-    void getDependencies(in ref dl_phdr_info info, ref Array!(DSO*) deps)
+    static if (SharedELF) void getDependencies(in ref dl_phdr_info info, ref Array!(DSO*) deps)
     {
         // get the entries of the .dynamic section
         ElfW!"Dyn"[] dyns;
@@ -719,6 +757,10 @@ version (Shared)
                 deps.insertBack(pdso); // append it to the dependencies
         }
     }
+    else static if (SharedDarwin) void getDependencies(in ImageHeader info, ref Array!(DSO*) deps)
+    {
+        // FIXME: Not implemented yet.
+    }
 
     void* handleForName(const char* name)
     {
@@ -733,10 +775,10 @@ version (Shared)
 ///////////////////////////////////////////////////////////////////////////////
 
 /************
- * Scan segments in Linux dl_phdr_info struct and store
+ * Scan segments in the image header and store
  * the TLS and writeable data segments in *pdso.
  */
-void scanSegments(in ref dl_phdr_info info, DSO* pdso) nothrow @nogc
+static if (SharedELF) void scanSegments(in ref dl_phdr_info info, DSO* pdso) nothrow @nogc
 {
     foreach (ref phdr; info.dlpi_phdr[0 .. info.dlpi_phnum])
     {
@@ -771,6 +813,27 @@ void scanSegments(in ref dl_phdr_info info, DSO* pdso) nothrow @nogc
         }
     }
 }
+else static if (SharedDarwin) void scanSegments(mach_header* info, DSO* pdso)
+{
+    import rt.mach_utils;
+
+    immutable slide = _dyld_get_image_slide(info);
+    foreach (e; dataSections)
+    {
+        auto sect = getSection(info, slide, e.seg, e.sect);
+        if (sect != null)
+            pdso._gcRanges.insertBack((cast(void*)sect.ptr)[0 .. sect.length]);
+    }
+
+    version (Shared)
+    {
+        auto text = getSection(info, slide, "__TEXT", "__text");
+        if (!text) {
+            assert(0, "Failed to get text section.");
+        }
+        pdso._codeSegments.insertBack(cast(void[])text);
+    }
+}
 
 /**************************
  * Input:
@@ -780,7 +843,7 @@ void scanSegments(in ref dl_phdr_info info, DSO* pdso) nothrow @nogc
  * References:
  *      http://linux.die.net/man/3/dl_iterate_phdr
  */
-bool findDSOInfoForAddr(in void* addr, dl_phdr_info* result=null) nothrow @nogc
+bool findImageHeaderForAddr(in void* addr, ImageHeader* result=null) nothrow @nogc
 {
     version (linux)       enum IterateManually = true;
     else version (NetBSD) enum IterateManually = true;
@@ -809,6 +872,12 @@ bool findDSOInfoForAddr(in void* addr, dl_phdr_info* result=null) nothrow @nogc
          */
         return dl_iterate_phdr(&callback, &dg) != 0;
     }
+    else version (OSX)
+    {
+        auto header = _dyld_get_image_header_containing_address(addr);
+        if (result) *result = header;
+        return !!header;
+    }
     else version (FreeBSD)
     {
         return !!_rtld_addr_phdr(addr, result);
@@ -825,7 +894,7 @@ bool findDSOInfoForAddr(in void* addr, dl_phdr_info* result=null) nothrow @nogc
  * Determine if 'addr' lies within shared object 'info'.
  * If so, return true and fill in 'result' with the corresponding ELF program header.
  */
-bool findSegmentForAddr(in ref dl_phdr_info info, in void* addr, ElfW!"Phdr"* result=null) nothrow @nogc
+static if (SharedELF) bool findSegmentForAddr(in ref dl_phdr_info info, in void* addr, ElfW!"Phdr"* result=null) nothrow @nogc
 {
     if (addr < cast(void*)info.dlpi_addr) // less than base address of object means quick reject
         return false;
@@ -845,13 +914,15 @@ bool findSegmentForAddr(in ref dl_phdr_info info, in void* addr, ElfW!"Phdr"* re
 version (linux) import core.sys.linux.errno : program_invocation_name;
 // should be in core.sys.freebsd.stdlib
 version (FreeBSD) extern(C) const(char)* getprogname() nothrow @nogc;
+version (OSX) extern(C) const(char)* getprogname() nothrow @nogc;
 version (DragonFlyBSD) extern(C) const(char)* getprogname() nothrow @nogc;
 version (NetBSD) extern(C) const(char)* getprogname() nothrow @nogc;
 
 @property const(char)* progname() nothrow @nogc
 {
     version (linux) return program_invocation_name;
     version (FreeBSD) return getprogname();
+    version (OSX) return getprogname();
     version (DragonFlyBSD) return getprogname();
     version (NetBSD) return getprogname();
 }
@@ -894,42 +965,58 @@ struct tls_index
     size_t ti_offset;
 }
 
-extern(C) void* __tls_get_addr(tls_index* ti) nothrow @nogc;
+version (OSX)
+{
+    extern(C) void _d_dyld_getTLSRange(void*, void**, size_t*) nothrow @nogc;
 
-/* The dynamic thread vector (DTV) pointers may point 0x8000 past the start of
- * each TLS block. This is at least true for PowerPC and Mips platforms.
- * See: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/powerpc/dl-tls.h;h=f7cf6f96ebfb505abfd2f02be0ad0e833107c0cd;hb=HEAD#l34
- *      https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/mips/dl-tls.h;h=93a6dc050cb144b9f68b96fb3199c60f5b1fcd18;hb=HEAD#l32
- */
-version (X86)
-    enum TLS_DTV_OFFSET = 0x0;
-else version (X86_64)
-    enum TLS_DTV_OFFSET = 0x0;
-else version (ARM)
-    enum TLS_DTV_OFFSET = 0x0;
-else version (AArch64)
-    enum TLS_DTV_OFFSET = 0x0;
-else version (SPARC)
-    enum TLS_DTV_OFFSET = 0x0;
-else version (SPARC64)
-    enum TLS_DTV_OFFSET = 0x0;
-else version (PPC)
-    enum TLS_DTV_OFFSET = 0x8000;
-else version (PPC64)
-    enum TLS_DTV_OFFSET = 0x8000;
-else version (MIPS32)
-    enum TLS_DTV_OFFSET = 0x8000;
-else version (MIPS64)
-    enum TLS_DTV_OFFSET = 0x8000;
+    void[] getTLSRange(void *tlsSymbol) nothrow @nogc
+    {
+        void* start = null;
+        size_t size = 0;
+        _d_dyld_getTLSRange(tlsSymbol, &start, &size);
+        assert(start && size, "Could not determine TLS range.");
+        return start[0 .. size];
+    }
+}
 else
-    static assert( false, "Platform not supported." );
-
-void[] getTLSRange(size_t mod, size_t sz) nothrow @nogc
 {
-    if (mod == 0)
-        return null;
+    extern(C) void* __tls_get_addr(tls_index* ti) nothrow @nogc;
 
-    // base offset
-    auto ti = tls_index(mod, 0);
-    return (__tls_get_addr(&ti)-TLS_DTV_OFFSET)[0 .. sz];
+    /* The dynamic thread vector (DTV) pointers may point 0x8000 past the start of
+     * each TLS block. This is at least true for PowerPC and Mips platforms.
+     * See: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/powerpc/dl-tls.h;h=f7cf6f96ebfb505abfd2f02be0ad0e833107c0cd;hb=HEAD#l34
+     *      https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/mips/dl-tls.h;h=93a6dc050cb144b9f68b96fb3199c60f5b1fcd18;hb=HEAD#l32
+     */
+    version (X86)
+        enum TLS_DTV_OFFSET = 0x0;
+    else version (X86_64)
+        enum TLS_DTV_OFFSET = 0x0;
+    else version (ARM)
+        enum TLS_DTV_OFFSET = 0x0;
+    else version (AArch64)
+        enum TLS_DTV_OFFSET = 0x0;
+    else version (SPARC)
+        enum TLS_DTV_OFFSET = 0x0;
+    else version (SPARC64)
+        enum TLS_DTV_OFFSET = 0x0;
+    else version (PPC)
+        enum TLS_DTV_OFFSET = 0x8000;
+    else version (PPC64)
+        enum TLS_DTV_OFFSET = 0x8000;
+    else version (MIPS32)
+        enum TLS_DTV_OFFSET = 0x8000;
+    else version (MIPS64)
+        enum TLS_DTV_OFFSET = 0x8000;
+    else
+        static assert( false, "Platform not supported." );
+
+    void[] getTLSRange(size_t mod, size_t sz) nothrow @nogc
+    {
+        if (mod == 0)
+            return null;
+
+        // base offset
+        auto ti = tls_index(mod, 0);
+        return (__tls_get_addr(&ti)-TLS_DTV_OFFSET)[0 .. sz];
+    }
 }