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mach_o/SplitSeg.cpp /dev/null dyld-1162
--- /dev/null
+++ dyld/dyld-1162/mach_o/SplitSeg.cpp
@@ -0,0 +1,218 @@
+/*
+ * Copyright (c) 2017 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 <stdio.h>
+#include <string.h>
+
+#include "SplitSeg.h"
+#include "Misc.h"
+
+#if BUILDING_MACHO_WRITER
+#include <map>
+#endif
+
+// FIXME: We should get this from cctools
+#define DYLD_CACHE_ADJ_V2_FORMAT 0x7F
+
+namespace mach_o {
+
+SplitSegInfo::SplitSegInfo(const uint8_t* start, size_t size)
+: _infoStart(start), _infoEnd(start + size)
+{
+}
+
+Error SplitSegInfo::valid() const
+{
+    return Error::none();
+}
+
+bool SplitSegInfo::isV1() const
+{
+    return !this->isV2();
+}
+
+bool SplitSegInfo::isV2() const
+{
+    return (*_infoStart == DYLD_CACHE_ADJ_V2_FORMAT);
+}
+
+Error SplitSegInfo::forEachReferenceV2(void (^callback)(const Entry& entry, bool& stop)) const
+{
+    const uint8_t* infoStart = this->_infoStart;
+    const uint8_t* infoEnd = this->_infoEnd;
+
+    if ( *infoStart++ != DYLD_CACHE_ADJ_V2_FORMAT ) {
+        return Error("Not split seg v2");
+    }
+
+    // Whole         :== <count> FromToSection+
+    // FromToSection :== <from-sect-index> <to-sect-index> <count> ToOffset+
+    // ToOffset         :== <to-sect-offset-delta> <count> FromOffset+
+    // FromOffset     :== <kind> <count> <from-sect-offset-delta>
+    const uint8_t* p = infoStart;
+    bool malformed = false;
+    uint64_t sectionCount = read_uleb128(p, infoEnd, malformed);
+    if ( malformed )
+        return Error("malformed uleb128");
+    for (uint64_t i=0; i < sectionCount; ++i) {
+        uint64_t fromSectionIndex = read_uleb128(p, infoEnd, malformed);
+        if ( malformed )
+            return Error("malformed uleb128");
+        uint64_t toSectionIndex = read_uleb128(p, infoEnd, malformed);
+        if ( malformed )
+            return Error("malformed uleb128");
+        uint64_t toOffsetCount = read_uleb128(p, infoEnd, malformed);
+        if ( malformed )
+            return Error("malformed uleb128");
+        uint64_t toSectionOffset = 0;
+        for (uint64_t j=0; j < toOffsetCount; ++j) {
+            uint64_t toSectionDelta = read_uleb128(p, infoEnd, malformed);
+            if ( malformed )
+                return Error("malformed uleb128");
+            uint64_t fromOffsetCount = read_uleb128(p, infoEnd, malformed);
+            if ( malformed )
+                return Error("malformed uleb128");
+            toSectionOffset += toSectionDelta;
+            for (uint64_t k=0; k < fromOffsetCount; ++k) {
+                uint64_t kind = read_uleb128(p, infoEnd, malformed);
+                if ( malformed )
+                    return Error("malformed uleb128");
+                if ( kind > 13 ) {
+                    return Error("bad kind (%llu) value\n", kind);
+                }
+                uint64_t fromSectDeltaCount = read_uleb128(p, infoEnd, malformed);
+                if ( malformed )
+                    return Error("malformed uleb128");
+                uint64_t fromSectionOffset = 0;
+                for (uint64_t l=0; l < fromSectDeltaCount; ++l) {
+                    uint64_t delta = read_uleb128(p, infoEnd, malformed);
+                    if ( malformed )
+                        return Error("malformed uleb128");
+                    fromSectionOffset += delta;
+                    bool stop = false;
+                    callback(Entry { (uint8_t)kind, fromSectionIndex, fromSectionOffset, toSectionIndex, toSectionOffset }, stop);
+                    if ( stop )
+                        return Error::none();
+                }
+            }
+        }
+    }
+
+    return Error::none();
+}
+
+#if BUILDING_MACHO_WRITER
+
+static void append_uleb128(uint64_t value, std::vector<uint8_t>& out)
+{
+    uint8_t byte;
+    do {
+        byte = value & 0x7F;
+        value &= ~0x7F;
+        if ( value != 0 )
+            byte |= 0x80;
+        out.push_back(byte);
+        value = value >> 7;
+    } while ( byte >= 0x80 );
+}
+
+SplitSegInfo::SplitSegInfo(std::span<const Entry> entries)
+{
+    // Whole         :== <count> FromToSection+
+    // FromToSection :== <from-sect-index> <to-sect-index> <count> ToOffset+
+    // ToOffset         :== <to-sect-offset-delta> <count> FromOffset+
+    // FromOffset     :== <kind> <count> <from-sect-offset-delta>
+
+    typedef uint32_t SectionIndexes;
+    typedef std::map<uint8_t, std::vector<uint64_t> > FromOffsetMap;
+    typedef std::map<uint64_t, FromOffsetMap> ToOffsetMap;
+    typedef std::map<SectionIndexes, ToOffsetMap> WholeMap;
+
+    // sort into group by adjustment kind
+    //fprintf(stderr, "_splitSegV2Infos.size=%lu\n", this->_writer._splitSegV2Infos.size());
+    WholeMap whole;
+    for ( const Entry& entry : entries ) {
+        //fprintf(stderr, "from=%d, to=%d\n", entry.fromSectionIndex, entry.toSectionIndex);
+        SectionIndexes index = (uint32_t)entry.fromSectionIndex << 16 | (uint32_t)entry.toSectionIndex;
+        ToOffsetMap& toOffsets = whole[index];
+        FromOffsetMap& fromOffsets = toOffsets[entry.toSectionOffset];
+        fromOffsets[entry.kind].push_back(entry.fromSectionOffset);
+    }
+
+    // Add marker that this is V2 data
+    this->_bytes.reserve(8192);
+    this->_bytes.push_back(DYLD_CACHE_ADJ_V2_FORMAT);
+
+    // stream out
+    // Whole :== <count> FromToSection+
+    append_uleb128(whole.size(), this->_bytes);
+    for (auto& fromToSection : whole) {
+        uint8_t fromSectionIndex = fromToSection.first >> 16;
+        uint8_t toSectionIndex   = fromToSection.first & 0xFFFF;
+        ToOffsetMap& toOffsets   = fromToSection.second;
+        // FromToSection :== <from-sect-index> <to-sect-index> <count> ToOffset+
+        append_uleb128(fromSectionIndex, this->_bytes);
+        append_uleb128(toSectionIndex, this->_bytes);
+        append_uleb128(toOffsets.size(), this->_bytes);
+        //fprintf(stderr, "from sect=%d, to sect=%d, count=%lu\n", fromSectionIndex, toSectionIndex, toOffsets.size());
+        uint64_t lastToOffset = 0;
+        for (auto& fromToOffsets : toOffsets) {
+            uint64_t toSectionOffset = fromToOffsets.first;
+            FromOffsetMap& fromOffsets = fromToOffsets.second;
+            // ToOffset    :== <to-sect-offset-delta> <count> FromOffset+
+            append_uleb128(toSectionOffset - lastToOffset, this->_bytes);
+            append_uleb128(fromOffsets.size(), this->_bytes);
+            for (auto& kindAndOffsets : fromOffsets) {
+                uint8_t kind = kindAndOffsets.first;
+                std::vector<uint64_t>& fromSectOffsets = kindAndOffsets.second;
+                // FromOffset :== <kind> <count> <from-sect-offset-delta>
+                append_uleb128(kind, this->_bytes);
+                append_uleb128(fromSectOffsets.size(), this->_bytes);
+                std::sort(fromSectOffsets.begin(), fromSectOffsets.end());
+                uint64_t lastFromOffset = 0;
+                for (uint64_t offset : fromSectOffsets) {
+                    append_uleb128(offset - lastFromOffset, this->_bytes);
+                    lastFromOffset = offset;
+                }
+            }
+            lastToOffset = toSectionOffset;
+        }
+    }
+
+
+    // always add zero byte to mark end
+    this->_bytes.push_back(0);
+
+    // pad to be 8-btye aligned
+    while ( (this->_bytes.size() % 8) != 0 )
+        this->_bytes.push_back(0);
+
+    // set up buffer
+    this->_infoStart = &this->_bytes.front();
+    this->_infoEnd   = &this->_bytes.back();
+}
+
+#endif // BUILDING_MACHO_WRITER
+
+} // namepace mach_o