[mach-o] Fix lazy binding offsets

The way lazy binding works in mach-o is that the linker generates a helper
function and has the stub (PLT) initially jump to it.  The helper function
pushes an extra parameter then jumps into dyld.  The extra parameter is an
offset into the lazy binding info where dyld will find the information about
which symbol to bind and way lazy binding pointer to update.

llvm-svn: 221654

1 files changed, 11 insertions, 2 deletions

diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
index 543b60fe8bc..102b185df52 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
@@ -125,6 +125,12 @@ private:
     void append_uleb128(uint64_t value) {
       llvm::encodeULEB128(value, _ostream);
     }
+    void append_uleb128Fixed(uint64_t value, unsigned byteCount) {
+      unsigned min = llvm::getULEB128Size(value);
+      assert(min <= byteCount);
+      unsigned pad = byteCount - min;
+      llvm::encodeULEB128(value, _ostream, pad);
+    }
     void append_sleb128(int64_t value) {
       llvm::encodeSLEB128(value, _ostream);
     }
@@ -999,6 +1005,7 @@ void MachOFileLayout::buildRebaseInfo() {
 
 void MachOFileLayout::buildBindInfo() {
   // TODO: compress bind info.
+  uint64_t lastAddend = 0;
   for (const BindLocation& entry : _file.bindingInfo) {
     _bindingInfo.append_byte(BIND_OPCODE_SET_TYPE_IMM | entry.kind);
     _bindingInfo.append_byte(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB
@@ -1007,9 +1014,10 @@ void MachOFileLayout::buildBindInfo() {
     _bindingInfo.append_byte(BIND_OPCODE_SET_DYLIB_ORDINAL_IMM | entry.ordinal);
     _bindingInfo.append_byte(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM);
     _bindingInfo.append_string(entry.symbolName);
-    if (entry.addend != 0) {
+    if (entry.addend != lastAddend) {
       _bindingInfo.append_byte(BIND_OPCODE_SET_ADDEND_SLEB);
       _bindingInfo.append_sleb128(entry.addend);
+      lastAddend = entry.addend;
     }
     _bindingInfo.append_byte(BIND_OPCODE_DO_BIND);
   }
@@ -1022,11 +1030,12 @@ void MachOFileLayout::buildLazyBindInfo() {
     _lazyBindingInfo.append_byte(BIND_OPCODE_SET_TYPE_IMM | entry.kind);
     _lazyBindingInfo.append_byte(BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB
                             | entry.segIndex);
-    _lazyBindingInfo.append_uleb128(entry.segOffset);
+    _lazyBindingInfo.append_uleb128Fixed(entry.segOffset, 5);
     _lazyBindingInfo.append_byte(BIND_OPCODE_SET_DYLIB_ORDINAL_IMM | entry.ordinal);
     _lazyBindingInfo.append_byte(BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM);
     _lazyBindingInfo.append_string(entry.symbolName);
     _lazyBindingInfo.append_byte(BIND_OPCODE_DO_BIND);
+    _lazyBindingInfo.append_byte(BIND_OPCODE_DONE);
   }
   _lazyBindingInfo.append_byte(BIND_OPCODE_DONE);
   _lazyBindingInfo.align(_is64 ? 8 : 4);