an attempt to fix the otool disassembler

cctools/libstuff/llvm.c

@@ -14,7 +14,11 @@
  * plan to include it (along with the current libLTO APIs) in a generic
  * libLLVM.dylib.
  */
+#ifdef __APPLE__
+#define LIB_LLVM "libLTO.dylib"
+#else
 #define LIB_LLVM "libLTO.so"
+#endif /* __APPLE__ */
 
 static int tried_to_load_llvm = 0;
 static void *llvm_handle = NULL;
@@ -62,12 +66,20 @@ static void load_llvm(void)
 		p[1] = '\0';
 	    llvm_path = makestr(prefix, "../lib/" LIB_LLVM, NULL);
 
+#ifdef __APPLE__
 	    llvm_handle = dlopen(llvm_path, RTLD_NOW);
 	    if(llvm_handle == NULL){
 		free(llvm_path);
 		llvm_path = NULL;
-		llvm_handle = dlopen("/usr/lib/llvm/" LIB_LLVM, RTLD_NOW);
+		llvm_handle = dlopen("/Applications/Xcode.app/Contents/"
+				     "Developer/Toolchains/XcodeDefault."
+				     "xctoolchain/usr/lib/" LIB_LLVM,
+				     RTLD_NOW);
 	    }
+#else
+	    llvm_handle = dlopen(LIB_LLVM, RTLD_NOW);
+#endif /* __APPLE__ */
+
 	    if(llvm_handle == NULL)
 		return;
 
@@ -80,6 +92,13 @@ static void load_llvm(void)
 	    createCPU = dlsym(llvm_handle, "LLVMCreateDisasmCPU");
 	    version = dlsym(llvm_handle, "lto_get_version");
 
+#ifndef __APPLE__
+	    if(create == NULL){
+		fprintf(stderr, "Your " LIB_LLVM " lacks required symbols.\n");
+		fprintf(stderr, "Please run: tools/fix_liblto.sh (or http://git.io/AyZP) to fix libLTO.\n");
+	    }
+#endif /* __APPLE__ */
+
 	    if(create == NULL ||
 	       dispose == NULL ||
 	       disasm == NULL){

tools/fix_liblto.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+## http://llvm.org/PR22677
+
+pushd "${0%/*}" &>/dev/null
+
+if [ $(uname -s) == "Darwin" ]; then
+  echo "Darwin works out of the box."
+  exit 1
+fi
+
+if [ -z "$LLVM_CONFIG" ]; then
+  LLVM_CONFIG=llvm-config
+fi
+
+which $LLVM_CONFIG &>/dev/null
+
+if [ $? -ne 0 ]; then
+  echo -n "Cannot find $LLVM_CONFIG, you may want to try " 1>&2
+  echo "LLVM_CONFIG=llvm-config<suffix> $0" 1>&2
+  exit 1
+fi
+
+LIBDIR=$($LLVM_CONFIG --libdir)
+INCDIR=$($LLVM_CONFIG --includedir)
+
+V="$(readelf -Ws $LIBDIR/libLTO.so 2>/dev/null | grep LLVMCreateDisasm)"
+
+if [ -n "$V" ]; then
+  echo "No fix needed."
+  exit 1
+fi
+
+VERSION=$($LLVM_CONFIG --version | awk -F \. {'print $1$2'} | sed 's/svn//g')
+
+if [ $VERSION -lt 34 ]; then
+  echo "This tool requires LLVM 3.4 or later." 1>&2
+  exit 1
+fi
+
+LIBS=$($LLVM_CONFIG --libs all)
+SYSLIBS=$($LLVM_CONFIG --system-libs 2>/dev/null || echo "-ldl -lz -ltinfo -pthread")
+CXXFLAGS=$($LLVM_CONFIG --cxxflags)
+
+if [ $VERSION -ge 35 ]; then
+  SYSLIBS+=" -ledit"
+fi
+
+set -e
+TMP=$(mktemp -d)
+set +e
+
+pushd $TMP &>/dev/null
+wget https://raw.githubusercontent.com/llvm-mirror/llvm/release_$VERSION/tools/lto/lto.cpp
+wget https://raw.githubusercontent.com/llvm-mirror/llvm/release_$VERSION/tools/lto/LTODisassembler.cpp
+wget https://raw.githubusercontent.com/llvm-mirror/llvm/release_$VERSION/tools/lto/lto.exports
+
+echo "{" > lto.ls
+echo "  global:" >> lto.ls
+while read p; do
+  echo "   $p;" >> lto.ls
+done < lto.exports
+echo "   LLVM*;" >> lto.ls
+echo "  local: *;" >> lto.ls
+echo "};" >> lto.ls
+popd &>/dev/null
+
+set -x
+
+clang++ -shared \
+ -L$LIBDIR -I$INCDIR -Wl,--whole-archive $LIBS -Wl,--no-whole-archive $SYSLIBS \
+ $CXXFLAGS $TMP/lto.cpp $TMP/LTODisassembler.cpp -Wl,-Map,$TMP/lto.exports \
+ -Wl,-no-undefined -fno-rtti -fPIC -o libLTO.so
+
+rm -r $TMP
+
+mv -f libLTO.so $LIBDIR || {
+  set +x
+  echo "Try again as root."
+  echo "Or run the following command by hand: mv $PWD/libLTO.so $LIBDIR"
+  exit 1
+}