Added -shared switch.

If the flag is passed, ldc will create a shared library not an executable file.

dmd/mars.h

@@ -271,6 +271,7 @@ struct Global
     char *bc_ext;
     char *s_ext;
     const char *lib_ext;
+    const char *dll_ext;
     const char *doc_ext;        // for Ddoc generated files
     const char *ddoc_ext;       // for Ddoc macro include files
     const char *hdr_ext;        // for D 'header' import files

dmd2/mars.c

@@ -72,10 +72,7 @@ Global::Global()
     s_ext   = "s";
     obj_ext = "o";
 #if _WIN32
-    lib_ext  = "lib";
     obj_ext_alt = "obj";
-#else
-    lib_ext  = "a";
 #endif
 #else
 #if TARGET_WINDOS

gen/cl_options.cpp

@@ -43,6 +43,10 @@ cl::opt<bool> createStaticLib("lib",
     cl::desc("Create static library"),
     cl::ZeroOrMore);
 
+cl::opt<bool> createSharedLib("shared",
+    cl::desc("Create sharedlibrary"),
+    cl::ZeroOrMore);
+
 static cl::opt<bool, true> verbose("v",
     cl::desc("Verbose"),
     cl::ZeroOrMore,

gen/cl_options.h

@@ -20,6 +20,7 @@ namespace opts {
     extern cl::list<std::string> runargs;
     extern cl::opt<bool> compileOnly;
     extern cl::opt<bool> createStaticLib;
+    extern cl::opt<bool> createSharedLib;
     extern cl::opt<bool> noAsm;
     extern cl::opt<bool> dontWriteObj;
     extern cl::opt<std::string> objectFile;

gen/linker.cpp

@@ -28,6 +28,11 @@ llvm::cl::opt<bool> quiet("quiet",
 
 //////////////////////////////////////////////////////////////////////////////
 
+bool endsWith(const std::string &str, const std::string &end)
+{
+    return (str.length() >= end.length() && std::equal(end.rbegin(), end.rend(), str.rbegin()));
+}
+
 typedef std::vector<llvm::Module*> Module_vector;
 
 void linkModules(llvm::Module* dst, const Module_vector& MV)
@@ -213,7 +218,7 @@ int linkExecutable(const char* argv0)
 
 //////////////////////////////////////////////////////////////////////////////
 
-int linkObjToExecutable(const char* argv0)
+int linkObjToBinary(bool sharedLib)
 {
     Logger::println("*** Linking executable ***");
 
@@ -239,29 +244,45 @@ int linkObjToExecutable(const char* argv0)
     }
 
     // output filename
-    std::string exestr;
-    if (global.params.exefile)
+    std::string output;
+    if (!sharedLib && global.params.exefile)
     {   // explicit
-        exestr = global.params.exefile;
+        output = global.params.exefile;
+    }
+    else if (sharedLib && global.params.objname)
+    {   // explicit
+        output = global.params.objname;
     }
     else
     {   // inferred
         // try root module name
         if (Module::rootModule)
-            exestr = Module::rootModule->toChars();
+            output = Module::rootModule->toChars();
         else if (global.params.objfiles->dim)
-            exestr = FileName::removeExt((char*)global.params.objfiles->data[0]);
+            output = FileName::removeExt((char*)global.params.objfiles->data[0]);
         else
-            exestr = "a.out";
+            output = "a.out";
+    }
+
+    if (sharedLib) {
+        std::string libExt = std::string(".") + global.dll_ext;
+        if (!endsWith(output, libExt))
+        {
+            if (global.params.os != OSWindows)
+                output = "lib" + output + libExt;
+            else
+                output.append(libExt);
+        }
+        args.push_back("-shared");
+    } else if (global.params.os == OSWindows && !endsWith(output, ".exe")) {
+        output.append(".exe");
     }
-    if (global.params.os == OSWindows && !(exestr.rfind(".exe") == exestr.length()-4))
-        exestr.append(".exe");
 
     args.push_back("-o");
-    args.push_back(exestr.c_str());
+    args.push_back(output.c_str());
 
     // set the global gExePath
-    gExePath.set(exestr);
+    gExePath.set(output);
     assert(gExePath.isValid());
 
     // create path to exe
@@ -390,13 +411,15 @@ void createStaticLibrary()
         else if (global.params.objfiles->dim)
             libName = FileName::removeExt((char*)global.params.objfiles->data[0]);
         else
-            libName = "a";
+            libName = "a.out";
     }
     std::string libExt = std::string(".") + global.lib_ext;
-    if (libExt.length() > libName.length() ||
-        !std::equal(libExt.rbegin(), libExt.rend(), libName.rbegin()))
+    if (!endsWith(libName, libExt))
     {
-        libName.append(libExt);
+        if (global.params.os != OSWindows)
+            libName = "lib" + libName + libExt;
+        else
+            libName.append(libExt);
     }
     args.push_back(libName.c_str());
 

gen/linker.h

@@ -30,7 +30,7 @@ int linkExecutable(const char* argv0);
  * @param argv0 the argv[0] value as passed to main
  * @return 0 on success.
  */
-int linkObjToExecutable(const char* argv0);
+int linkObjToBinary(bool sharedLib);
 
 /**
  * Create a static library from object files.

gen/main.cpp

@@ -391,7 +391,13 @@ int main(int argc, char** argv)
     if (!global.params.obj || !global.params.output_o || createStaticLib)
         global.params.link = 0;
 
-    if (global.params.link)
+    if (createStaticLib && createSharedLib)
+        error("-lib and -shared switches cannot be used together");
+
+    if (createSharedLib && mRelocModel == llvm::Reloc::Default)
+        mRelocModel = llvm::Reloc::PIC_;
+
+    if (global.params.link && !createSharedLib)
     {
         global.params.exefile = global.params.objname;
         if (files.dim > 1)
@@ -649,6 +655,14 @@ LDC_TARGETS
         fatal();
     }
 
+    if (global.params.os == OSWindows) {
+        global.dll_ext = "dll";
+        global.lib_ext = "lib";
+    } else {
+        global.dll_ext = "so";
+        global.lib_ext = "a";
+    }
+
     // added in 1.039
     if (global.params.doDocComments)
         VersionCondition::addPredefinedGlobalIdent("D_Ddoc");
@@ -1034,7 +1048,7 @@ LDC_TARGETS
     else
     {
         if (global.params.link)
-            status = linkObjToExecutable(global.params.argv0);
+            status = linkObjToBinary(createSharedLib);
         else if (createStaticLib)
             createStaticLibrary();