partial support for runtime linking of separately-compiled modules (only functions)

3 files changed, 27 insertions, 1 deletions

diff --git a/src/jsifier.js b/src/jsifier.js
index b941032a..feebbe5a 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -321,6 +321,10 @@ function JSify(data, functionsOnly, givenFunctions) {
           if (item.ident in EXPORTED_GLOBALS) {
             js += '\nModule["' + item.ident + '"] = ' + item.ident + ';';
           }
+          // TODO: Support exporting BUILD_AS_SHARED_LIB == 2 globals. The problem now is that they override the main file's globals.
+          //if (BUILD_AS_SHARED_LIB == 2) {
+          //  js += 'if (globalScope) globalScope["' + item.ident + '"] = ' + item.ident + ';'; // XXX: assert not overriding
+          //}
           return ret.concat({
             intertype: 'GlobalVariable',
             JS: js,
@@ -603,6 +607,10 @@ function JSify(data, functionsOnly, givenFunctions) {
         func.JS += func.ident + '["X"]=1;';
       }
 
+      if (BUILD_AS_SHARED_LIB == 2) {
+        func.JS += 'if (globalScope) { assert(!globalScope["' + func.ident + '"]); globalScope["' + func.ident + '"] = ' + func.ident + ' }';
+      }
+
       return func;
     }
   });
@@ -1116,7 +1124,14 @@ function JSify(data, functionsOnly, givenFunctions) {
     data.unparsedGlobalss = null;
 
     print(Functions.generateIndexing()); // done last, as it may rely on aliases set in postsets
+
+    // Load runtime-linked libraries
+    RUNTIME_LINKED_LIBS.forEach(function(lib) {
+      print('eval(read("' + lib + '"))(FUNCTION_TABLE.length, this);');
+    });
+
     print(postParts[1]);
+
     print(shellParts[1]);
     // Print out some useful metadata (for additional optimizations later, like the eliminator)
     print('// EMSCRIPTEN_GENERATED_FUNCTIONS: ' + JSON.stringify(Functions.allIdents) + '\n');
diff --git a/src/settings.js b/src/settings.js
index 66762298..9dba6a24 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -172,6 +172,17 @@ var SHOW_LABELS = 0; // Show labels in the generated code
 
 var BUILD_AS_SHARED_LIB = 0; // Whether to build the code as a shared library, which
                              // must be loaded dynamically using dlopen().
+                             // 0 here means this is not a shared lib: It is a main file.
+                             // 1 means this is a normal shared lib.
+                             // 2 means this is a shared lib that will be linked at runtime,
+                             //   which means it will insert its functions into
+                             //   the global namespace. See STATIC_LIBS_TO_LOAD. Note
+                             //   that only functions are exported, not globals, since
+                             //   in a naive implementation they can easily override main's
+                             //   symbols (for example, the global strings, _str1 etc.).
+var RUNTIME_LINKED_LIBS = []; // If this is a main file (BUILD_AS_SHARED_LIB == 0), then
+                              // we will link these at runtime. They must have been built with
+                              // BUILD_AS_SHARED_LIB == 2.
 
 var RUNTIME_TYPE_INFO = 0; // Whether to expose type info to the script at run time. This
                            // increases the size of the generated script, but allows you
diff --git a/src/shell_sharedlib.js b/src/shell_sharedlib.js
index 60a78323..1d34c73e 100644
--- a/src/shell_sharedlib.js
+++ b/src/shell_sharedlib.js
@@ -1,5 +1,5 @@
 // Capture the output of this into a variable, if you want
-(function(FUNCTION_TABLE_OFFSET) {
+(function(FUNCTION_TABLE_OFFSET, globalScope) {
   var Module = {};
   var args = [];
   Module.arguments = [];