Add emcc option "--split <size>" to split javascript file.

Splits the resulting javascript file into pieces to ease debugging.
This option only works if Javascript is generated (target -o <name>.js).

Files with function declarations must be loaded before main file upon execution.

Without "-g" option:
Creates files with function declarations up to the given size with the suffix "_functions.partxxx.js" and a main file with the suffix ".js".

With "-g" option:
Recreates the directory structure of the C source files and stores function declarations in their respective C files with the suffix ".js". If such a file exceeds the given size, files with the suffix ".partxxx.js" are created. The main file resides in the base directory and has the suffix ".js".

3 files changed, 24 insertions, 0 deletions

diff --git a/src/jsifier.js b/src/jsifier.js
index 92b39b7d..8021f8a1 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -522,6 +522,11 @@ function JSify(data, functionsOnly, givenFunctions) {
         func.JS += ' */\n';
       }
 
+      if (PRINT_SPLIT_FILE_MARKER) {
+          func.JS += '\n//FUNCTION_BEGIN_MARKER\n'
+          var associatedSourceFile = "NO_SOURCE";
+      }
+      
       func.JS += 'function ' + func.ident + '(' + paramIdents.join(', ') + ') {\n';
 
       if (PROFILE) {
@@ -572,6 +577,13 @@ function JSify(data, functionsOnly, givenFunctions) {
           if (EXECUTION_TIMEOUT > 0) {
             ret += indent + 'if (Date.now() - START_TIME >= ' + (EXECUTION_TIMEOUT*1000) + ') throw "Timed out!" + (new Error().stack);\n';
           }
+          
+          if (PRINT_SPLIT_FILE_MARKER && Debugging.on && Debugging.getAssociatedSourceFile(line.lineNum)) {
+            // Overwrite the associated source file for every line. The last line should contain the source file associated to
+            // the return value/address of outer most block (the marked function).
+            associatedSourceFile = Debugging.getAssociatedSourceFile(line.lineNum);
+          }
+          
           // for special labels we care about (for phi), mark that we visited them
           return ret + label.lines.map(function(line) { return line.JS + (Debugging.on ? Debugging.getComment(line.lineNum) : '') })
                                   .join('\n')
@@ -653,6 +665,11 @@ function JSify(data, functionsOnly, givenFunctions) {
         func.JS += '  return' + (func.returnType !== 'void' ? ' null' : '') + ';\n';
       }
       func.JS += '}\n';
+      
+      if (PRINT_SPLIT_FILE_MARKER) {
+          func.JS += '\n//FUNCTION_END_MARKER_OF_SOURCE_FILE_' + associatedSourceFile + '\n';
+      }
+      
       if (func.ident in EXPORTED_FUNCTIONS) {
         func.JS += 'Module["' + func.ident + '"] = ' + func.ident + ';';
       }
diff --git a/src/modules.js b/src/modules.js
index 0f3b483b..cf1b072e 100644
--- a/src/modules.js
+++ b/src/modules.js
@@ -127,6 +127,11 @@ var Debugging = {
                                                                 this.llvmLineToSourceFile[lineNum] + '"' : '';
   },
 
+  getAssociatedSourceFile: function(lineNum) {
+    if (!this.on) return null;
+    return lineNum in this.llvmLineToSourceLine ? this.llvmLineToSourceFile[lineNum] : null;
+  },
+  
   getIdentifier: function(lineNum) {
     if (!this.on) return null;
     if (lineNum === undefined) {
diff --git a/src/settings.js b/src/settings.js
index f8a81711..9a1afd69 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -202,6 +202,8 @@ var SHELL_FILE = 0; // set this to a string to override the shell file used
 
 var SHOW_LABELS = 0; // Show labels in the generated code
 
+var PRINT_SPLIT_FILE_MARKER = 0; // Prints markers in Javascript generation to split the file later on. See emcc --split option.
+
 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.