DISABLE_EXCEPTIONS option

2 files changed, 13 insertions, 2 deletions

diff --git a/src/jsifier.js b/src/jsifier.js
index 9ca0047f..078e57ea 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -685,12 +685,15 @@ function JSify(data, functionsOnly, givenFunctions, givenGlobalVariables) {
   makeFuncLineActor('invoke', function(item) {
     // Wrapping in a function lets us easily return values if we are
     // in an assignment
+    var call_ = makeFunctionCall(item.ident, item.params, item.funcData);
+    var branch = makeBranch(item.toLabel, item.currLabelId);
+    if (DISABLE_EXCEPTIONS) return call_ + '; ' + branch;
     var ret = '(function() { try { __THREW__ = false; return '
-            + makeFunctionCall(item.ident, item.params, item.funcData) + ' '
+            + call_ + ' '
             + '} catch(e) { '
             + 'if (ABORT) throw e; __THREW__ = true; '
             + (EXCEPTION_DEBUG ? 'print("Exception: " + e + ", currently at: " + (new Error().stack)); ' : '')
-            + 'return null } })(); if (!__THREW__) { ' + makeBranch(item.toLabel, item.currLabelId)
+            + 'return null } })(); if (!__THREW__) { ' + branch
             + ' } else { ' + makeBranch(item.unwindLabel, item.currLabelId) + ' }';
     return ret;
   });
diff --git a/src/settings.js b/src/settings.js
index 226c30b2..ed3437b1 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -63,6 +63,14 @@ SAFE_HEAP_LOG = 0; // Log out all SAFE_HEAP operations
 
 LABEL_DEBUG = 0; // Print out labels and functions as we enter them
 EXCEPTION_DEBUG = 1; // Print out exceptions in emscriptened code
+DISABLE_EXCEPTIONS = 0; // Disables generating code to actually catch exceptions. If the code you
+                        // are compiling does not actually rely on catching exceptions (but the
+                        // compiler generates code for it, maybe because of stdlibc++ stuff),
+                        // then this can make it much faster. If an exception actually happens,
+                        // it will not be caught and the program will halt (so this will not
+                        // introduce silent failures, which is good).
+                        // TODO: Make this also remove cxa_begin_catch etc., optimize relooper
+                        //       for it, etc. (perhaps do all of this as preprocessing on .ll?)
 EXECUTION_TIMEOUT = -1; // Throw an exception after X seconds - useful to debug infinite loops
 CHECK_OVERFLOWS = 0; // Add code that checks for overflows in integer math operations.
                      // There is currently not much to do to handle overflows if they occur.