Support Emscripten EH/SjLj in Wasm64

src/library.js

@@ -1521,30 +1521,11 @@ LibraryManager.library = {
   gnu_dev_minor: 'minor',
 
   // ==========================================================================
-  // setjmp.h
+  // setjmp / longjmp support
   // ==========================================================================
 
-  longjmp__sig: 'vii',
-#if SUPPORT_LONGJMP
-  longjmp: function(env, value) {
-    _setThrew(env, value || 1);
-    throw 'longjmp';
-  },
-#else
-  longjmp__deps: [function() {
-    error('longjmp support was disabled (SUPPORT_LONGJMP=0), but it is required by the code (either set SUPPORT_LONGJMP=1, or remove uses of it in the project)');
-  }],
-  // will never be emitted, as the dep errors at compile time
-  longjmp: function(env, value) {
-    abort('longjmp not supported');
-  },
-#endif
-  // TODO: remove these aliases if/when the LLVM backend can stop emitting them
-  // (it emits them atm as they are generated by an IR pass, at at that time
-  // they each have a different signature - it is only at the wasm level that
-  // they become identical).
-  emscripten_longjmp__sig: 'vii',
-  emscripten_longjmp: 'longjmp',
+  _emscripten_throw_longjmp__sig: 'v',
+  _emscripten_throw_longjmp: function() { throw 'longjmp'; },
 
   // ==========================================================================
   // sys/wait.h

system/lib/compiler-rt/emscripten_exception_builtins.c

@@ -11,10 +11,10 @@
 
 #include <threads.h>
 
-thread_local int __THREW__ = 0;
+thread_local uintptr_t __THREW__ = 0;
 thread_local int __threwValue = 0;
 
-void setThrew(int threw, int value) {
+void setThrew(uintptr_t threw, int value) {
   if (__THREW__ == 0) {
     __THREW__ = threw;
     __threwValue = value;

system/lib/compiler-rt/emscripten_setjmp.c

@@ -9,15 +9,19 @@
 #include <stdlib.h>
 #include <setjmp.h>
 
-static uint32_t setjmpId = 0;
+// 0 - Nothing thrown
+// 1 - Exception thrown
+// Other values - jmpbuf pointer in the case that longjmp was thrown
+static uintptr_t setjmpId = 0;
 
 typedef struct TableEntry {
-  uint32_t id, label;
+  uintptr_t id;
+  uint32_t label;
 } TableEntry;
 
 extern void setTempRet0(uint32_t value);
 
-TableEntry* saveSetjmp(uint32_t* env, uint32_t label, TableEntry* table, uint32_t size) {
+TableEntry* saveSetjmp(uintptr_t* env, uint32_t label, TableEntry* table, uint32_t size) {
   // Not particularly fast: slow table lookup of setjmpId to label. But setjmp
   // prevents relooping anyhow, so slowness is to be expected. And typical case
   // is 1 setjmp per invocation, or less.
@@ -43,10 +47,10 @@ TableEntry* saveSetjmp(uint32_t* env, uint32_t label, TableEntry* table, uint32_
   return table;
 }
 
-uint32_t testSetjmp(uint32_t id, TableEntry* table, uint32_t size) {
-  uint32_t i = 0, curr;
+uint32_t testSetjmp(uintptr_t id, TableEntry* table, uint32_t size) {
+  uint32_t i = 0;
   while (i < size) {
-    uint32_t curr = table[i].id;
+    uintptr_t curr = table[i].id;
     if (curr == 0) break;
     if (curr == id) {
       return table[i].label;
@@ -55,3 +59,8 @@ uint32_t testSetjmp(uint32_t id, TableEntry* table, uint32_t size) {
   }
   return 0;
 }
+
+void emscripten_longjmp(uintptr_t env, int val) {
+  setThrew(env, val || 1);
+  emscripten_throw_longjmp();
+}