exceptions support in backend itself

3 files changed, 34 insertions, 32 deletions

diff --git a/lib/Target/JSBackend/CallHandlers.h b/lib/Target/JSBackend/CallHandlers.h
index aa4a1a7c93..585ad339a5 100644
--- a/lib/Target/JSBackend/CallHandlers.h
+++ b/lib/Target/JSBackend/CallHandlers.h
@@ -43,8 +43,8 @@ DEF_CALL_HANDLER(__default__, {
   bool NeedCasts;
   FunctionType *FT;
   bool Invoke = false;
-  if (isa<const InvokeInst>(CI)) {
-    // invoke of f(a, b) turns into invoke_sig(index-of-f, a, b)
+  if (InvokeState == 1) {
+    InvokeState = 2;
     Invoke = true;
   }
   std::string Sig;
@@ -101,6 +101,28 @@ DEF_CALL_HANDLER(__default__, {
   return text;
 })
 
+// exceptions support
+DEF_CALL_HANDLER(emscripten_preinvoke, {
+  assert(InvokeState == 0);
+  InvokeState = 1;
+  return "__THREW__ = 0";
+})
+DEF_CALL_HANDLER(emscripten_postinvoke, {
+  assert(InvokeState == 2);
+  InvokeState = 0;
+  return getAssign(getJSName(CI), CI->getType()) + "__THREW__";
+})
+DEF_CALL_HANDLER(emscripten_landingpad, {
+  std::string Ret = getAssign(getJSName(CI), CI->getType()) + "___cxa_find_matching_catch(-1,-1";
+  unsigned Num = getNumArgOperands(CI);
+  for (unsigned i = 1; i < Num-1; i++) { // ignore personality and cleanup XXX - we probably should not be doing that!
+    Ret += ",";
+    Ret += getValueAsStr(CI->getOperand(i));
+  }
+  Ret += ")|0";
+  return Ret;
+})
+
 DEF_CALL_HANDLER(getHigh32, {
   return getAssign(getJSName(CI), CI->getType()) + "tempRet0";
 })
@@ -547,6 +569,9 @@ void setupCallHandlers() {
     (*CallHandlers)[std::string("_") + #Ident] = &JSWriter::CH_##Ident;
 
   SETUP_CALL_HANDLER(__default__);
+  SETUP_CALL_HANDLER(emscripten_preinvoke);
+  SETUP_CALL_HANDLER(emscripten_postinvoke);
+  SETUP_CALL_HANDLER(emscripten_landingpad);
   SETUP_CALL_HANDLER(getHigh32);
   SETUP_CALL_HANDLER(setHigh32);
   SETUP_CALL_HANDLER(FPtoILow);
diff --git a/lib/Target/JSBackend/JSBackend.cpp b/lib/Target/JSBackend/JSBackend.cpp
index 098b86915f..617f33b011 100644
--- a/lib/Target/JSBackend/JSBackend.cpp
+++ b/lib/Target/JSBackend/JSBackend.cpp
@@ -103,12 +103,13 @@ namespace {
     FunctionTableMap FunctionTables; // sig => list of functions
     std::vector<std::string> GlobalInitializers;
     bool UsesSIMD;
+    int InvokeState; // cycles between 0, 1 after preInvoke, 2 after call, 0 again after postInvoke. hackish, no argument there.
 
     #include "CallHandlers.h"
 
   public:
     static char ID;
-    explicit JSWriter(formatted_raw_ostream &o) : ModulePass(ID), Out(o), UniqueNum(0), UsesSIMD(false) {}
+    explicit JSWriter(formatted_raw_ostream &o) : ModulePass(ID), Out(o), UniqueNum(0), UsesSIMD(false), InvokeState(0) {}
 
     virtual const char *getPassName() const { return "JavaScript backend"; }
 
@@ -1238,24 +1239,6 @@ void JSWriter::generateInstruction(const Instruction *I, raw_string_ostream& Cod
     Code << ";";
     break;
   }
-  case Instruction::Invoke: {
-    Code << "__THREW__ = 0;";
-    const InvokeInst *II = cast<InvokeInst>(I);
-    Code << handleCall(II) + ';';
-    // the check and branch and done in the relooper setup code
-    break;
-  }
-  case Instruction::LandingPad: {
-    const LandingPadInst *LP = cast<const LandingPadInst>(I);
-    Code << getAssign(iName, I->getType());
-    Code << "___cxa_find_matching_catch(-1,-1";
-    unsigned n = LP->getNumClauses();
-    for (unsigned i = 0; i < n; i++) {
-      Code << "," + getValueAsStr(LP->getClause(i));
-    }
-    Code << ")|0;";
-    break;
-  }
   case Instruction::Resume: {
     Code << "___resumeException(" + getValueAsStr(I->getOperand(0)) + "|0);";
     break;
@@ -1380,16 +1363,6 @@ void JSWriter::printFunctionBody(const Function *F) {
         }
         break;
       }
-      case Instruction::Invoke: {
-        const InvokeInst* II = cast<InvokeInst>(TI);
-        BasicBlock *S0 = II->getNormalDest();
-        BasicBlock *S1 = II->getUnwindDest();
-        std::string P0 = getPhiCode(&*BI, S0);
-        std::string P1 = getPhiCode(&*BI, S1);
-        LLVMToRelooper[&*BI]->AddBranchTo(LLVMToRelooper[&*S0], "!__THREW__", P0.size() > 0 ? P0.c_str() : NULL);
-        LLVMToRelooper[&*BI]->AddBranchTo(LLVMToRelooper[&*S1], NULL,         P1.size() > 0 ? P1.c_str() : NULL);
-        break;
-      }
       case Instruction::Ret:
       case Instruction::Unreachable: break;
     }
diff --git a/lib/Transforms/NaCl/LowerEmExceptionsPass.cpp b/lib/Transforms/NaCl/LowerEmExceptionsPass.cpp
index fdf78bf6eb..18afc46c68 100644
--- a/lib/Transforms/NaCl/LowerEmExceptionsPass.cpp
+++ b/lib/Transforms/NaCl/LowerEmExceptionsPass.cpp
@@ -17,6 +17,10 @@
 //         threw = postinvoke(); (check __THREW__)
 //         br threw, l1, l2
 //
+//     We do this to avoid introducing a new LLVM IR type, or to try to reuse
+//     invoke-landingpad for our special purposes (as they are checked very
+//     carefully by llvm)
+//
 //  2) Lower landingpads to return a single i8*, avoid the structural type
 //     which is unneeded anyhow.
 //
@@ -127,7 +131,7 @@ bool LowerEmExceptions::runOnModule(Module &M) {
         CallInst *Post = CallInst::Create(PostInvoke, "", II);
 
         // Insert a branch based on the postInvoke
-        BranchInst::Create(II->getNormalDest(), II->getUnwindDest(), Post, II);
+        BranchInst::Create(II->getUnwindDest(), II->getNormalDest(), Post, II);
 
         // Replace the landingpad with a landingpad call to get the low part, and a getHigh for the high
         LandingPadInst *LP = II->getLandingPadInst();