[llvm-commits] [llvm-gcc-4-2] r39806 - /llvm-gcc-4-2/trunk/gcc/llvm-convert.cpp

[Duncan Sands]

Author: baldrick
Date: Fri Jul 13 07:12:16 2007
New Revision: 39806

URL: http://llvm.org/viewvc/llvm-project?rev=39806&view=rev
Log:
Forward port of [129234].

exception handling tweaks from Duncan:

(1) Fix some comments.
(2) Correct off-by-one in test for branching within the same scope
(currently it never triggers, but comes out in the wash later).
(3) Have all branches to the same destination share cleanup code,
not just exception unwinding branches.  Currently each non-unwind
branch (like falling through at the end of a try scope) gets its
own copy of cleanups.  Change inspired by the thought that the
optimizers find it easy to duplicate blocks, but hard to merge them.
(4) Add a missing bitcast in a rare case.

Modified:
    llvm-gcc-4-2/trunk/gcc/llvm-convert.cpp

Modified: llvm-gcc-4-2/trunk/gcc/llvm-convert.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm-gcc-4-2/trunk/gcc/llvm-convert.cpp?rev=39806&r1=39805&r2=39806&view=diff

==============================================================================
--- llvm-gcc-4-2/trunk/gcc/llvm-convert.cpp (original)
+++ llvm-gcc-4-2/trunk/gcc/llvm-convert.cpp Fri Jul 13 07:12:16 2007
@@ -1320,21 +1320,14 @@
 /// exception edge (as indicated by IsExceptionEdge) these are expanded,
 /// otherwise not.
 ///
-/// Note that it is illegal for inserted cleanups to throw any exceptions,
-/// as indicated by isExceptionEdge.  This is an important case for
-/// exception handling: when unwinding the stack due to an active exception, any
-/// destructors which propagate exceptions should cause terminate to be called.
-/// Thus, if a cleanup does throw an exception, its exception destination must
-/// go to a designated terminate block.
-///
 /// Note that all calling code should emit a new basic block after this, so that
 /// future code does not fall after the terminator.
 ///
 void TreeToLLVM::EmitBranchInternal(BasicBlock *Dest, bool IsExceptionEdge) {
   // Insert the branch.
   BranchInst *BI = Builder.CreateBr(Dest);
-  
-  // If there are no current exception scopes, this edge *couldn't* need 
+
+  // If there are no current exception scopes, this edge *couldn't* need
   // cleanups.  It is not possible to jump into a scope that requires a cleanup.
   // This keeps the C case fast.
   if (CurrentEHScopes.empty()) return;
@@ -1344,11 +1337,10 @@
   if (Dest->getParent()) {
     // This is a forward reference to a block.  Since we know that we can't jump
     // INTO a region that has cleanups, we can only be branching out.
-    //
     std::map<BasicBlock*, unsigned>::iterator I = BlockEHScope.find(Dest);
-    if (I != BlockEHScope.end() && I->second == CurrentEHScopes.size())
+    if (I != BlockEHScope.end() && I->second == CurrentEHScopes.size() - 1)
       return;  // Branch within the same EH scope.
-    
+
     assert((I == BlockEHScope.end() || I->second < CurrentEHScopes.size()) &&
            "Invalid branch into EH region");
   }
@@ -1361,12 +1353,12 @@
 /// that works.
 void TreeToLLVM::AddBranchFixup(BranchInst *BI, bool isExceptionEdge) {
   BasicBlock *Dest = BI->getSuccessor(0);
-  
+
   // Check to see if we already have a fixup for this destination.
   std::vector<BranchFixup> &BranchFixups = CurrentEHScopes.back().BranchFixups;
   for (unsigned i = 0, e = BranchFixups.size(); i != e; ++i)
     if (BranchFixups[i].SrcBranch->getSuccessor(0) == Dest &&
-        BranchFixups[i].isExceptionEdge) {
+        BranchFixups[i].isExceptionEdge == isExceptionEdge) {
       BranchFixup &Fixup = BranchFixups[i];
       // We found a fixup for this destination already.  Recycle it.
       if (&Fixup.SrcBranch->getParent()->front() == Fixup.SrcBranch) {
@@ -2212,11 +2204,11 @@
     FinallyStack.pop_back();
 
     // Because we can emit the same cleanup in more than one context, we must
-    // strip off LLVM information from the decls in the code.  Otherwise, the
-    // we will try to insert the same label into multiple places in the code.
+    // strip off LLVM information from the decls in the code.  Otherwise, we
+    // will try to insert the same label into multiple places in the code.
     StripLLVMTranslation(CleanupCode);
-     
-    
+
+
     // Catches will supply own terminator.
     if (!Builder.GetInsertBlock()->getTerminator()) {
       // Emit a branch to the new target.
@@ -2284,6 +2276,7 @@
     tree TypeInfoNopExpr = (*lang_eh_runtime_type)(Types);
     // Produce value.  Duplicate typeinfo get folded here.
     Value *TypeInfo = Emit(TypeInfoNopExpr, 0);
+    TypeInfo = BitCastToType(TypeInfo, PointerType::get(Type::Int8Ty));
 
     // Call get eh type id.
     Value *TypeID = Builder.CreateCall(FuncEHGetTypeID, &TypeInfo, 1,