From: Bill Wendling <isanbard@gmail.com>
Date: Thu, 12 Nov 2009 20:51:53 +0000 (+0000)
Subject: If there's more than one function operand to a call instruction, be conservative
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ac18929801f1789d3f735733011541b19a205196;p=oota-llvm.git

If there's more than one function operand to a call instruction, be conservative
and don't assume that the call doesn't throw. It would be nice if there were a
way to determine which is the callee and which is a parameter. In practice, the
architecture we care about normally only have one operand for a call instruction
(x86 and arm).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@87023 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/AsmPrinter/DwarfException.cpp b/lib/CodeGen/AsmPrinter/DwarfException.cpp
index 693dcc2466d..1ef34b96e0e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfException.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfException.cpp
@@ -494,14 +494,25 @@ ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
           // Don't mark a call as potentially throwing if the function it's
           // calling is marked "nounwind".
           bool DoesNotThrow = false;
+          bool SawFunc = false;
           for (unsigned OI = 0, OE = MI->getNumOperands(); OI != OE; ++OI) {
             const MachineOperand &MO = MI->getOperand(OI);
 
             if (MO.isGlobal()) {
               if (Function *F = dyn_cast<Function>(MO.getGlobal())) {
+                if (SawFunc) {
+                  // Be conservative. If we have more than one function operand
+                  // for this call, then we can't make the assumption that it's
+                  // the callee and not a parameter to the call.
+                  // 
+                  // FIXME: Determine if there's a way to say that `F' is the
+                  // callee or parameter.
+                  DoesNotThrow = false;
+                  break;
+                }
                 if (F->doesNotThrow()) {
+                  SawFunc = true;
                   DoesNotThrow = true;
-                  break;
                 }
               }
             }