Temporarily revert r104655 as it's breaking the bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104664 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 37 insertions, 5 deletions

diff --git a/lib/CodeGen/StackSlotColoring.cpp b/lib/CodeGen/StackSlotColoring.cpp
index 354878aa42..8043556349 100644
--- a/lib/CodeGen/StackSlotColoring.cpp
+++ b/lib/CodeGen/StackSlotColoring.cpp
@@ -118,6 +118,7 @@ namespace {
 
   private:
     void InitializeSlots();
+    bool CheckForSetJmpCall(const MachineFunction &MF) const;
     void ScanForSpillSlotRefs(MachineFunction &MF);
     bool OverlapWithAssignments(LiveInterval *li, int Color) const;
     int ColorSlot(LiveInterval *li);
@@ -161,6 +162,34 @@ namespace {
   };
 }
 
+/// CheckForSetJmpCall - Return true if there's a call to setjmp/sigsetjmp in
+/// this function.
+bool StackSlotColoring::CheckForSetJmpCall(const MachineFunction &MF) const {
+  const Function *F = MF.getFunction();
+  const Module *M = F->getParent();
+  const Function *SetJmp = M->getFunction("setjmp");
+  const Function *SigSetJmp = M->getFunction("sigsetjmp");
+
+  if (!SetJmp && !SigSetJmp)
+    return false;
+
+  if (SetJmp && !SetJmp->use_empty())
+    for (Value::const_use_iterator
+           I = SetJmp->use_begin(), E = SetJmp->use_end(); I != E; ++I)
+      if (const CallInst *CI = dyn_cast<CallInst>(I))
+        if (CI->getParent()->getParent() == F)
+          return true;
+
+  if (SigSetJmp && !SigSetJmp->use_empty())
+    for (Value::const_use_iterator
+           I = SigSetJmp->use_begin(), E = SigSetJmp->use_end(); I != E; ++I)
+      if (const CallInst *CI = dyn_cast<CallInst>(I))
+        if (CI->getParent()->getParent() == F)
+          return true;
+
+  return false;
+}
+
 /// ScanForSpillSlotRefs - Scan all the machine instructions for spill slot
 /// references and update spill slot weights.
 void StackSlotColoring::ScanForSpillSlotRefs(MachineFunction &MF) {
@@ -724,11 +753,14 @@ bool StackSlotColoring::runOnMachineFunction(MachineFunction &MF) {
       return false;
   }
 
-  // If there is a call to a function with the attribute "returns_twice" (like
-  // setjmp or sigsetjmp), don't perform stack slot coloring. The stack could be
-  // modified before the the second return, resulting in the wrong value being
-  // used afterwards. (See <rdar://problem/8007500>.)
-  if (MF.hasReturnsTwiceCall())
+  // If there are calls to setjmp or sigsetjmp, don't perform stack slot
+  // coloring. The stack could be modified before the longjmp is executed,
+  // resulting in the wrong value being used afterwards. (See
+  // <rdar://problem/8007500>.)
+  //
+  // FIXME: This goes beyond the setjmp/sigsetjmp functions. Ideally, we should
+  // check for the GCC "returns twice" attribute.
+  if (CheckForSetJmpCall(MF))
     return false;
 
   // Gather spill slot references