Patch by David Meyer to avoid a O(N^2) behaviour when relaxing fragments.

Since we now don't update addresses so early, we might relax a bit more than
we need to. This is simillar to the issue in PR8467.

llvm-svn: 121856

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 5bc477d7bcc..f05f6acd632 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -738,6 +738,7 @@ bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
   bool WasRelaxed = false;
   for (iterator it = begin(), ie = end(); it != ie; ++it) {
     MCSectionData &SD = *it;
+    MCFragment *FirstInvalidFragment = NULL;
 
     for (MCSectionData::iterator it2 = SD.begin(),
            ie2 = SD.end(); it2 != ie2; ++it2) {
@@ -762,10 +763,12 @@ bool MCAssembler::LayoutOnce(const MCObjectWriter &Writer,
         break;
       }
       // Update the layout, and remember that we relaxed.
-      if (relaxedFrag)
-	Layout.Invalidate(it2);
+      if (relaxedFrag && !FirstInvalidFragment)
+        FirstInvalidFragment = it2;
       WasRelaxed |= relaxedFrag;
     }
+    if (FirstInvalidFragment)
+      Layout.Invalidate(FirstInvalidFragment);
   }
 
   return WasRelaxed;