Make it illegal for two Functions to point to the same DISubprogram

As recently discussed on llvm-dev [1], this patch makes it illegal for
two Functions to point to the same DISubprogram and updates
FunctionCloner to also clone the debug info of a function to conform
to the new requirement. To simplify the implementation it also factors
out the creation of inlineAt locations from the Inliner into a
general-purpose utility in DILocation.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-May/112661.html
<rdar://problem/31926379>

Differential Revision: https://reviews.llvm.org/D32975

llvm-svn: 302469

1 files changed, 5 insertions, 38 deletions

diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 6d56e08..bafccaa 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1302,41 +1302,6 @@ static bool hasLifetimeMarkers(AllocaInst *AI) {
   return false;
 }
 
-/// Rebuild the entire inlined-at chain for this instruction so that the top of
-/// the chain now is inlined-at the new call site.
-static DebugLoc
-updateInlinedAtInfo(const DebugLoc &DL, DILocation *InlinedAtNode,
-                    LLVMContext &Ctx,
-                    DenseMap<const DILocation *, DILocation *> &IANodes) {
-  SmallVector<DILocation *, 3> InlinedAtLocations;
-  DILocation *Last = InlinedAtNode;
-  DILocation *CurInlinedAt = DL;
-
-  // Gather all the inlined-at nodes
-  while (DILocation *IA = CurInlinedAt->getInlinedAt()) {
-    // Skip any we've already built nodes for
-    if (DILocation *Found = IANodes[IA]) {
-      Last = Found;
-      break;
-    }
-
-    InlinedAtLocations.push_back(IA);
-    CurInlinedAt = IA;
-  }
-
-  // Starting from the top, rebuild the nodes to point to the new inlined-at
-  // location (then rebuilding the rest of the chain behind it) and update the
-  // map of already-constructed inlined-at nodes.
-  for (const DILocation *MD : reverse(InlinedAtLocations)) {
-    Last = IANodes[MD] = DILocation::getDistinct(
-        Ctx, MD->getLine(), MD->getColumn(), MD->getScope(), Last);
-  }
-
-  // And finally create the normal location for this instruction, referring to
-  // the new inlined-at chain.
-  return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(), Last);
-}
-
 /// Return the result of AI->isStaticAlloca() if AI were moved to the entry
 /// block. Allocas used in inalloca calls and allocas of dynamic array size
 /// cannot be static.
@@ -1364,14 +1329,16 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
   // Cache the inlined-at nodes as they're built so they are reused, without
   // this every instruction's inlined-at chain would become distinct from each
   // other.
-  DenseMap<const DILocation *, DILocation *> IANodes;
+  DenseMap<const MDNode *, MDNode *> IANodes;
 
   for (; FI != Fn->end(); ++FI) {
     for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
          BI != BE; ++BI) {
       if (DebugLoc DL = BI->getDebugLoc()) {
-        BI->setDebugLoc(
-            updateInlinedAtInfo(DL, InlinedAtNode, BI->getContext(), IANodes));
+        auto IA = DebugLoc::appendInlinedAt(DL, InlinedAtNode, BI->getContext(),
+                                            IANodes);
+        auto IDL = DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(), IA);
+        BI->setDebugLoc(IDL);
         continue;
       }