Revert r302469 "Make it illegal for two Functions to point to the same DISubprogram"

This caused PR32977.

Original commit message:

> 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: 302533

1 files changed, 38 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index bafccaa..6d56e08 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1302,6 +1302,41 @@ 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.
@@ -1329,16 +1364,14 @@ 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 MDNode *, MDNode *> IANodes;
+  DenseMap<const DILocation *, DILocation *> IANodes;
 
   for (; FI != Fn->end(); ++FI) {
     for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
          BI != BE; ++BI) {
       if (DebugLoc DL = BI->getDebugLoc()) {
-        auto IA = DebugLoc::appendInlinedAt(DL, InlinedAtNode, BI->getContext(),
-                                            IANodes);
-        auto IDL = DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(), IA);
-        BI->setDebugLoc(IDL);
+        BI->setDebugLoc(
+            updateInlinedAtInfo(DL, InlinedAtNode, BI->getContext(), IANodes));
         continue;
       }