From c39f36df61fd69fc856c92ce8e6700b6b5357c20 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Wed, 25 Jun 2014 18:03:10 +0000
Subject: PR20038: DebugInfo: Inlined call sites where the caller has debug
 info but the call itself has no debug location.

This situation does bad things when inlined, so I've fixed Clang not to
produce inlinable call sites without locations when the caller has debug
info (in the one case where I could find that this occurred). This
updates the PR20038 test case to be what clang now produces, and readds
the assertion that had to be removed due to this bug.

I've also beefed up the debug info verifier to help diagnose these
issues in the future, and I hope to add checks to the inliner to just
assert-fail if it encounters this situation. If, in the future, we
decide we have to cope with this situation, the right thing to do is
probably to just remove all the DebugLocs from the inlined instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211723 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/IR/DebugInfo.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

(limited to 'lib/IR')

diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index db9e56defa..2023be313b 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -532,6 +532,32 @@ bool DISubprogram::Verify() const {
   if (isLValueReference() && isRValueReference())
     return false;
 
+  if (auto *F = getFunction()) {
+    LLVMContext &Ctxt = F->getContext();
+    for (auto &BB : *F) {
+      for (auto &I : BB) {
+        DebugLoc DL = I.getDebugLoc();
+        if (DL.isUnknown())
+          continue;
+
+        MDNode *Scope = nullptr;
+        MDNode *IA = nullptr;
+        // walk the inlined-at scopes
+        while (DL.getScopeAndInlinedAt(Scope, IA, F->getContext()), IA)
+          DL = DebugLoc::getFromDILocation(IA);
+        DL.getScopeAndInlinedAt(Scope, IA, Ctxt);
+        assert(!IA);
+        while (!DIDescriptor(Scope).isSubprogram()) {
+          DILexicalBlockFile D(Scope);
+          Scope = D.isLexicalBlockFile()
+                      ? D.getScope()
+                      : DebugLoc::getFromDILexicalBlock(Scope).getScope(Ctxt);
+        }
+        if (!DISubprogram(Scope).describes(F))
+          return false;
+      }
+    }
+  }
   return DbgNode->getNumOperands() == 20;
 }
 
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