[llvm] r219702 - DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself.

[David Blaikie]

Author: dblaikie
Date: Tue Oct 14 13:22:52 2014
New Revision: 219702

URL: http://llvm.org/viewvc/llvm-project?rev=219702&view=rev
Log:
DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself.

Let me tell you a tale...

Originally committed in r211723 after discovering a nasty case of weird
scoping due to inlining, this was reverted in r211724 after it fired in
ASan/compiler-rt.

(minor diversion where I accidentally committed/reverted again in
r211871/r211873)

After further testing and fixing bugs in ArgumentPromotion (r211872) and
Inlining (r212065) it was recommitted in r212085. Reverted in r212089
after the sanitizer buildbots still showed problems.

Fixed another bug in ArgumentPromotion (r212128) found by this
assertion.

Recommitted in r212205, reverted in r212226 after it crashed some more
on sanitizer buildbots.

Fix clang some more in r212761.

Recommitted in r212776, reverted in r212793. ASan failures.
Recommitted in r213391, reverted in r213432, trying to reproduce flakey
ASan build failure.

Fixed bugs in r213805 (ArgPromo + DebugInfo), r213952
(LiveDebugVariables strips dbg_value intrinsics in functions not
described by debug info).

Recommitted in r214761, reverted in r214999, flakey failure on Windows
buildbot.

Fixed DeadArgElimination + DebugInfo bug in r219210.

Recommitted in r219215, reverted in r219512, failure on ObjC++ atomic
properties in the test-suite on Darwin.

Fixed ObjC++ atomic properties issue in Clang in r219690.

[This commit is provided 'as is' with no hope that this is the last time
I commit this change either expressed or implied]

Modified:
    llvm/trunk/lib/CodeGen/LexicalScopes.cpp
    llvm/trunk/lib/IR/DebugInfo.cpp

Modified: llvm/trunk/lib/CodeGen/LexicalScopes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LexicalScopes.cpp?rev=219702&r1=219701&r2=219702&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LexicalScopes.cpp (original)
+++ llvm/trunk/lib/CodeGen/LexicalScopes.cpp Tue Oct 14 13:22:52 2014
@@ -137,6 +137,8 @@ LexicalScope *LexicalScopes::findLexical
 /// getOrCreateLexicalScope - Find lexical scope for the given DebugLoc. If
 /// not available then create new lexical scope.
 LexicalScope *LexicalScopes::getOrCreateLexicalScope(DebugLoc DL) {
+  if (DL.isUnknown())
+    return nullptr;
   MDNode *Scope = nullptr;
   MDNode *InlinedAt = nullptr;
   DL.getScopeAndInlinedAt(Scope, InlinedAt, MF->getFunction()->getContext());
@@ -172,9 +174,12 @@ LexicalScope *LexicalScopes::getOrCreate
                               std::make_tuple(Parent, DIDescriptor(Scope),
                                               nullptr, false)).first;
 
-  if (!Parent && DIDescriptor(Scope).isSubprogram() &&
-      DISubprogram(Scope).describes(MF->getFunction()))
+  if (!Parent) {
+    assert(DIDescriptor(Scope).isSubprogram());
+    assert(DISubprogram(Scope).describes(MF->getFunction()));
+    assert(!CurrentFnLexicalScope);
     CurrentFnLexicalScope = &I->second;
+  }
 
   return &I->second;
 }

Modified: llvm/trunk/lib/IR/DebugInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DebugInfo.cpp?rev=219702&r1=219701&r2=219702&view=diff
==============================================================================
--- llvm/trunk/lib/IR/DebugInfo.cpp (original)
+++ llvm/trunk/lib/IR/DebugInfo.cpp Tue Oct 14 13:22:52 2014
@@ -568,6 +568,34 @@ bool DISubprogram::Verify() const {
   if (isLValueReference() && isRValueReference())
     return false;
 
+  // If a DISubprogram has an llvm::Function*, then scope chains from all
+  // instructions within the function should lead to this DISubprogram.
+  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() == 9 && getNumHeaderFields() == 12;
 }