From f6c836251f3b409c89bffbe0808a1962116bef34 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Steinbrink?= <steinbrink@saltation.de>
Date: Wed, 4 Oct 2017 16:00:22 +0200
Subject: [PATCH] Ignore all duplicate frame index expression

Some passes might duplicate calls to llvm.dbg.declare creating
duplicate frame index expression which currently trigger an assertion
which is meant to catch erroneous, overlapping fragment declarations.
But identical frame index expressions are just redundant and don't
actually conflict with each other, so we can be more lenient and just
ignore the duplicates.

Reviewers: aprantl, rnk

Subscribers: llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D38540
---
 lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 25 +++++++++++++++++++++++++
 lib/CodeGen/AsmPrinter/DwarfDebug.h   | 18 +-----------------
 2 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 91a3d0989cc5..88ba0e63cd12 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -205,9 +205,34 @@ ArrayRef<DbgVariable::FrameIndexExpr> DbgVariable::getFrameIndexExprs() const {
               return A.Expr->getFragmentInfo()->OffsetInBits <
                      B.Expr->getFragmentInfo()->OffsetInBits;
             });
+
   return FrameIndexExprs;
 }
 
+void DbgVariable::addMMIEntry(const DbgVariable &V) {
+  assert(DebugLocListIndex == ~0U && !MInsn && "not an MMI entry");
+  assert(V.DebugLocListIndex == ~0U && !V.MInsn && "not an MMI entry");
+  assert(V.Var == Var && "conflicting variable");
+  assert(V.IA == IA && "conflicting inlined-at location");
+
+  assert(!FrameIndexExprs.empty() && "Expected an MMI entry");
+  assert(!V.FrameIndexExprs.empty() && "Expected an MMI entry");
+
+  for (const auto &FIE : V.FrameIndexExprs)
+    // Ignore duplicate entries.
+    if (llvm::none_of(FrameIndexExprs, [&](const FrameIndexExpr &Other) {
+          return FIE.FI == Other.FI && FIE.Expr == Other.Expr;
+        }))
+      FrameIndexExprs.push_back(FIE);
+
+  assert((FrameIndexExprs.size() == 1 ||
+          llvm::all_of(FrameIndexExprs,
+                       [](FrameIndexExpr &FIE) {
+                         return FIE.Expr && FIE.Expr->isFragment();
+                       })) &&
+         "conflicting locations for variable");
+}
+
 static const DwarfAccelTable::Atom TypeAtoms[] = {
     DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4),
     DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2),
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 253e3f06200e..1e6a25ea9935 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -124,23 +124,7 @@ class DbgVariable {
   /// Get the FI entries, sorted by fragment offset.
   ArrayRef<FrameIndexExpr> getFrameIndexExprs() const;
   bool hasFrameIndexExprs() const { return !FrameIndexExprs.empty(); }
-
-  void addMMIEntry(const DbgVariable &V) {
-    assert(DebugLocListIndex == ~0U && !MInsn && "not an MMI entry");
-    assert(V.DebugLocListIndex == ~0U && !V.MInsn && "not an MMI entry");
-    assert(V.Var == Var && "conflicting variable");
-    assert(V.IA == IA && "conflicting inlined-at location");
-
-    assert(!FrameIndexExprs.empty() && "Expected an MMI entry");
-    assert(!V.FrameIndexExprs.empty() && "Expected an MMI entry");
-
-    FrameIndexExprs.append(V.FrameIndexExprs.begin(), V.FrameIndexExprs.end());
-    assert(all_of(FrameIndexExprs,
-                  [](FrameIndexExpr &FIE) {
-                    return FIE.Expr && FIE.Expr->isFragment();
-                  }) &&
-           "conflicting locations for variable");
-  }
+  void addMMIEntry(const DbgVariable &V);
 
   // Translate tag to proper Dwarf tag.
   dwarf::Tag getTag() const {