[PATCH] D14697: [Verifier] Fix !dbg validation if Scope is the Subprogram

[Keno Fischer via llvm-commits]

loladiro created this revision.
loladiro added reviewers: pcc, dblaikie, dexonsmith.
loladiro added a subscriber: llvm-commits.

We are inserting both Scope and SP into the Seen map and check whether
it was already there in which case we skip the validation (the idea
being that we already checked this Subprogram before). However,
if (Scope == SP) as MDNodes, then inserting the Scope, will trigger
the Seen check causing us to incorrectly not validate this !dbg
attachment. Fix this by not performing the SP Seen check if Scope == SP

http://reviews.llvm.org/D14697

Files:
  lib/IR/Verifier.cpp
  test/CodeGen/X86/2010-05-28-Crash.ll
  test/Verifier/func-dbg.ll

Index: test/Verifier/func-dbg.ll
===================================================================
--- /dev/null
+++ test/Verifier/func-dbg.ll
@@ -0,0 +1,25 @@
+; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
+
+define i32 @foo() !dbg !4 {
+entry:
+  ret i32 0, !dbg !6
+}
+
+define i32 @bar() !dbg !5 {
+entry:
+; CHECK: !dbg attachment points at wrong subprogram for function
+  ret i32 0, !dbg !6
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: 0, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
+!1 = !DIFile(filename: "dwarf-test.c", directory: "test")
+!2 = !{}
+!3 = !{!4, !5}
+!4 = distinct !DISubprogram(name: "foo", scope: !0, isDefinition: true)
+!5 = distinct !DISubprogram(name: "bar", scope: !0, isDefinition: true)
+!6 = !DILocation(line: 7, scope: !4)
+!7 = !{i32 2, !"Dwarf Version", i32 3}
+!8 = !{i32 1, !"Debug Info Version", i32 3}
Index: test/CodeGen/X86/2010-05-28-Crash.ll
===================================================================
--- test/CodeGen/X86/2010-05-28-Crash.ll
+++ test/CodeGen/X86/2010-05-28-Crash.ll
@@ -16,7 +16,7 @@
 define i32 @bar(i32 %x) nounwind optsize ssp !dbg !8 {
 entry:
   tail call void @llvm.dbg.value(metadata i32 %x, i64 0, metadata !7, metadata !DIExpression()), !dbg !DILocation(scope: !8)
-  tail call void @llvm.dbg.value(metadata i32 1, i64 0, metadata !0, metadata !DIExpression()) nounwind, !dbg !DILocation(scope: !1)
+  tail call void @llvm.dbg.value(metadata i32 1, i64 0, metadata !0, metadata !DIExpression()) nounwind, !dbg !DILocation(scope: !1, inlinedAt: !DILocation(scope: !8))
   %0 = tail call i32 (...) @zoo(i32 1) nounwind, !dbg !12 ; <i32> [#uses=1]
   %1 = add nsw i32 %0, %x, !dbg !13               ; <i32> [#uses=1]
   ret i32 %1, !dbg !13
Index: lib/IR/Verifier.cpp
===================================================================
--- lib/IR/Verifier.cpp
+++ lib/IR/Verifier.cpp
@@ -1806,7 +1806,11 @@
         continue;
 
       DISubprogram *SP = Scope ? Scope->getSubprogram() : nullptr;
-      if (SP && !Seen.insert(SP).second)
+
+      // Scope and SP could be the same MDNode and we don't want to skip
+      // validation in that case
+      if (SP && ((Scope != SP)
+             && !Seen.insert(SP).second))
         continue;
 
       // FIXME: Once N is canonical, check "SP == &N".


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