[llvm] 5c83bed - More principled implementation of DISubprogram::describes()

[Adrian Prantl via llvm-commits]

Author: Adrian Prantl
Date: 2020-03-02T10:03:14-08:00
New Revision: 5c83bedecab94f4dbbb0449cced31aec1b8aaac5

URL: https://github.com/llvm/llvm-project/commit/5c83bedecab94f4dbbb0449cced31aec1b8aaac5
DIFF: https://github.com/llvm/llvm-project/commit/5c83bedecab94f4dbbb0449cced31aec1b8aaac5.diff

LOG: More principled implementation of DISubprogram::describes()

Previously we would also accept DISubprograms that matched in name
only, but this doesn't appear to be necessary any more.

I did a Full and Thin LTO build of Clang and it completed without a warning.

Differential Revision: https://reviews.llvm.org/D75213

Added: 
    llvm/test/Verifier/disubprogram-name-match-only.ll

Modified: 
    llvm/lib/IR/DebugInfoMetadata.cpp
    llvm/lib/IR/Verifier.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index b630a2893b4d..bd8829e92656 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -660,12 +660,7 @@ DISubprogram *DISubprogram::getImpl(
 
 bool DISubprogram::describes(const Function *F) const {
   assert(F && "Invalid function");
-  if (F->getSubprogram() == this)
-    return true;
-  StringRef Name = getLinkageName();
-  if (Name.empty())
-    Name = getName();
-  return F->getName() == Name;
+  return F->getSubprogram() == this;
 }
 
 DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,

diff  --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index cf0eac908652..eaabd553e95b 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2364,8 +2364,7 @@ void Verifier::visitFunction(const Function &F) {
   if (!HasDebugInfo)
     return;
 
-  // Check that all !dbg attachments lead to back to N (or, at least, another
-  // subprogram that describes the same function).
+  // Check that all !dbg attachments lead to back to N.
   //
   // FIXME: Check this incrementally while visiting !dbg attachments.
   // FIXME: Only check when N is the canonical subprogram for F.
@@ -2394,11 +2393,9 @@ void Verifier::visitFunction(const Function &F) {
     if (SP && ((Scope != SP) && !Seen.insert(SP).second))
       return;
 
-    // FIXME: Once N is canonical, check "SP == &N".
     AssertDI(SP->describes(&F),
              "!dbg attachment points at wrong subprogram for function", N, &F,
              &I, DL, Scope, SP);
-    visitMDNode(*SP);
   };
   for (auto &BB : F)
     for (auto &I : BB) {

diff  --git a/llvm/test/Verifier/disubprogram-name-match-only.ll b/llvm/test/Verifier/disubprogram-name-match-only.ll
new file mode 100644
index 000000000000..ae23ae201d55
--- /dev/null
+++ b/llvm/test/Verifier/disubprogram-name-match-only.ll
@@ -0,0 +1,26 @@
+; RUN: llvm-as -disable-output <%s 2>&1| FileCheck %s
+
+define void @f() !dbg !14 {
+  ret void, !dbg !5
+}
+
+!llvm.module.flags = !{!15}
+!llvm.dbg.cu = !{!4}
+
+!0 = !{null}
+!1 = distinct !DICompositeType(tag: DW_TAG_structure_type)
+!2 = !DIFile(filename: "f.c", directory: "/")
+!3 = !DISubroutineType(types: !0)
+!4 = distinct !DICompileUnit(language: DW_LANG_C, file: !2)
+; CHECK: !dbg attachment points at wrong subprogram for function
+; CHECK: warning: ignoring invalid debug info
+!5 = !DILocation(line: 1, scope: !9)
+!9 = distinct !DISubprogram(name: "f", scope: !1,
+                            file: !2, line: 1, type: !3, isLocal: true,
+                            isDefinition: true, scopeLine: 2,
+                            unit: !4)
+!14 = distinct !DISubprogram(name: "f", scope: !1,
+                            file: !2, line: 1, type: !3, isLocal: true,
+                            isDefinition: true, scopeLine: 2,
+                            unit: !4)
+!15 = !{i32 1, !"Debug Info Version", i32 3}