DebugInfo: Ensure that all debug location scope chains from instructions within a...

Originally committed in r211723, reverted in r211724 due to failure
cases found and fixed (ArgumentPromotion: r211872, Inlining: r212065),
and I now believe the invariant actually holds for some reasonable
amount of code (but I'll keep an eye on the buildbots and see what
happens... ).

Original commit message:

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@212085 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index f78ca2c03b4ec247a29ce4e2ee141318da349244..5aa2659fb6c5339ff1025e3390ba1af8afa7d190 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -786,8 +786,7 @@ void DwarfDebug::finishVariableDefinitions() {
   for (const auto &Var : ConcreteVariables) {
     DIE *VariableDie = Var->getDIE();
     // FIXME: There shouldn't be any variables without DIEs.
-    if (!VariableDie)
-      continue;
+    assert(VariableDie);
     // FIXME: Consider the time-space tradeoff of just storing the unit pointer
     // in the ConcreteVariables list, rather than looking it up again here.
     // DIE::getUnit isn't simple - it walks parent pointers, etc.

diff --git a/lib/CodeGen/LexicalScopes.cpp b/lib/CodeGen/LexicalScopes.cpp
index d12c234bf3b20343eea3d8b7dc740dc476eb7485..f67c717d4e412915b0a9ef0ba443c33a285db226 100644 (file)
--- a/lib/CodeGen/LexicalScopes.cpp
+++ b/lib/CodeGen/LexicalScopes.cpp
@@ -137,6 +137,8 @@ LexicalScope *LexicalScopes::findLexicalScope(DebugLoc DL) {
 /// 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::getOrCreateRegularScope(MDNode *Scope) {
                               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;
 }

diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index 9f35efa1ad993a0dc76b1dab21ff8829e66e017a..e32cc9dffbc2b9fe469da3d99fb1264b7fce2b3a 100644 (file)
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -538,6 +538,32 @@ 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;
 }
 

diff --git a/test/DebugInfo/PR20038.ll b/test/DebugInfo/PR20038.ll
index a9fb3ff3b604f908e2b33afb7222306f0f974fdf..61145e5c8441d5a9deecd32ec7c265505febd6b6 100644 (file)
--- a/test/DebugInfo/PR20038.ll
+++ b/test/DebugInfo/PR20038.ll
@@ -18,26 +18,38 @@
 ; CHECK-NOT: DW_TAG
 ; CHECK:     DW_AT_name {{.*}} "~C"
 
-; CHECK: DW_TAG_subprogram
+; CHECK: [[D1_ABS:.*]]: DW_TAG_subprogram
 ; CHECK-NOT: DW_TAG
-; CHECK:   DW_AT_name {{.*}} "fun4"
-
-; FIXME: The dtor is inlined into fun4 and should have an inlined_subroutine
-; entry. (it may be necessary to put some non-trivial instruction, such as an
-; assignment to a global, in the dtor just to ensure its emission/inlining)
-
-; CHECK-NOT: DW_TAG_inlined_subroutine
+; CHECK:   DW_AT_MIPS_linkage_name {{.*}} "_ZN1CD1Ev"
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK: [[D1_THIS_ABS:.*]]:   DW_TAG_formal_parameter
+; CHECK-NOT: DW_TAG
+; CHECK:     DW_AT_name {{.*}} "this"
 
 ; CHECK: DW_TAG_subprogram
 ; CHECK-NOT: DW_TAG
-; CHECK: DW_AT_MIPS_linkage_name {{.*}} "_ZN1CD1Ev"
+; CHECK:   DW_AT_name {{.*}} "fun4"
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:   DW_TAG_lexical_block
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK-NOT: DW_TAG
+; CHECK:       DW_AT_abstract_origin {{.*}} {[[D1_ABS]]}
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:       DW_TAG_formal_parameter
+; CHECK-NOT: DW_TAG
+; CHECK:         DW_AT_abstract_origin {{.*}} {[[D1_THIS_ABS]]}
 
-; FIXME: But I think where the real issue is for PR20038 is that the D1 ctor, ;
-; calling and inlining D2, doesn't end up with an inlined_subroutine. Though this
-; might be more the result of a lack of any actual work in D2 (again, could use
-; an assignment to global, etc)
+; FIXME: D2 is actually inlined into D1 but doesn't show up here, possibly due
+; to there being no work in D2 (calling another member function from the dtor
+; causes D2 to show up, calling a free function doesn't).
 
-; CHECK-NOT: DW_TAG_inlined_subroutine
+; CHECK-NOT: DW_TAG
+; CHECK:       NULL
+; CHECK-NOT: DW_TAG
+; CHECK:     NULL
+; CHECK-NOT: DW_TAG
+; CHECK:   NULL
 
 %struct.C = type { i8 }
 
@@ -47,48 +59,48 @@
 define void @_Z4fun4v() #0 {
 entry:
   %this.addr.i.i = alloca %struct.C*, align 8, !dbg !21
-  %this.addr.i = alloca %struct.C*, align 8
+  %this.addr.i = alloca %struct.C*, align 8, !dbg !22
   %agg.tmp.ensured = alloca %struct.C, align 1
   %cleanup.cond = alloca i1
-  %0 = load i8* @b, align 1, !dbg !22
-  %tobool = trunc i8 %0 to i1, !dbg !22
+  %0 = load i8* @b, align 1, !dbg !24
+  %tobool = trunc i8 %0 to i1, !dbg !24
   store i1 false, i1* %cleanup.cond
-  br i1 %tobool, label %land.rhs, label %land.end, !dbg !22
+  br i1 %tobool, label %land.rhs, label %land.end, !dbg !24
 
 land.rhs:                                         ; preds = %entry
-  store i1 true, i1* %cleanup.cond, !dbg !23
+  store i1 true, i1* %cleanup.cond, !dbg !25
   br label %land.end
 
 land.end:                                         ; preds = %land.rhs, %entry
   %1 = phi i1 [ false, %entry ], [ true, %land.rhs ]
-  %cleanup.is_active = load i1* %cleanup.cond
-  br i1 %cleanup.is_active, label %cleanup.action, label %cleanup.done
+  %cleanup.is_active = load i1* %cleanup.cond, !dbg !27
+  br i1 %cleanup.is_active, label %cleanup.action, label %cleanup.done, !dbg !27
 
 cleanup.action:                                   ; preds = %land.end
-  store %struct.C* %agg.tmp.ensured, %struct.C** %this.addr.i, align 8
-  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr.i}, metadata !25), !dbg !27
-  %this1.i = load %struct.C** %this.addr.i
+  store %struct.C* %agg.tmp.ensured, %struct.C** %this.addr.i, align 8, !dbg !22
+  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr.i}, metadata !29), !dbg !31
+  %this1.i = load %struct.C** %this.addr.i, !dbg !22
   store %struct.C* %this1.i, %struct.C** %this.addr.i.i, align 8, !dbg !21
-  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr.i.i}, metadata !28), !dbg !29
+  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr.i.i}, metadata !32), !dbg !33
   %this1.i.i = load %struct.C** %this.addr.i.i, !dbg !21
-  br label %cleanup.done
+  br label %cleanup.done, !dbg !22
 
 cleanup.done:                                     ; preds = %cleanup.action, %land.end
-  ret void, !dbg !22
+  ret void, !dbg !34
 }
 
 ; Function Attrs: alwaysinline nounwind
 define void @_ZN1CD1Ev(%struct.C* %this) unnamed_addr #1 align 2 {
 entry:
-  %this.addr.i = alloca %struct.C*, align 8, !dbg !21
+  %this.addr.i = alloca %struct.C*, align 8, !dbg !37
   %this.addr = alloca %struct.C*, align 8
   store %struct.C* %this, %struct.C** %this.addr, align 8
-  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr}, metadata !25), !dbg !27
+  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr}, metadata !29), !dbg !38
   %this1 = load %struct.C** %this.addr
-  store %struct.C* %this1, %struct.C** %this.addr.i, align 8, !dbg !21
-  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr.i}, metadata !28), !dbg !29
-  %this1.i = load %struct.C** %this.addr.i, !dbg !21
-  ret void, !dbg !21
+  store %struct.C* %this1, %struct.C** %this.addr.i, align 8, !dbg !37
+  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr.i}, metadata !32), !dbg !39
+  %this1.i = load %struct.C** %this.addr.i, !dbg !37
+  ret void, !dbg !37
 }
 
 ; Function Attrs: alwaysinline nounwind
@@ -96,9 +108,9 @@ define void @_ZN1CD2Ev(%struct.C* %this) unnamed_addr #1 align 2 {
 entry:
   %this.addr = alloca %struct.C*, align 8
   store %struct.C* %this, %struct.C** %this.addr, align 8
-  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr}, metadata !28), !dbg !30
+  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr}, metadata !32), !dbg !40
   %this1 = load %struct.C** %this.addr
-  ret void, !dbg !31
+  ret void, !dbg !41
 }
 
 ; Function Attrs: nounwind readnone
@@ -133,14 +145,24 @@ attributes #2 = { nounwind readnone }
 !18 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
 !19 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
 !20 = metadata !{metadata !"clang version 3.5.0 "}
-!21 = metadata !{i32 6, i32 0, metadata !17, null}
-!22 = metadata !{i32 5, i32 0, metadata !12, null}
-!23 = metadata !{i32 5, i32 0, metadata !24, null}
-!24 = metadata !{i32 786443, metadata !5, metadata !12, i32 5, i32 0, i32 1, i32 1} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/PR20038.cpp]
-!25 = metadata !{i32 786689, metadata !17, metadata !"this", null, i32 16777216, metadata !26, i32 1088, i32 0} ; [ DW_TAG_arg_variable ] [this] [line 0]
-!26 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !"_ZTS1C"} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from _ZTS1C]
-!27 = metadata !{i32 0, i32 0, metadata !17, null}
-!28 = metadata !{i32 786689, metadata !16, metadata !"this", null, i32 16777216, metadata !26, i32 1088, i32 0} ; [ DW_TAG_arg_variable ] [this] [line 0]
-!29 = metadata !{i32 0, i32 0, metadata !16, metadata !21}
-!30 = metadata !{i32 0, i32 0, metadata !16, null}
-!31 = metadata !{i32 6, i32 0, metadata !16, null}
+!21 = metadata !{i32 6, i32 0, metadata !17, metadata !22}
+!22 = metadata !{i32 5, i32 0, metadata !23, null}
+!23 = metadata !{i32 786443, metadata !5, metadata !12, i32 5, i32 0, i32 3, i32 3} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/PR20038.cpp]
+!24 = metadata !{i32 5, i32 0, metadata !12, null}
+!25 = metadata !{i32 5, i32 0, metadata !26, null}
+!26 = metadata !{i32 786443, metadata !5, metadata !12, i32 5, i32 0, i32 1, i32 1} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/PR20038.cpp]
+!27 = metadata !{i32 5, i32 0, metadata !28, null}
+!28 = metadata !{i32 786443, metadata !5, metadata !12, i32 5, i32 0, i32 2, i32 2} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/PR20038.cpp]
+!29 = metadata !{i32 786689, metadata !17, metadata !"this", null, i32 16777216, metadata !30, i32 1088, i32 0} ; [ DW_TAG_arg_variable ] [this] [line 0]
+!30 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, metadata !"_ZTS1C"} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from _ZTS1C]
+!31 = metadata !{i32 0, i32 0, metadata !17, metadata !22}
+!32 = metadata !{i32 786689, metadata !16, metadata !"this", null, i32 16777216, metadata !30, i32 1088, i32 0} ; [ DW_TAG_arg_variable ] [this] [line 0]
+!33 = metadata !{i32 0, i32 0, metadata !16, metadata !21}
+!34 = metadata !{i32 5, i32 0, metadata !35, null}
+!35 = metadata !{i32 786443, metadata !5, metadata !36, i32 5, i32 0, i32 5, i32 5} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/PR20038.cpp]
+!36 = metadata !{i32 786443, metadata !5, metadata !12, i32 5, i32 0, i32 4, i32 4} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/PR20038.cpp]
+!37 = metadata !{i32 6, i32 0, metadata !17, null}
+!38 = metadata !{i32 0, i32 0, metadata !17, null}
+!39 = metadata !{i32 0, i32 0, metadata !16, metadata !37}
+!40 = metadata !{i32 0, i32 0, metadata !16, null}
+!41 = metadata !{i32 6, i32 0, metadata !16, null}