From f3a2cfc10394143bbe30a6af00be8b68c1c0d607 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Thu, 10 Feb 2022 14:40:25 -0800
Subject: [PATCH] DebugInfo: Don't simplify any template referencing a lambda
Lambda names aren't entirely canonical (as demonstrated by the
cross-project-test added here) at the moment (we should fix that for a
bunch of reasons) - even if the template referencing them is
non-simplified, other names referencing /that/ template can't be
simplified either because type units might cause a different template to
be picked up that would conflict with the expected name.
(other than for roundtripping precision, it'd be OK to simplify types
that reference types that reference lambdas - but best be consistent
between the roundtrip/verify mode and the actual simplified template
names mode)
---
clang/lib/CodeGen/CGDebugInfo.cpp | 58 +++++++++++++++----
.../debug-info-simple-template-names.cpp | 8 ++-
.../simplified_template_names.cpp | 1 +
...template_names_noncanonical_type_units.cpp | 40 +++++++++++++
4 files changed, 94 insertions(+), 13 deletions(-)
create mode 100644 cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names_noncanonical_type_units.cpp
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 1a9080604a79..cca5576aac07 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -4975,6 +4975,52 @@ llvm::DIGlobalVariableExpression *CGDebugInfo::CollectAnonRecordDecls(
return GVE;
}
+static bool ReferencesAnonymousEntity(ArrayRef<TemplateArgument> Args);
+static bool ReferencesAnonymousEntity(RecordType *RT) {
+ // Unnamed classes/lambdas can't be reconstituted due to a lack of column
+ // info we produce in the DWARF, so we can't get Clang's full name back.
+ // But so long as it's not one of those, it doesn't matter if some sub-type
+ // of the record (a template parameter) can't be reconstituted - because the
+ // un-reconstitutable type itself will carry its own name.
+ const auto *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
+ if (!RD)
+ return false;
+ if (!RD->getIdentifier())
+ return true;
+ auto *TSpecial = dyn_cast<ClassTemplateSpecializationDecl>(RD);
+ if (!TSpecial)
+ return false;
+ return ReferencesAnonymousEntity(TSpecial->getTemplateArgs().asArray());
+}
+static bool ReferencesAnonymousEntity(ArrayRef<TemplateArgument> Args) {
+ return llvm::any_of(Args, [&](const TemplateArgument &TA) {
+ switch (TA.getKind()) {
+ case TemplateArgument::Pack:
+ return ReferencesAnonymousEntity(TA.getPackAsArray());
+ case TemplateArgument::Type: {
+ struct ReferencesAnonymous
+ : public RecursiveASTVisitor<ReferencesAnonymous> {
+ bool ReferencesAnonymous = false;
+ bool VisitRecordType(RecordType *RT) {
+ if (ReferencesAnonymousEntity(RT)) {
+ ReferencesAnonymous = true;
+ return false;
+ }
+ return true;
+ }
+ };
+ ReferencesAnonymous RT;
+ RT.TraverseType(TA.getAsType());
+ if (RT.ReferencesAnonymous)
+ return true;
+ break;
+ }
+ default:
+ break;
+ }
+ return false;
+ });
+}
namespace {
struct ReconstitutableType : public RecursiveASTVisitor<ReconstitutableType> {
bool Reconstitutable = true;
@@ -5002,16 +5048,8 @@ struct ReconstitutableType : public RecursiveASTVisitor<ReconstitutableType> {
Reconstitutable &= !isNoexceptExceptionSpec(FT->getExceptionSpecType());
return Reconstitutable;
}
- bool TraverseRecordType(RecordType *RT) {
- // Unnamed classes/lambdas can't be reconstituted due to a lack of column
- // info we produce in the DWARF, so we can't get Clang's full name back.
- // But so long as it's not one of those, it doesn't matter if some sub-type
- // of the record (a template parameter) can't be reconstituted - because the
- // un-reconstitutable type itself will carry its own name.
- const auto *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
- if (!RD)
- return true;
- if (RD->isLambda() || !RD->getIdentifier()) {
+ bool VisitRecordType(RecordType *RT) {
+ if (ReferencesAnonymousEntity(RT)) {
Reconstitutable = false;
return false;
}
diff --git a/clang/test/CodeGenCXX/debug-info-simple-template-names.cpp b/clang/test/CodeGenCXX/debug-info-simple-template-names.cpp
index 73a8f49967a7..344bd93020f6 100644
--- a/clang/test/CodeGenCXX/debug-info-simple-template-names.cpp
+++ b/clang/test/CodeGenCXX/debug-info-simple-template-names.cpp
@@ -48,9 +48,11 @@ void f() {
// since we don't emit the column number. Also lambdas and unnamed classes are
// ambiguous with each other - there's no DWARF that designates a lambda as
// anything other than another unnamed class/struct.
- auto A = [] {};
- f1<decltype(A)>();
- // CHECK: !DISubprogram(name: "f1<(lambda at {{.*}}debug-info-simple-template-names.cpp:[[# @LINE - 2]]:12)>",
+ auto Lambda = [] {};
+ f1<decltype(Lambda)>();
+ // CHECK: !DISubprogram(name: "f1<(lambda at {{.*}}debug-info-simple-template-names.cpp:[[# @LINE - 2]]:17)>",
+ f1<t1<t1<decltype(Lambda)>>>();
+ // CHECK: !DISubprogram(name: "f1<t1<t1<(lambda at {{.*}}> > >",
struct {
} unnamed_struct;
f1<decltype(unnamed_struct)>();
diff --git a/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names.cpp b/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names.cpp
index 61ac76db832c..d608039959df 100644
--- a/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names.cpp
+++ b/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names.cpp
@@ -216,6 +216,7 @@ int main() {
f1<t3<t3<int>>>();
f1<decltype(L)>();
t3<decltype(L)> v1;
+ f1<t3<t3<decltype(L)>>>();
f1<int(float)>();
f1<void(...)>();
f1<void(int, ...)>();
diff --git a/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names_noncanonical_type_units.cpp b/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names_noncanonical_type_units.cpp
new file mode 100644
index 000000000000..65c6bba6746f
--- /dev/null
+++ b/cross-project-tests/debuginfo-tests/clang_llvm_roundtrip/simplified_template_names_noncanonical_type_units.cpp
@@ -0,0 +1,40 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: mkdir %t/incl
+// RUN: mv %t/header.h %t/incl/header.h
+// RUN: cd %t
+// RUN: %clang %target_itanium_abi_host_triple -g -o %t/a.out \
+// RUN: -Xclang -gsimple-template-names=mangled \
+// RUN: -Xclang -debug-forward-template-params \
+// RUN: -std=c++20 -fdebug-types-section -I incl a.cpp b.cpp
+// RUN: llvm-dwarfdump --verify %t/a.out
+
+//--- header.h
+template <typename T> struct t1 {};
+inline auto f1() {
+ auto T = [] {};
+ t1<decltype(T)> v;
+ return v;
+}
+inline auto f2() {
+ struct {
+ } T;
+ t1<decltype(T)> v;
+ return v;
+}
+void a();
+//--- a.cpp
+#include "incl/header.h"
+template <typename T> void ft() {}
+void a() {
+ ft<decltype(f1())>();
+ ft<decltype(f2())>();
+}
+//--- b.cpp
+#include "header.h"
+template <typename T> void ft() {}
+int main() {
+ a();
+ ft<decltype(f1())>();
+ ft<decltype(f2())>();
+}
--
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