https://github.com/falbrechtskirchinger created
https://github.com/llvm/llvm-project/pull/110496
Note: This patch is based on the assumption, that an assertion causing a crash
in clangd, is incorrect. Alternatively, the true error may lie elsewhere,
possibly in ´Sema::BuildTypeConstraint`/`Sema::AttachTypeConstraint`. Someone
with more experience is needed to make that call.
Commit message follows.
<hr />
The ASTWriter currently assumes template type constraints to be initialized
((bool)getTypeConstraint() == hasTypeConstraint()). The attached test case
presents a scenario where that is not the case.
This patch removes the assumption and adds another boolean to the
serialization, to explicitly encode whether the type constraint has been
initialized.
Fixes #99036.
Fixes #109354.
>From 296cc1b1389cc1a7aff4f5a84a48b6db4fe9e59a Mon Sep 17 00:00:00 2001
From: Florian Albrechtskirchinger <falbrechtskirchin...@gmail.com>
Date: Mon, 30 Sep 2024 12:58:15 +0200
Subject: [PATCH] [clangd] [AST] Handle uninitialized type constraints
The ASTWriter currently assumes template type constraints to be
initialized ((bool)getTypeConstraint() == hasTypeConstraint()).
The attached test case presents a scenario where that is not the case.
This patch removes the assumption and adds another boolean to the
serialization, to explicitly encode whether the type constraint has been
initialized.
Fixes #99036.
Fixes #109354.
---
clang-tools-extra/clangd/test/GH99036.test | 29 ++++++++++++++++++++++
clang/lib/Serialization/ASTReaderDecl.cpp | 2 +-
clang/lib/Serialization/ASTWriterDecl.cpp | 5 ++--
3 files changed, 33 insertions(+), 3 deletions(-)
create mode 100644 clang-tools-extra/clangd/test/GH99036.test
diff --git a/clang-tools-extra/clangd/test/GH99036.test
b/clang-tools-extra/clangd/test/GH99036.test
new file mode 100644
index 00000000000000..64ebe4c75a999d
--- /dev/null
+++ b/clang-tools-extra/clangd/test/GH99036.test
@@ -0,0 +1,29 @@
+# RUN: rm -rf %t
+# RUN: mkdir -p %t
+# RUN: split-file %s %t
+#
+# RUN: not clangd --check=%t/main.cpp 2>&1 | FileCheck -strict-whitespace %s
+#
+# CHECK: Loaded compilation database
+# CHECK-NEXT: Compile command inferred from main.cpp is:
+# CHECK: Indexing headers...
+# CHECK-NEXT: [unknown_typename] Line 1: in included file: unknown type name
'_Up'
+# CHECK: All checks completed, 1 errors
+
+#--- header.h
+template<_Up>
+concept __decayed_same_as;
+template<__decayed_same_as>
+partial_ordering operator0
+
+#--- main.cpp
+#include "header.h"
+
+#--- compile_commands.json
+[
+ {
+ "directory": "/",
+ "command": "c++ -std=c++20",
+ "file": "main.cpp"
+ }
+]
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp
b/clang/lib/Serialization/ASTReaderDecl.cpp
index 7cead2728ca938..90783963934bb0 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2674,7 +2674,7 @@ void
ASTDeclReader::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
D->setDeclaredWithTypename(Record.readInt());
- if (D->hasTypeConstraint()) {
+ if (Record.readBool() && D->hasTypeConstraint()) {
ConceptReference *CR = nullptr;
if (Record.readBool())
CR = Record.readConceptReference();
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp
b/clang/lib/Serialization/ASTWriterDecl.cpp
index b71684569609ac..1c9898c042cd4b 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -1899,7 +1899,7 @@ void
ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
Record.push_back(D->wasDeclaredWithTypename());
const TypeConstraint *TC = D->getTypeConstraint();
- assert((bool)TC == D->hasTypeConstraint());
+ Record.push_back(TC != nullptr); // reflects TypeConstraintInitialized
if (TC) {
auto *CR = TC->getConceptReference();
Record.push_back(CR != nullptr);
@@ -1917,7 +1917,7 @@ void
ASTDeclWriter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
if (OwnsDefaultArg)
Record.AddTemplateArgumentLoc(D->getDefaultArgument());
- if (!TC && !OwnsDefaultArg &&
+ if (!D->hasTypeConstraint() && !OwnsDefaultArg &&
D->getDeclContext() == D->getLexicalDeclContext() &&
!D->isInvalidDecl() && !D->hasAttrs() &&
!D->isTopLevelDeclInObjCContainer() && !D->isImplicit() &&
@@ -2580,6 +2580,7 @@ void ASTWriter::WriteDeclAbbrevs() {
// TemplateTypeParmDecl
Abv->Add(
BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // wasDeclaredWithTypename
+ Abv->Add(BitCodeAbbrevOp(0)); // TypeConstraintInitialized
Abv->Add(BitCodeAbbrevOp(0)); // OwnsDefaultArg
DeclTemplateTypeParmAbbrev = Stream.EmitAbbrev(std::move(Abv));
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