[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-17 Thread LLVM Continuous Integration via cfe-commits

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-x86_64-windows` 
running on `minipc-ryzen-win` while building `clang` at step 8 
"test-build-unified-tree-check-flang-rt".

Full details are available at: 
https://lab.llvm.org/buildbot/#/builders/166/builds/1158


Here is the relevant piece of the build log for the reference

```
Step 8 (test-build-unified-tree-check-flang-rt) failure: test (failure)
 TEST 'flang-rt-OldUnit :: Runtime/RuntimeTests.exe' FAILED 

[==] Running 225 tests from 54 test suites.

[--] Global test environment set-up.

[--] 4 tests from AllocatableTest

[ RUN  ] AllocatableTest.MoveAlloc

[   OK ] AllocatableTest.MoveAlloc (0 ms)

[ RUN  ] AllocatableTest.AllocateFromScalarSource

[   OK ] AllocatableTest.AllocateFromScalarSource (0 ms)

[ RUN  ] AllocatableTest.AllocateSourceZeroSize

[   OK ] AllocatableTest.AllocateSourceZeroSize (0 ms)

[ RUN  ] AllocatableTest.DoubleAllocation

[   OK ] AllocatableTest.DoubleAllocation (0 ms)

[--] 4 tests from AllocatableTest (0 ms total)



[--] 3 tests from ArrayConstructor

[ RUN  ] ArrayConstructor.Basic

[   OK ] ArrayConstructor.Basic (0 ms)

[ RUN  ] ArrayConstructor.Character

[   OK ] ArrayConstructor.Character (0 ms)

[ RUN  ] ArrayConstructor.CharacterRuntimeCheck

[   OK ] ArrayConstructor.CharacterRuntimeCheck (72 ms)

[--] 3 tests from ArrayConstructor (72 ms total)



[--] 1 test from BufferTests

[ RUN  ] BufferTests.TestFrameBufferReadAndWrite

[   OK ] BufferTests.TestFrameBufferReadAndWrite (0 ms)
...

```



https://github.com/llvm/llvm-project/pull/135887
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[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-17 Thread Volodymyr Sapsai via cfe-commits

https://github.com/vsapsai closed 
https://github.com/llvm/llvm-project/pull/135887
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[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-16 Thread Volodymyr Sapsai via cfe-commits

https://github.com/vsapsai updated 
https://github.com/llvm/llvm-project/pull/135887

>From d944252ce2f08d1522f7297e4d7f9a7b730db180 Mon Sep 17 00:00:00 2001
From: Volodymyr Sapsai 
Date: Tue, 15 Apr 2025 16:34:47 -0700
Subject: [PATCH 1/2] [Modules] Fix the inconsistency of which `Decl` should be
 serialized for an identifier.

Fixes the assertion failure
> Assertion failed: (DeclIDs.contains(D) && "Declaration not emitted!"), 
> function getDeclID, file ASTWriter.cpp, line 6873.

We prepare to serialize a `Decl` by adding it to `DeclIDs` in
`ASTWriter::GetDeclRef`. But the checks before this call aren't the same as
when we are actually serializing a `Decl` in `ASTIdentifierTableTrait::EmitData`
and `ASTWriter::WriteIdentifierTable`. That's how we can end up serializing
a `Decl` not present in `DeclIDs` and hitting the assertion. With the assertions
disabled clang crashes when trying to use a deserialized null `Decl`.

Fix by making the code checks before `ASTWriter::GetDeclRef` call similar
to those we have before the serialization.

rdar://139319683
---
 clang/include/clang/Serialization/ASTWriter.h |   1 +
 clang/lib/Serialization/ASTWriter.cpp |  11 +-
 clang/test/Modules/non-modular-decl-use.c | 100 ++
 3 files changed, 109 insertions(+), 3 deletions(-)
 create mode 100644 clang/test/Modules/non-modular-decl-use.c

diff --git a/clang/include/clang/Serialization/ASTWriter.h 
b/clang/include/clang/Serialization/ASTWriter.h
index bdf3aca0637c8..5075232596cea 100644
--- a/clang/include/clang/Serialization/ASTWriter.h
+++ b/clang/include/clang/Serialization/ASTWriter.h
@@ -224,6 +224,7 @@ class ASTWriter : public ASTDeserializationListener,
   /// discovery) and start at 2. 1 is reserved for the translation
   /// unit, while 0 is reserved for NULL.
   llvm::DenseMap DeclIDs;
+  // TMP: ^ DeclIDs type for reference
 
   /// Set of predefined decls. This is a helper data to determine if a decl
   /// is predefined. It should be more clear and safer to query the set
diff --git a/clang/lib/Serialization/ASTWriter.cpp 
b/clang/lib/Serialization/ASTWriter.cpp
index 95b5718f1d140..c9db69b3b784b 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3925,6 +3925,7 @@ class ASTIdentifierTableTrait {
   // Only emit declarations that aren't from a chained PCH, though.
   SmallVector Decls(IdResolver->decls(II));
   for (NamedDecl *D : llvm::reverse(Decls))
+// TMP: corresponding `getDeclForLocalLookup` call
 LE.write((DeclID)Writer.getDeclID(
 getDeclForLocalLookup(PP.getLangOpts(), D)));
 }
@@ -3969,6 +3970,7 @@ void ASTWriter::WriteIdentifierTable(Preprocessor &PP,
   if (isLocalIdentifierID(ID) || II->hasChangedSinceDeserialization() ||
   (Trait.needDecls() &&
II->hasFETokenInfoChangedSinceDeserialization()))
+// TMP: ^ corresponding `hasFETokenInfoChangedSinceDeserialization` 
call
 Generator.insert(II, ID, Trait);
 }
 
@@ -5664,14 +5666,16 @@ void ASTWriter::PrepareWritingSpecialDecls(Sema 
&SemaRef) {
 llvm::SmallVector IIs;
 for (const auto &ID : SemaRef.PP.getIdentifierTable()) {
   const IdentifierInfo *II = ID.second;
-  if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization())
+  if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization() ||
+  II->hasFETokenInfoChangedSinceDeserialization())
 IIs.push_back(II);
 }
 // Sort the identifiers to visit based on their name.
 llvm::sort(IIs, llvm::deref>());
+const LangOptions &LangOpts = getLangOpts();
 for (const IdentifierInfo *II : IIs)
-  for (const Decl *D : SemaRef.IdResolver.decls(II))
-GetDeclRef(D);
+  for (NamedDecl *D : SemaRef.IdResolver.decls(II))
+GetDeclRef(getDeclForLocalLookup(LangOpts, D));
   }
 
   // Write all of the DeclsToCheckForDeferredDiags.
@@ -6845,6 +6849,7 @@ LocalDeclID ASTWriter::GetDeclRef(const Decl *D) {
   }
 
   assert(!(reinterpret_cast(D) & 0x01) && "Invalid decl pointer");
+  // TMP: adding D to DeclIDs
   LocalDeclID &ID = DeclIDs[D];
   if (ID.isInvalid()) {
 if (DoneWritingDeclsAndTypes) {
diff --git a/clang/test/Modules/non-modular-decl-use.c 
b/clang/test/Modules/non-modular-decl-use.c
new file mode 100644
index 0..1bd87bf284620
--- /dev/null
+++ b/clang/test/Modules/non-modular-decl-use.c
@@ -0,0 +1,100 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %clang_cc1 -fsyntax-only -I %t/include %t/test.c \
+// RUN:-fmodules -fimplicit-module-maps 
-fmodules-cache-path=%t/modules.cache
+
+// Test when a decl is present in multiple modules through an inclusion of
+// a non-modular header. Make sure such decl is serialized correctly and can be
+// used after deserialization.
+
+//--- include/non-modular.h
+#ifndef NON_MODULAR_H
+#define NON_MODULAR_H
+
+union TestUnion {
+  int x;
+  float y;
+};
+
+struct ReferenceUnion1 {

[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-16 Thread Jan Svoboda via cfe-commits

https://github.com/jansvoboda11 approved this pull request.


https://github.com/llvm/llvm-project/pull/135887
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[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-15 Thread Chuanqi Xu via cfe-commits

https://github.com/ChuanqiXu9 approved this pull request.

LGTM

https://github.com/llvm/llvm-project/pull/135887
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[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-15 Thread Volodymyr Sapsai via cfe-commits

vsapsai wrote:

cc @zygoloid as he has touched this code 10 years ago.

https://github.com/llvm/llvm-project/pull/135887
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[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-15 Thread Volodymyr Sapsai via cfe-commits


@@ -224,6 +224,7 @@ class ASTWriter : public ASTDeserializationListener,
   /// discovery) and start at 2. 1 is reserved for the translation
   /// unit, while 0 is reserved for NULL.
   llvm::DenseMap DeclIDs;
+  // TMP: ^ DeclIDs type for reference

vsapsai wrote:

I will remove all TMP comments before committing. Using this to simplify the 
review by pulling in the pointers to the relevant code.

https://github.com/llvm/llvm-project/pull/135887
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[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-15 Thread via cfe-commits

llvmbot wrote:



@llvm/pr-subscribers-clang-modules

@llvm/pr-subscribers-clang

Author: Volodymyr Sapsai (vsapsai)


Changes

Fixes the assertion failure
> Assertion failed: (DeclIDs.contains(D) && "Declaration not 
emitted!"), function getDeclID, file ASTWriter.cpp, line 6873.

We prepare to serialize a `Decl` by adding it to `DeclIDs` in 
`ASTWriter::GetDeclRef`. But the checks before this call aren't the same as 
when we are actually serializing a `Decl` in 
`ASTIdentifierTableTrait::EmitData` and `ASTWriter::WriteIdentifierTable`. 
That's how we can end up serializing a `Decl` not present in `DeclIDs` and 
hitting the assertion. With the assertions disabled clang crashes when trying 
to use a deserialized null `Decl`.

Fix by making the code checks before `ASTWriter::GetDeclRef` call similar to 
those we have before the serialization.

rdar://139319683

---
Full diff: https://github.com/llvm/llvm-project/pull/135887.diff


3 Files Affected:

- (modified) clang/include/clang/Serialization/ASTWriter.h (+1) 
- (modified) clang/lib/Serialization/ASTWriter.cpp (+8-3) 
- (added) clang/test/Modules/non-modular-decl-use.c (+100) 


``diff
diff --git a/clang/include/clang/Serialization/ASTWriter.h 
b/clang/include/clang/Serialization/ASTWriter.h
index bdf3aca0637c8..5075232596cea 100644
--- a/clang/include/clang/Serialization/ASTWriter.h
+++ b/clang/include/clang/Serialization/ASTWriter.h
@@ -224,6 +224,7 @@ class ASTWriter : public ASTDeserializationListener,
   /// discovery) and start at 2. 1 is reserved for the translation
   /// unit, while 0 is reserved for NULL.
   llvm::DenseMap DeclIDs;
+  // TMP: ^ DeclIDs type for reference
 
   /// Set of predefined decls. This is a helper data to determine if a decl
   /// is predefined. It should be more clear and safer to query the set
diff --git a/clang/lib/Serialization/ASTWriter.cpp 
b/clang/lib/Serialization/ASTWriter.cpp
index 95b5718f1d140..c9db69b3b784b 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3925,6 +3925,7 @@ class ASTIdentifierTableTrait {
   // Only emit declarations that aren't from a chained PCH, though.
   SmallVector Decls(IdResolver->decls(II));
   for (NamedDecl *D : llvm::reverse(Decls))
+// TMP: corresponding `getDeclForLocalLookup` call
 LE.write((DeclID)Writer.getDeclID(
 getDeclForLocalLookup(PP.getLangOpts(), D)));
 }
@@ -3969,6 +3970,7 @@ void ASTWriter::WriteIdentifierTable(Preprocessor &PP,
   if (isLocalIdentifierID(ID) || II->hasChangedSinceDeserialization() ||
   (Trait.needDecls() &&
II->hasFETokenInfoChangedSinceDeserialization()))
+// TMP: ^ corresponding `hasFETokenInfoChangedSinceDeserialization` 
call
 Generator.insert(II, ID, Trait);
 }
 
@@ -5664,14 +5666,16 @@ void ASTWriter::PrepareWritingSpecialDecls(Sema 
&SemaRef) {
 llvm::SmallVector IIs;
 for (const auto &ID : SemaRef.PP.getIdentifierTable()) {
   const IdentifierInfo *II = ID.second;
-  if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization())
+  if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization() ||
+  II->hasFETokenInfoChangedSinceDeserialization())
 IIs.push_back(II);
 }
 // Sort the identifiers to visit based on their name.
 llvm::sort(IIs, llvm::deref>());
+const LangOptions &LangOpts = getLangOpts();
 for (const IdentifierInfo *II : IIs)
-  for (const Decl *D : SemaRef.IdResolver.decls(II))
-GetDeclRef(D);
+  for (NamedDecl *D : SemaRef.IdResolver.decls(II))
+GetDeclRef(getDeclForLocalLookup(LangOpts, D));
   }
 
   // Write all of the DeclsToCheckForDeferredDiags.
@@ -6845,6 +6849,7 @@ LocalDeclID ASTWriter::GetDeclRef(const Decl *D) {
   }
 
   assert(!(reinterpret_cast(D) & 0x01) && "Invalid decl pointer");
+  // TMP: adding D to DeclIDs
   LocalDeclID &ID = DeclIDs[D];
   if (ID.isInvalid()) {
 if (DoneWritingDeclsAndTypes) {
diff --git a/clang/test/Modules/non-modular-decl-use.c 
b/clang/test/Modules/non-modular-decl-use.c
new file mode 100644
index 0..1bd87bf284620
--- /dev/null
+++ b/clang/test/Modules/non-modular-decl-use.c
@@ -0,0 +1,100 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %clang_cc1 -fsyntax-only -I %t/include %t/test.c \
+// RUN:-fmodules -fimplicit-module-maps 
-fmodules-cache-path=%t/modules.cache
+
+// Test when a decl is present in multiple modules through an inclusion of
+// a non-modular header. Make sure such decl is serialized correctly and can be
+// used after deserialization.
+
+//--- include/non-modular.h
+#ifndef NON_MODULAR_H
+#define NON_MODULAR_H
+
+union TestUnion {
+  int x;
+  float y;
+};
+
+struct ReferenceUnion1 {
+  union TestUnion name;
+  unsigned versionMajor;
+};
+struct ReferenceUnion2 {
+  union TestUnion name;
+  unsigned versionMinor;
+};
+
+// Test another kind of RecordDecl.
+struct TestStruct {
+  int p;
+

[clang] [Modules] Fix the inconsistency of which `Decl` should be serialized for an identifier. (PR #135887)

2025-04-15 Thread Volodymyr Sapsai via cfe-commits

https://github.com/vsapsai created 
https://github.com/llvm/llvm-project/pull/135887

Fixes the assertion failure
> Assertion failed: (DeclIDs.contains(D) && "Declaration not emitted!"), 
> function getDeclID, file ASTWriter.cpp, line 6873.

We prepare to serialize a `Decl` by adding it to `DeclIDs` in 
`ASTWriter::GetDeclRef`. But the checks before this call aren't the same as 
when we are actually serializing a `Decl` in 
`ASTIdentifierTableTrait::EmitData` and `ASTWriter::WriteIdentifierTable`. 
That's how we can end up serializing a `Decl` not present in `DeclIDs` and 
hitting the assertion. With the assertions disabled clang crashes when trying 
to use a deserialized null `Decl`.

Fix by making the code checks before `ASTWriter::GetDeclRef` call similar to 
those we have before the serialization.

rdar://139319683

>From d944252ce2f08d1522f7297e4d7f9a7b730db180 Mon Sep 17 00:00:00 2001
From: Volodymyr Sapsai 
Date: Tue, 15 Apr 2025 16:34:47 -0700
Subject: [PATCH] [Modules] Fix the inconsistency of which `Decl` should be
 serialized for an identifier.

Fixes the assertion failure
> Assertion failed: (DeclIDs.contains(D) && "Declaration not emitted!"), 
> function getDeclID, file ASTWriter.cpp, line 6873.

We prepare to serialize a `Decl` by adding it to `DeclIDs` in
`ASTWriter::GetDeclRef`. But the checks before this call aren't the same as
when we are actually serializing a `Decl` in `ASTIdentifierTableTrait::EmitData`
and `ASTWriter::WriteIdentifierTable`. That's how we can end up serializing
a `Decl` not present in `DeclIDs` and hitting the assertion. With the assertions
disabled clang crashes when trying to use a deserialized null `Decl`.

Fix by making the code checks before `ASTWriter::GetDeclRef` call similar
to those we have before the serialization.

rdar://139319683
---
 clang/include/clang/Serialization/ASTWriter.h |   1 +
 clang/lib/Serialization/ASTWriter.cpp |  11 +-
 clang/test/Modules/non-modular-decl-use.c | 100 ++
 3 files changed, 109 insertions(+), 3 deletions(-)
 create mode 100644 clang/test/Modules/non-modular-decl-use.c

diff --git a/clang/include/clang/Serialization/ASTWriter.h 
b/clang/include/clang/Serialization/ASTWriter.h
index bdf3aca0637c8..5075232596cea 100644
--- a/clang/include/clang/Serialization/ASTWriter.h
+++ b/clang/include/clang/Serialization/ASTWriter.h
@@ -224,6 +224,7 @@ class ASTWriter : public ASTDeserializationListener,
   /// discovery) and start at 2. 1 is reserved for the translation
   /// unit, while 0 is reserved for NULL.
   llvm::DenseMap DeclIDs;
+  // TMP: ^ DeclIDs type for reference
 
   /// Set of predefined decls. This is a helper data to determine if a decl
   /// is predefined. It should be more clear and safer to query the set
diff --git a/clang/lib/Serialization/ASTWriter.cpp 
b/clang/lib/Serialization/ASTWriter.cpp
index 95b5718f1d140..c9db69b3b784b 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3925,6 +3925,7 @@ class ASTIdentifierTableTrait {
   // Only emit declarations that aren't from a chained PCH, though.
   SmallVector Decls(IdResolver->decls(II));
   for (NamedDecl *D : llvm::reverse(Decls))
+// TMP: corresponding `getDeclForLocalLookup` call
 LE.write((DeclID)Writer.getDeclID(
 getDeclForLocalLookup(PP.getLangOpts(), D)));
 }
@@ -3969,6 +3970,7 @@ void ASTWriter::WriteIdentifierTable(Preprocessor &PP,
   if (isLocalIdentifierID(ID) || II->hasChangedSinceDeserialization() ||
   (Trait.needDecls() &&
II->hasFETokenInfoChangedSinceDeserialization()))
+// TMP: ^ corresponding `hasFETokenInfoChangedSinceDeserialization` 
call
 Generator.insert(II, ID, Trait);
 }
 
@@ -5664,14 +5666,16 @@ void ASTWriter::PrepareWritingSpecialDecls(Sema 
&SemaRef) {
 llvm::SmallVector IIs;
 for (const auto &ID : SemaRef.PP.getIdentifierTable()) {
   const IdentifierInfo *II = ID.second;
-  if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization())
+  if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization() ||
+  II->hasFETokenInfoChangedSinceDeserialization())
 IIs.push_back(II);
 }
 // Sort the identifiers to visit based on their name.
 llvm::sort(IIs, llvm::deref>());
+const LangOptions &LangOpts = getLangOpts();
 for (const IdentifierInfo *II : IIs)
-  for (const Decl *D : SemaRef.IdResolver.decls(II))
-GetDeclRef(D);
+  for (NamedDecl *D : SemaRef.IdResolver.decls(II))
+GetDeclRef(getDeclForLocalLookup(LangOpts, D));
   }
 
   // Write all of the DeclsToCheckForDeferredDiags.
@@ -6845,6 +6849,7 @@ LocalDeclID ASTWriter::GetDeclRef(const Decl *D) {
   }
 
   assert(!(reinterpret_cast(D) & 0x01) && "Invalid decl pointer");
+  // TMP: adding D to DeclIDs
   LocalDeclID &ID = DeclIDs[D];
   if (ID.isInvalid()) {
 if (DoneWritingDeclsAndTypes) {
diff --git a/clang/test/Modules/n