[clang] [clang] Adding an API to create a `CXStringSet` from a Vector of `StringRef`s (PR #136773)

[Qiongsi Wu via cfe-commits]

https://github.com/qiongsiwu updated https://github.com/llvm/llvm-project/pull/136773

>From 7f39ebcc34fe3f40c2554ff7fa93baca5b4634a0 Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qiongsi_wu at apple.com>
Date: Tue, 22 Apr 2025 14:17:15 -0700
Subject: [PATCH 1/4] Adding CXStringSet *createSet that takes a vector of
 StringRef as input.

---
 clang/tools/libclang/CXString.cpp | 10 +++++++++-
 clang/tools/libclang/CXString.h   |  3 +++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/clang/tools/libclang/CXString.cpp b/clang/tools/libclang/CXString.cpp
index aaa8f8eeb67a1..7e46fcc3b8e69 100644
--- a/clang/tools/libclang/CXString.cpp
+++ b/clang/tools/libclang/CXString.cpp
@@ -107,7 +107,8 @@ CXString createCXString(CXStringBuf *buf) {
   return Str;
 }
 
-CXStringSet *createSet(const std::vector<std::string> &Strings) {
+template <typename StringTy>
+static CXStringSet *createSetImpl(const std::vector<StringTy> &Strings) {
   CXStringSet *Set = new CXStringSet;
   Set->Count = Strings.size();
   Set->Strings = new CXString[Set->Count];
@@ -116,6 +117,13 @@ CXStringSet *createSet(const std::vector<std::string> &Strings) {
   return Set;
 }
 
+CXStringSet *createSet(const std::vector<std::string> &Strings) {
+  return createSetImpl(Strings);
+}
+
+CXStringSet *createSet(const std::vector<StringRef> &Strings) {
+  return createSetImpl(Strings);
+}
 
 //===----------------------------------------------------------------------===//
 // String pools.
diff --git a/clang/tools/libclang/CXString.h b/clang/tools/libclang/CXString.h
index 809bdec3d677f..24c4092a9a2c0 100644
--- a/clang/tools/libclang/CXString.h
+++ b/clang/tools/libclang/CXString.h
@@ -67,7 +67,10 @@ CXString createRef(std::string String) = delete;
 /// Create a CXString object that is backed by a string buffer.
 CXString createCXString(CXStringBuf *buf);
 
+/// Create a CXStringSet object owns the strings. Such an object should be
+/// disposed with clang_disposeStringSet.
 CXStringSet *createSet(const std::vector<std::string> &Strings);
+CXStringSet *createSet(const std::vector<StringRef> &Strings);
 
 /// A string pool used for fast allocation/deallocation of strings.
 class CXStringPool {

>From 506c91d22bc6284a64f31a06a340110d5847def1 Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qiongsi_wu at apple.com>
Date: Tue, 22 Apr 2025 16:19:57 -0700
Subject: [PATCH 2/4] Revise so that we can create an interface to avoid string
 copying.

---
 clang/tools/libclang/CXString.cpp | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/clang/tools/libclang/CXString.cpp b/clang/tools/libclang/CXString.cpp
index 7e46fcc3b8e69..edfbe354c3331 100644
--- a/clang/tools/libclang/CXString.cpp
+++ b/clang/tools/libclang/CXString.cpp
@@ -107,22 +107,27 @@ CXString createCXString(CXStringBuf *buf) {
   return Str;
 }
 
-template <typename StringTy>
-static CXStringSet *createSetImpl(const std::vector<StringTy> &Strings) {
+template <typename StringTy, bool Copy>
+static CXStringSet *createSetImpl(ArrayRef<StringTy> Strings) {
   CXStringSet *Set = new CXStringSet;
   Set->Count = Strings.size();
   Set->Strings = new CXString[Set->Count];
-  for (unsigned SI = 0, SE = Set->Count; SI < SE; ++SI)
-    Set->Strings[SI] = createDup(Strings[SI]);
+  for (unsigned SI = 0, SE = Set->Count; SI < SE; ++SI) {
+    if constexpr (Copy) {
+      Set->Strings[SI] = createDup(Strings[SI]);
+    } else {
+      Set->Strings[SI] = createRef(Strings[SI]);
+    }
+  }
   return Set;
 }
 
 CXStringSet *createSet(const std::vector<std::string> &Strings) {
-  return createSetImpl(Strings);
+  return createSetImpl<std::string, true>(ArrayRef<std::string>(Strings));
 }
 
-CXStringSet *createSet(const std::vector<StringRef> &Strings) {
-  return createSetImpl(Strings);
+CXStringSet *createRefSet(ArrayRef<StringRef> Strings) {
+  return createSetImpl<StringRef, false>(Strings);
 }
 
 //===----------------------------------------------------------------------===//

>From f3df9577b152794708056c379c08bbe306d86e6e Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qiongsi_wu at apple.com>
Date: Tue, 22 Apr 2025 16:22:25 -0700
Subject: [PATCH 3/4] Fix function prototype.

---
 clang/tools/libclang/CXString.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/tools/libclang/CXString.h b/clang/tools/libclang/CXString.h
index 24c4092a9a2c0..4662ab75f1286 100644
--- a/clang/tools/libclang/CXString.h
+++ b/clang/tools/libclang/CXString.h
@@ -70,7 +70,7 @@ CXString createCXString(CXStringBuf *buf);
 /// Create a CXStringSet object owns the strings. Such an object should be
 /// disposed with clang_disposeStringSet.
 CXStringSet *createSet(const std::vector<std::string> &Strings);
-CXStringSet *createSet(const std::vector<StringRef> &Strings);
+CXStringSet *createRefSet(ArrayRef<StringRef> Strings);
 
 /// A string pool used for fast allocation/deallocation of strings.
 class CXStringPool {

>From ea4e8c60a99af5c00c6647bc0ff6d22b05bb508b Mon Sep 17 00:00:00 2001
From: Qiongsi Wu <qiongsi_wu at apple.com>
Date: Wed, 23 Apr 2025 08:28:24 -0700
Subject: [PATCH 4/4] Updating comments.

---
 clang/tools/libclang/CXString.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/clang/tools/libclang/CXString.h b/clang/tools/libclang/CXString.h
index 4662ab75f1286..c20b68a83c29e 100644
--- a/clang/tools/libclang/CXString.h
+++ b/clang/tools/libclang/CXString.h
@@ -67,9 +67,12 @@ CXString createRef(std::string String) = delete;
 /// Create a CXString object that is backed by a string buffer.
 CXString createCXString(CXStringBuf *buf);
 
-/// Create a CXStringSet object owns the strings. Such an object should be
+/// Create a CXStringSet object that owns the strings. Such an object should be
 /// disposed with clang_disposeStringSet.
 CXStringSet *createSet(const std::vector<std::string> &Strings);
+
+/// Create a CXStringSet object that does not own the strings. Such an object
+/// should still be disposed with clang_disposeStringSet.
 CXStringSet *createRefSet(ArrayRef<StringRef> Strings);
 
 /// A string pool used for fast allocation/deallocation of strings.
@@ -108,4 +111,3 @@ static inline StringRef getContents(const CXUnsavedFile &UF) {
 }
 
 #endif
-