[llvm] [NFC][LLVM][ADT] Change a few `const StringRef &` arguments to value (PR #163994)

[Rahul Joshi via llvm-commits]

https://github.com/jurahul updated https://github.com/llvm/llvm-project/pull/163994

>From 067e30dc8d018a3632ab2a8a9c422d02c7d768e1 Mon Sep 17 00:00:00 2001
From: Rahul Joshi <rjoshi at nvidia.com>
Date: Fri, 17 Oct 2025 09:55:33 -0700
Subject: [PATCH 1/2] [NFC][LLVM][ADT] Change a few `const StringRef &`
 arguments to value

Per LLVM Programmer's Manual, StringRef should always be passed by
value. Enforcing this for a few ADT functions.
---
 llvm/include/llvm/ADT/STLExtras.h |  6 +++---
 llvm/include/llvm/ADT/Twine.h     | 10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 658f26249122a..3de09131f8c03 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/STLForwardCompat.h"
 #include "llvm/ADT/STLFunctionalExtras.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Config/abi-breaking.h"
@@ -2215,13 +2216,12 @@ inline void interleave(const Container &c, UnaryFunctor each_fn,
 template <typename Container, typename UnaryFunctor, typename StreamT,
           typename T = detail::ValueOfRange<Container>>
 inline void interleave(const Container &c, StreamT &os, UnaryFunctor each_fn,
-                       const StringRef &separator) {
+                       StringRef separator) {
   interleave(adl_begin(c), adl_end(c), each_fn, [&] { os << separator; });
 }
 template <typename Container, typename StreamT,
           typename T = detail::ValueOfRange<Container>>
-inline void interleave(const Container &c, StreamT &os,
-                       const StringRef &separator) {
+inline void interleave(const Container &c, StreamT &os, StringRef separator) {
   interleave(
       c, os, [&](const T &a) { os << a; }, separator);
 }
diff --git a/llvm/include/llvm/ADT/Twine.h b/llvm/include/llvm/ADT/Twine.h
index d9f9c0f0d5d9c..e3b4d5e26fa17 100644
--- a/llvm/include/llvm/ADT/Twine.h
+++ b/llvm/include/llvm/ADT/Twine.h
@@ -285,7 +285,7 @@ class Twine {
   }
 
   /// Construct from a StringRef.
-  /*implicit*/ Twine(const StringRef &Str) : LHSKind(PtrAndLengthKind) {
+  /*implicit*/ Twine(StringRef Str) : LHSKind(PtrAndLengthKind) {
     LHS.ptrAndLength.ptr = Str.data();
     LHS.ptrAndLength.length = Str.size();
     assert(isValid() && "Invalid twine!");
@@ -352,7 +352,7 @@ class Twine {
   // right thing. Yet.
 
   /// Construct as the concatenation of a C string and a StringRef.
-  /*implicit*/ Twine(const char *LHS, const StringRef &RHS)
+  /*implicit*/ Twine(const char *LHS, StringRef RHS)
       : LHSKind(CStringKind), RHSKind(PtrAndLengthKind) {
     this->LHS.cString = LHS;
     this->RHS.ptrAndLength.ptr = RHS.data();
@@ -361,7 +361,7 @@ class Twine {
   }
 
   /// Construct as the concatenation of a StringRef and a C string.
-  /*implicit*/ Twine(const StringRef &LHS, const char *RHS)
+  /*implicit*/ Twine(StringRef LHS, const char *RHS)
       : LHSKind(PtrAndLengthKind), RHSKind(CStringKind) {
     this->LHS.ptrAndLength.ptr = LHS.data();
     this->LHS.ptrAndLength.length = LHS.size();
@@ -530,14 +530,14 @@ inline Twine operator+(const Twine &LHS, const Twine &RHS) {
 /// Additional overload to guarantee simplified codegen; this is equivalent to
 /// concat().
 
-inline Twine operator+(const char *LHS, const StringRef &RHS) {
+inline Twine operator+(const char *LHS, StringRef RHS) {
   return Twine(LHS, RHS);
 }
 
 /// Additional overload to guarantee simplified codegen; this is equivalent to
 /// concat().
 
-inline Twine operator+(const StringRef &LHS, const char *RHS) {
+inline Twine operator+(StringRef LHS, const char *RHS) {
   return Twine(LHS, RHS);
 }
 

>From f6c7f8e1e2a3fe4e532d8a88fa67c197baaf9efc Mon Sep 17 00:00:00 2001
From: Rahul Joshi <rjoshi at nvidia.com>
Date: Tue, 21 Oct 2025 11:16:00 -0700
Subject: [PATCH 2/2] Undo STLExtras

---
 llvm/include/llvm/ADT/STLExtras.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 3de09131f8c03..658f26249122a 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -21,7 +21,6 @@
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/STLForwardCompat.h"
 #include "llvm/ADT/STLFunctionalExtras.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Config/abi-breaking.h"
@@ -2216,12 +2215,13 @@ inline void interleave(const Container &c, UnaryFunctor each_fn,
 template <typename Container, typename UnaryFunctor, typename StreamT,
           typename T = detail::ValueOfRange<Container>>
 inline void interleave(const Container &c, StreamT &os, UnaryFunctor each_fn,
-                       StringRef separator) {
+                       const StringRef &separator) {
   interleave(adl_begin(c), adl_end(c), each_fn, [&] { os << separator; });
 }
 template <typename Container, typename StreamT,
           typename T = detail::ValueOfRange<Container>>
-inline void interleave(const Container &c, StreamT &os, StringRef separator) {
+inline void interleave(const Container &c, StreamT &os,
+                       const StringRef &separator) {
   interleave(
       c, os, [&](const T &a) { os << a; }, separator);
 }