[clang] [Tooling/Inclusion] Avoid narrowing-conversions in macro expansion (PR #72664)

[Krzysztof Parzyszek via cfe-commits]

https://github.com/kparzysz created https://github.com/llvm/llvm-project/pull/72664

```
clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp:144:65: warning: narrowing conversion of ‘llvm::StringRef(((const char*)"std::experimental::filesystem::")).llvm::StringRef::size()’ from ‘size_t’ {aka ‘long un signed int’} to ‘unsigned int’ [-Wnarrowing]
  144 | #define SYMBOL(Name, NS, Header) {#NS #Name, StringRef(#NS).size(), #Header},
      |                                              ~~~~~~~~~~~~~~~~~~~^~
clang/lib/Tooling/Inclusions/Stdlib/StdTsSymbolMap.inc:51:1: note: in expansion of macro ‘SYMBOL’
   51 | SYMBOL(temp_directory_path, std::experimental::filesystem::, <experimental/filesystem>)
      | ^~~~~~
```

>From c720fc96d8b92e5eccdd594c2b3d6bbc71d81455 Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <Krzysztof.Parzyszek at amd.com>
Date: Fri, 17 Nov 2023 09:18:02 -0600
Subject: [PATCH] [Tooling/Inclusion] Avoid narrowing-conversions in macro
 expansion
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clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp:144:65: warning:
 narrowing conversion of ‘llvm::StringRef(((const char*)"std::experiment
al::filesystem::")).llvm::StringRef::size()’ from ‘size_t’ {aka ‘long un
signed int’} to ‘unsigned int’ [-Wnarrowing]
  144 | #define SYMBOL(Name, NS, Header) {#NS #Name, StringRef(#NS).size
(), #Header},
      |                                              ~~~~~~~~~~~~~~~~~~~
^~
clang/lib/Tooling/Inclusions/Stdlib/StdTsSymbolMap.inc:51:1: note: in ex
pansion of macro ‘SYMBOL’
   51 | SYMBOL(temp_directory_path, std::experimental::filesystem::, <ex
perimental/filesystem>)
      | ^~~~~~
---
 clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp b/clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp
index 03f61d33e1f26e7..adf1b230ff03181 100644
--- a/clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp
+++ b/clang/lib/Tooling/Inclusions/Stdlib/StandardLibrary.cpp
@@ -141,7 +141,9 @@ static int initialize(Lang Language) {
     unsigned NSLen;
     const char *HeaderName;
   };
-#define SYMBOL(Name, NS, Header) {#NS #Name, StringRef(#NS).size(), #Header},
+#define SYMBOL(Name, NS, Header)                                               \
+  {#NS #Name, static_cast<decltype(Symbol::NSLen)>(StringRef(#NS).size()),     \
+   #Header},
   switch (Language) {
   case Lang::C: {
     static constexpr Symbol CSymbols[] = {