[clang-tools-extra] [clangd] Index reserved symbols from `*intrin.h` system headers (PR #119735)

[Nathan Ridge via cfe-commits]

https://github.com/HighCommander4 updated https://github.com/llvm/llvm-project/pull/119735

>From 04757e7d94ce5db11bb397accb0b1c0523d351ba Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Thu, 12 Dec 2024 12:15:32 -0600
Subject: [PATCH 1/3] [clangd] Index reserved symbols from `*intrin.h` system
 headers

Summary:
`clangd` intentionally suppresses indexing symbols from system headers
as these are likely implementation details the user does not want.
Howver, there are plenty of system headers that provide extensions that
we want to index, such as vector intrinsic headers. This patch adds an
extra check for these commonly-named '*intrin.h' headers. This is not
fully inclusive for all symbols the user might want, but it's a good
start.

Fixes: https://github.com/llvm/llvm-project/issues/118684
---
 clang-tools-extra/clangd/index/SymbolCollector.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/clang-tools-extra/clangd/index/SymbolCollector.cpp b/clang-tools-extra/clangd/index/SymbolCollector.cpp
index 81125dbb1aeafc..6d0af20e31260c 100644
--- a/clang-tools-extra/clangd/index/SymbolCollector.cpp
+++ b/clang-tools-extra/clangd/index/SymbolCollector.cpp
@@ -550,9 +550,14 @@ bool SymbolCollector::shouldCollectSymbol(const NamedDecl &ND,
   // Avoid indexing internal symbols in protobuf generated headers.
   if (isPrivateProtoDecl(ND))
     return false;
+
+  // System headers that end with `intrin.h` likely contain useful symbols.
   if (!Opts.CollectReserved &&
       (hasReservedName(ND) || hasReservedScope(*ND.getDeclContext())) &&
-      ASTCtx.getSourceManager().isInSystemHeader(ND.getLocation()))
+      ASTCtx.getSourceManager().isInSystemHeader(ND.getLocation()) &&
+      !ASTCtx.getSourceManager()
+           .getFilename(ND.getLocation())
+           .ends_with("intrin.h"))
     return false;
 
   return true;

>From d320cbbf576fce53f6e3df477c705dd0bf645fca Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Fri, 13 Dec 2024 07:19:23 -0600
Subject: [PATCH 2/3] test

---
 .../clangd/unittests/SymbolCollectorTests.cpp      | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp b/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
index e8088cb37fa51c..edc4e8aabe9a91 100644
--- a/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
@@ -2111,6 +2111,20 @@ TEST_F(SymbolCollectorTest, Reserved) {
   EXPECT_THAT(Symbols, IsEmpty());
 }
 
+TEST_F(SymbolCollectorTest, UnreservedIntrin) {
+  const char *Header = R"cpp(
+    #pragma once
+    void __foo();
+  )cpp";
+
+  TestHeaderName = "xintrin.h";
+  TestHeaderURI = URI::create(testPath(TestHeaderName)).toString();
+  InMemoryFileSystem = new llvm::vfs::InMemoryFileSystem;
+  CollectorOpts.FallbackDir = testRoot();
+  runSymbolCollector("#pragma GCC system_header\n" + std::string(Header), "");
+  EXPECT_THAT(Symbols, UnorderedElementsAre(qName("__foo")));
+}
+
 TEST_F(SymbolCollectorTest, Concepts) {
   const char *Header = R"cpp(
     template <class T>

>From f029a6216559f61f6e86ba62e9dff0e7b6c72c6b Mon Sep 17 00:00:00 2001
From: Nathan Ridge <zeratul976 at hotmail.com>
Date: Sun, 15 Dec 2024 02:51:19 -0500
Subject: [PATCH 3/3] tweak test name

---
 clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp b/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
index edc4e8aabe9a91..7a9703c744e93f 100644
--- a/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
@@ -2111,7 +2111,7 @@ TEST_F(SymbolCollectorTest, Reserved) {
   EXPECT_THAT(Symbols, IsEmpty());
 }
 
-TEST_F(SymbolCollectorTest, UnreservedIntrin) {
+TEST_F(SymbolCollectorTest, ReservedSymbolInIntrinsicHeader) {
   const char *Header = R"cpp(
     #pragma once
     void __foo();