[clang-tools-extra] [clangd] Forward --target to system include extraction (PR #65824)

[Matthew Mirvish via cfe-commits]

https://github.com/mincrmatt12 created https://github.com/llvm/llvm-project/pull/65824:

Some clang multilib configurations (such as the one currently used in the [beta ARM LLVM toolchain](https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm)) wind up only reporting the C++ include paths properly if they get passed the correct target. This patch ensures the `--target` (or `-target`) arguments are correctly sent to the queried driver.

>From dac47fee4d165870732bda7cc91cefd68d6b14e6 Mon Sep 17 00:00:00 2001
From: Matthew Mirvish <matthew at mm12.xyz>
Date: Fri, 8 Sep 2023 19:59:58 -0400
Subject: [PATCH] [clangd] Forward --target to system include extraction

Some clang multilib configurations (such as the one currently used in
the beta ARM LLVM toolchain) wind up only reporting the C++ include paths
properly if they get passed the correct target.
---
 clang-tools-extra/clangd/SystemIncludeExtractor.cpp  | 12 ++++++++++--
 .../clangd/test/system-include-extractor.test        |  5 +++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/clang-tools-extra/clangd/SystemIncludeExtractor.cpp b/clang-tools-extra/clangd/SystemIncludeExtractor.cpp
index ac99b220f6bd3f0..0c1ed810a37f7a4 100644
--- a/clang-tools-extra/clangd/SystemIncludeExtractor.cpp
+++ b/clang-tools-extra/clangd/SystemIncludeExtractor.cpp
@@ -87,12 +87,13 @@ struct DriverArgs {
   std::string Lang;
   std::string Sysroot;
   std::string ISysroot;
+  std::string Target;
 
   bool operator==(const DriverArgs &RHS) const {
     return std::tie(Driver, StandardIncludes, StandardCXXIncludes, Lang,
-                    Sysroot, ISysroot) ==
+                    Sysroot, ISysroot, Target) ==
            std::tie(RHS.Driver, RHS.StandardIncludes, RHS.StandardCXXIncludes,
-                    RHS.Lang, RHS.Sysroot, ISysroot);
+                    RHS.Lang, RHS.Sysroot, ISysroot, Target);
   }
 
   DriverArgs(const tooling::CompileCommand &Cmd, llvm::StringRef File) {
@@ -130,6 +131,11 @@ struct DriverArgs {
           ISysroot = Cmd.CommandLine[I + 1];
         else
           ISysroot = Arg.str();
+      } else if (Arg.consume_front("--target=")) {
+        Target = Arg.str();
+      } else if (Arg.consume_front("-target")) {
+        if (Arg.empty() && I + 1 < E)
+          Target = Cmd.CommandLine[I + 1];
       }
     }
 
@@ -167,6 +173,8 @@ struct DriverArgs {
       Args.append({"--sysroot", Sysroot});
     if (!ISysroot.empty())
       Args.append({"-isysroot", ISysroot});
+    if (!Target.empty())
+      Args.append({"-target", Target});
     return Args;
   }
 
diff --git a/clang-tools-extra/clangd/test/system-include-extractor.test b/clang-tools-extra/clangd/test/system-include-extractor.test
index 2a2c900316a9161..66882e424bb9216 100644
--- a/clang-tools-extra/clangd/test/system-include-extractor.test
+++ b/clang-tools-extra/clangd/test/system-include-extractor.test
@@ -17,6 +17,7 @@
 # RUN: echo '[ -z "${args##*"-nostdinc"*}" ] || exit' >> %t.dir/bin/my_driver.sh
 # RUN: echo '[ -z "${args##*"--sysroot /my/sysroot/path"*}" ] || exit' >> %t.dir/bin/my_driver.sh
 # RUN: echo '[ -z "${args##*"-isysroot /isysroot"*}" ] || exit' >> %t.dir/bin/my_driver.sh
+# RUN: echo '[ -z "${args##*"-target arm-linux-gnueabihf"*}" ] || exit' >> %t.dir/bin/my_driver.sh
 # RUN: echo 'echo line to ignore >&2' >> %t.dir/bin/my_driver.sh
 # RUN: echo 'printf "Target: arm-linux-gnueabihf\r\n" >&2' >> %t.dir/bin/my_driver.sh
 # RUN: echo 'printf "#include <...> search starts here:\r\n" >&2' >> %t.dir/bin/my_driver.sh
@@ -36,7 +37,7 @@
 
 # Generate a compile_commands.json that will query the mock driver we've
 # created. Which should add a.h and b.h into include search path.
-# RUN: echo '[{"directory": "%/t.dir", "command": "my_driver.sh the-file.cpp -nostdinc --sysroot /my/sysroot/path -isysroot/isysroot", "file": "the-file.cpp"}]' > %t.dir/compile_commands.json
+# RUN: echo '[{"directory": "%/t.dir", "command": "my_driver.sh the-file.cpp --target=arm-linux-gnueabihf -nostdinc --sysroot /my/sysroot/path -isysroot/isysroot", "file": "the-file.cpp"}]' > %t.dir/compile_commands.json
 
 # RUN: sed -e "s|INPUT_DIR|%/t.dir|g" %s > %t.test.1
 # On Windows, we need the URI in didOpen to look like "uri":"file:///C:/..."
@@ -74,7 +75,7 @@
 {"jsonrpc":"2.0","method":"exit"}
 
 # Generate a different compile_commands.json which does not point to the mock driver
-# RUN: echo '[{"directory": "%/t.dir", "command": "gcc the-file.cpp -nostdinc --sysroot /my/sysroot/path -isysroot/isysroot", "file": "the-file.cpp"}]' > %t.dir/compile_commands.json
+# RUN: echo '[{"directory": "%/t.dir", "command": "gcc the-file.cpp --target=arm-linux-gnueabihf -nostdinc --sysroot /my/sysroot/path -isysroot/isysroot", "file": "the-file.cpp"}]' > %t.dir/compile_commands.json
 
 # Generate a clangd config file which points to the mock driver instead
 # RUN: echo 'CompileFlags:' > %t.dir/.clangd