[Driver] Linux.cpp: add -internal-isystem lib/../$triple/include

With this change, for `#include <ar.h>`, `clang --target=aarch64-linux-gnu`
will read `/usr/lib/gcc/aarch64-linux-gnu/10/../../../../aarch64-linux-gnu/include/ar.h`
(on Debian gcc->gcc-cross)
instead of `/usr/include/ar.h`. Some glibc headers (e.g. gnu/stubs.h) are different across architectures.

diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 0785796..b5efa58 100644 (file)
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -2867,13 +2867,19 @@ void Generic_GCC::AddMultiarchPaths(const Driver &D,
 void Generic_GCC::AddMultilibIncludeArgs(const ArgList &DriverArgs,
                                          ArgStringList &CC1Args) const {
   // Add include directories specific to the selected multilib set and multilib.
-  if (GCCInstallation.isValid()) {
-    const auto &Callback = Multilibs.includeDirsCallback();
-    if (Callback) {
-      for (const auto &Path : Callback(GCCInstallation.getMultilib()))
-        addExternCSystemIncludeIfExists(
-            DriverArgs, CC1Args, GCCInstallation.getInstallPath() + Path);
-    }
+  if (!GCCInstallation.isValid())
+    return;
+  // gcc TOOL_INCLUDE_DIR.
+  const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
+  std::string LibPath(GCCInstallation.getParentLibPath());
+  addSystemInclude(DriverArgs, CC1Args,
+                   Twine(LibPath) + "/../" + GCCTriple.str() + "/include");
+
+  const auto &Callback = Multilibs.includeDirsCallback();
+  if (Callback) {
+    for (const auto &Path : Callback(GCCInstallation.getMultilib()))
+      addExternCSystemIncludeIfExists(DriverArgs, CC1Args,
+                                      GCCInstallation.getInstallPath() + Path);
   }
 }
 

diff --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
index 6599f46..0e8da0f 100644 (file)
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -574,9 +574,14 @@ void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
     return;
 
-  if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
+  if (!DriverArgs.hasArg(options::OPT_nostdlibinc)) {
+    // LOCAL_INCLUDE_DIR
     addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
+    // TOOL_INCLUDE_DIR
+    AddMultilibIncludeArgs(DriverArgs, CC1Args);
+  }
 
+  // Note: in gcc, GCC_INCLUDE_DIR (private headers) precedes LOCAL_INCLUDE_DIR.
   SmallString<128> ResourceDirInclude(D.ResourceDir);
   llvm::sys::path::append(ResourceDirInclude, "include");
   if (!DriverArgs.hasArg(options::OPT_nobuiltininc) &&
@@ -599,11 +604,6 @@ void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
     return;
   }
 
-  // Lacking those, try to detect the correct set of system includes for the
-  // target triple.
-
-  AddMultilibIncludeArgs(DriverArgs, CC1Args);
-
   // Implement generic Debian multiarch support.
   const StringRef X86_64MultiarchIncludeDirs[] = {
       "/usr/include/x86_64-linux-gnu",

diff --git a/clang/test/Driver/linux-header-search.cpp b/clang/test/Driver/linux-header-search.cpp
index 4aed02f..3560bd0 100644 (file)
--- a/clang/test/Driver/linux-header-search.cpp
+++ b/clang/test/Driver/linux-header-search.cpp
@@ -188,7 +188,8 @@
 // CHECK-DEBIAN-X86: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/i686-linux-gnu/4.5/../../../../include/c++/4.5/i686-linux-gnu"
 // CHECK-DEBIAN-X86: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/i686-linux-gnu/4.5/../../../../include/c++/4.5/backward"
 // CHECK-DEBIAN-X86: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
-// CHECK-DEBIAN-X86: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+// CHECK-DEBIAN-X86-SAME: {{^}} "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/i686-linux-gnu/4.5/../../../../i686-linux-gnu/include"
+// CHECK-DEBIAN-X86-SAME: {{^}} "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
 // CHECK-DEBIAN-X86: "-internal-externc-isystem" "[[SYSROOT]]/usr/include/i386-linux-gnu"
 // CHECK-DEBIAN-X86: "-internal-externc-isystem" "[[SYSROOT]]/include"
 // CHECK-DEBIAN-X86: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
@@ -204,7 +205,8 @@
 // CHECK-DEBIAN-X86-64: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnu/4.5/../../../../include/c++/4.5/x86_64-linux-gnu"
 // CHECK-DEBIAN-X86-64: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnu/4.5/../../../../include/c++/4.5/backward"
 // CHECK-DEBIAN-X86-64: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
-// CHECK-DEBIAN-X86-64: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+// CHECK-DEBIAN-X86-64-SAME: {{^}} "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-linux-gnu/4.5/../../../../x86_64-linux-gnu/include"
+// CHECK-DEBIAN-X86-64-SAME: {{^}} "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
 // CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/usr/include/x86_64-linux-gnu"
 // CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/include"
 // CHECK-DEBIAN-X86-64: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"