[clang] [hexagon] Add resource include dir

[bcain]

This patch is so far just for discussion, still needs tests, etc. The motivation for this patch is to be able to include the intrinsic header files installed in the resource dir.

I've taken inspiration from ToolChains/Linux.cpp here.

[MaskRay]

Thanks for the patch. This makes the behavior closer to Linux.cpp . Request changes to clear my queue before a test is added...

clang/lib/Driver/ToolChains/Hexagon.cpp

604

To match Linux.cpp, this code block should be unconditional.

[bcain]

clang/lib/Driver/ToolChains/Hexagon.cpp

604

I *think* this is an intentional difference from Linux.cpp in order to suit hexagon-unknown-elf. @sidneym do you think we need this conditional behavior?

[sidneym]

clang/lib/Driver/ToolChains/Hexagon.cpp

604

The isMusl check is to distinguish between our internal c-library and musl c-library.

[bcain]

Add a test case, address failing test.

[MaskRay]

Thanks for the test. linux-cross.cpp has some -SAME: {{^}} and "[[RESOURCE]]/include" patterns which you may use

[bcain]

Test case updates per suggestion.

[MaskRay]

clang/test/Driver/hexagon-toolchain-linux.c

106

If you don't specify -resource-dir=%S/Inputs/resource_dir, under certain CMake configurations, the -resource-dir may be unreliable.

117

Some / may need to be \.

The Windows premerge test may give you a failure.
(That's why I just add UNSUPPORTED: system-windows to not deal with the backslash madness.)

[bcain]

Suggestions from Fangrui: override the resource-dir with an explicit arg, disable for windows.

clang/lib/Driver/ToolChains/Hexagon.cpp

void HexagonToolChain::addClangTargetOptions(const ArgList &DriverArgs,
   if (isAutoHVXEnabled(DriverArgs)) {
     CC1Args.push_back("-mllvm");
     CC1Args.push_back("-hexagon-autohvx");
   }
 }
 
 void HexagonToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                                  ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
-      DriverArgs.hasArg(options::OPT_nostdlibinc))
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
     return;
 
+  const bool IsELF = !getTriple().isMusl() && !getTriple().isOSLinux();
+  const bool IsLinuxMusl = getTriple().isMusl() && getTriple().isOSLinux();
+
   const Driver &D = getDriver();
-  if (!D.SysRoot.empty()) {
+  SmallString<128> ResourceDirInclude(D.ResourceDir);
+  if (!IsELF) {
+    llvm::sys::path::append(ResourceDirInclude, "include");
+    if (!DriverArgs.hasArg(options::OPT_nobuiltininc) &&
+        (!IsLinuxMusl || DriverArgs.hasArg(options::OPT_nostdlibinc)))
+      addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
+  }
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+  const bool HasSysRoot = !D.SysRoot.empty();
+  if (HasSysRoot) {
     SmallString<128> P(D.SysRoot);
-    if (getTriple().isMusl())
+    if (IsLinuxMusl)
       llvm::sys::path::append(P, "usr/include");
     else
       llvm::sys::path::append(P, "include");
+
     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
-    return;
+    // LOCAL_INCLUDE_DIR
+    addSystemInclude(DriverArgs, CC1Args, P + "/usr/local/include");
+    // TOOL_INCLUDE_DIR
+    AddMultilibIncludeArgs(DriverArgs, CC1Args);
   }
 
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && IsLinuxMusl)
+    addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
+
+  if (HasSysRoot)
+    return;
   std::string TargetDir = getHexagonTargetDir(D.getInstalledDir(),
                                               D.PrefixDirs);
   addExternCSystemInclude(DriverArgs, CC1Args, TargetDir + "/hexagon/include");
 }
 
 void HexagonToolChain::addLibCxxIncludePaths(
     const llvm::opt::ArgList &DriverArgs,
     llvm::opt::ArgStringList &CC1Args) const {

clang/test/Driver/hexagon-toolchain-linux.c

 // -----------------------------------------------------------------------------
 // RUN: %clangxx -### -target hexagon-unknown-elf \
 // RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
 // RUN:   -stdlib=libc++ \
 // RUN:   -mcpu=hexagonv60 \
 // RUN:   %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK007 %s
 // CHECK007:          "-internal-isystem" "{{.*}}hexagon{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}v1"
+// -----------------------------------------------------------------------------
+// internal-isystem for linux with and without musl
+// -----------------------------------------------------------------------------
+// RUN: %clangxx -### -target hexagon-unknown-linux-musl \
+// RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
+// RUN:   %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK008 %s
+// RUN: %clangxx -### -target hexagon-unknown-linux \
+// RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
+// RUN:   %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK008 %s
+// CHECK008:  "-internal-isystem" "{{.*}}clang{{/|\\\\}}{{.*}}{{/|\\\\}}include"