Fix a bug that -isysroot is completely ignored on Unix

[yamaguchi]

Summary

-isysroot is the flag which set the system root directory.
This bug report [1] shows that -isysroot is not handled at all on Unix, so fixed this bug.

After this diff, I could get this result [2].

[1] https://bugs.llvm.org//show_bug.cgi?id=11503
[2] https://pastebin.com/TeCmn9mj

[ruiu]

Testcase?

[v.g.vassilev]

@yamaguchi, could you add a testcase? (cd clang_src_folder; git grep isysroot test) would give you an idea how and where to write that test.

[yamaguchi]

Before the change in D31495, I couldn't pass the test and get this result [1]

However after the change in D31495, I could pass the test and get result below.

`--> build/bin/llvm-lit ~/llvm/tools/clang/test/Driver/sysroot-flags.c
llvm-lit: /home/yamaguchi/llvm/tools/clang/test/lit.cfg:200: note: using clang: '/home/yamaguchi/build/./bin/clang'
-- Testing: 1 tests, 1 threads --
PASS: Clang :: Driver/sysroot-flags.c (1 of 1)
Testing Time: 0.06s
  Expected Passes    : 1

So I thought this testcase is correct because -isysroot doesn't pass the test when it is not handled at all, but will pass the test when it is.
I would like to ask for advice.

[1] https://pastebin.com/QPumpsVU

[v.g.vassilev]

@yamaguchi Please add the testcase to this patch.

[yamaguchi]

I thought this testcase is already exists and working in clang/test/Driver/sysroot-flags.c, but is it not?

sysroot-flags.c

1 // Check for proper handling of --sysroot and -isysroot flags.
2 
3 // RUN: %clang -### -fsyntax-only -isysroot /foo/bar %s 2>&1 | \
4 // RUN:   FileCheck %s -check-prefix=ISYSROOT
5 // ISYSROOT: "-isysroot" "{{[^"]*}}/foo/bar"

[yamaguchi]

Add path to the file.

[yamaguchi]

Add testcase.

[v.g.vassilev]

LGTM.

lib/Frontend/CompilerInvocation.cpp

     Opts.AddPath(A->getValue(), frontend::ObjCXXSystem, false, true);
 
   // Add the internal paths from a driver that detects standard include paths.
   for (const Arg *A :
        Args.filtered(OPT_internal_isystem, OPT_internal_externc_isystem)) {
     frontend::IncludeDirGroup Group = frontend::System;
     if (A->getOption().matches(OPT_internal_externc_isystem))
       Group = frontend::ExternCSystem;
-    Opts.AddPath(A->getValue(), Group, false, true);
+    Opts.AddPath(A->getValue(), Group, false, false);
   }
 
   // Add the path prefixes which are implicitly treated as being system headers.
   for (const Arg *A :
        Args.filtered(OPT_system_header_prefix, OPT_no_system_header_prefix))
     Opts.AddSystemHeaderPrefix(
         A->getValue(), A->getOption().matches(OPT_system_header_prefix));
 

test/Driver/sysroot-flags.c

 // ISYSROOT_AND_SYSROOT: "--sysroot{{" "|=}}{{[^"]*}}/foo/bar"
 
 // Check that omitting the equals works as well.
 // RUN: %clang -### -target x86_64-unknown-linux-gnu \
 // RUN:   --sysroot /foo/bar -o /dev/null %s 2>&1 | \
 // RUN:   FileCheck %s -check-prefix=SYSROOT_SEPARATE
 // SYSROOT_SEPARATE: "-isysroot" "{{[^"]*}}/foo/bar"
 // SYSROOT_SEPARATE: "--sysroot{{" "|=}}{{[^"]*}}/foo/bar"
+
+// Check that -isysroot is handled properly
+// RUN: %clang -isysroot /foo/bar -c %s -v 2>&1 | \
+// RUN:   grep "/foo/bar"