[Runner] Shuffle some flags around to fix headers search paths order

Author: giordano

src/Runner.jl

@@ -394,7 +394,6 @@ function generate_compiler_wrappers!(platform::AbstractPlatform; bin_path::Abstr
     end
 
     function sanitize_compile_flags!(p::AbstractPlatform, flags::Vector{String})
-        san = sanitize(p)
         if sanitize(p) !== nothing
             if sanitize(p) == "memory"
                 append!(flags, ["-fsanitize=memory"])
@@ -427,41 +426,36 @@ function generate_compiler_wrappers!(platform::AbstractPlatform; bin_path::Abstr
         if lock_microarchitecture
             append!(flags, get_march_flags(arch(p), march(p), "clang"))
         end
+
+        append!(flags, [
+            # We add `-Wno-unused-command-line-argument` so that if someone does something like
+            # `clang -Werror -o foo a.o b.o`, it doesn't complain due to the fact that that is using
+            # `clang` as a linker (and we have no real way to detect that in the wrapper), which
+            # will cause `clang` to complain about compiler flags being passed in.
+            "-Wno-unused-command-line-argument",
+            # We need to override the typical C++ include search paths, because it always includes
+            # the toolchain C++ headers first.  Valentin tracked this down to:
+            # https://github.com/llvm/llvm-project/blob/0378f3a90341d990236c44f297b923a32b35fab1/clang/lib/Driver/ToolChains/Darwin.cpp#L1944-L1978
+            "-nostdinc++",
+            # For systems other than macOS this directory doesn't exist out-of-the-box in our
+            # toolchain, but you can put in there the headers of the C++ standard library for libc++
+            # from LLLVMLibcxx_jll.  This must come before GCC header files (added below).
+            "-isystem /opt/$(aatriplet(p))/$(aatriplet(p))/sys-root/usr/include/c++/v1",
+        ])
+
         if Sys.isapple(p)
             macos_version_flags = clang_use_lld ? (min_macos_version_flags()[1],) : min_macos_version_flags()
             append!(flags, String[
-                # On MacOS, we need to override the typical C++ include search paths, because it always includes
-                # the toolchain C++ headers first.  Valentin tracked this down to:
-                # https://github.com/llvm/llvm-project/blob/0378f3a90341d990236c44f297b923a32b35fab1/clang/lib/Driver/ToolChains/Darwin.cpp#L1944-L1978
-                "-nostdinc++",
-                "-isystem",
-                "/opt/$(aatriplet(p))/$(aatriplet(p))/sys-root/usr/include/c++/v1",
-                # We also add `-Wno-unused-command-line-argument` so that if someone does something like
-                # `clang -Werror -o foo a.o b.o`, it doesn't complain due to the fact that that is using
-                # `clang` as a linker (and we have no real way to detect that in the wrapper), which will
-                # cause `clang` to complain about compiler flags being passed in.
-                "-Wno-unused-command-line-argument",
                 macos_version_flags...,
             ])
         end
+
         sanitize_compile_flags!(p, flags)
         if Sys.isfreebsd(p)
             add_system_includedir(flags)
         end
 
         if !Sys.isbsd(p)
-            # libc++ header files
-            append!(flags, [
-                # NOTE: this first directory doesn't exist out-of-the-box in our toolchain,
-                # but you should put in there the C++ standard libraries for libc++ from
-                # LLLVMLibcxx_jll.  This must come before GCC header files (added below).
-                "-isystem /opt/$(aatriplet(p))/$(aatriplet(p))/sys-root/include/c++/v1",
-                # This directory contains C header files.  Must come after the C++ ones, see
-                # for example <https://github.com/llvm/llvm-project/blob/4bcdb26dac4cdadd7f8850a5f9b2e775b73aaf7f/libcxx/include/cmath#L336-L338>.
-                # This directory is in default search paths, but we have to explicitly put
-                # it here to give it higher precedence than the following directories.
-                "-isystem /opt/$(aatriplet(p))/$(aatriplet(p))/sys-root/usr/include",
-            ])
             # GCC header files
             if !isnothing(gcc_version)
                 append!(flags, [

test/runners.jl

@@ -197,7 +197,9 @@ end
     end
 
     # This tests only that compilers for all platforms can build and link simple C++ code
-    @testset "Compilation - $(platform) - $(compiler)" for platform in platforms, compiler in ("c++", "g++", "clang++")
+    # Note: we test the slightly weird `clang -x c++` as compiler driver because that's used
+    # in some cases and we want to make sure it works correctly.
+    @testset "Compilation - $(platform) - $(compiler)" for platform in platforms, (compiler, linker) in (("c++", "c++"), ("g++", "g++"), ("clang -x c++", "clang++"))
         mktempdir() do dir
             ur = preferred_runner()(dir; platform=platform)
             iobuff = IOBuffer()
@@ -221,13 +223,15 @@ end
                 echo '$(test_cpp)' > test.cpp
                 echo '$(main_cpp)' > main.cpp
                 # Build object file
-                $(compiler) -Werror -std=c++11 -c test.cpp -o test.o
-                # Build shared library
-                $(compiler) -Werror -std=c++11 $(needfpic) -shared test.cpp -o libtest.\${dlext}
+                $(compiler) $(needfpic) -Werror -std=c++11 -c test.cpp -o test.o
+                # Link shared library
+                $(linker) -shared test.o -o libtest.\${dlext}
                 # Build and link program with object file
-                $(compiler) -Werror -std=c++11 -o main main.cpp test.o
-                # Build and link program with shared library
-                $(compiler) -Werror -std=c++11 -o main main.cpp -L. -ltest
+                $(compiler) $(needfpic) -Werror -std=c++11 -c main.cpp -o main.o
+                # Link main program with test object file
+                $(linker) -o main main.o test.o
+                # Link main program with shared library
+                $(linker) -o main main.o -L. -ltest
                 """
             cmd = `/bin/bash -c "$(test_script)"`
             @test run(ur, cmd, iobuff; tee_stream=devnull)