[WebAssembly] Support -stdlib=libc++ switch

Referenced implementation from Fuchsia and Darwin Toolchain.
Still only support CST_Libcxx.  Now checks that the argument
is really '-stdlib=libc++', and display error.

Also, now will pass -lc++ and -lc++abi to the linker.

Patch by Patrick Cheng!

Differential Revision: https://reviews.llvm.org/D41937

llvm-svn: 322382

1 files changed, 36 insertions, 0 deletions

diff --git a/clang/test/Driver/wasm-toolchain.cpp b/clang/test/Driver/wasm-toolchain.cpp
new file mode 100644
index 00000000000..799e0273846
--- /dev/null
+++ b/clang/test/Driver/wasm-toolchain.cpp
@@ -0,0 +1,36 @@
+// A basic clang -cc1 command-line. WebAssembly is somewhat special in
+// enabling -ffunction-sections, -fdata-sections, and -fvisibility=hidden by
+// default.
+
+// RUN: %clang++ %s -### -no-canonical-prefixes -target wasm32-unknown-unknown 2>&1 | FileCheck -check-prefix=CC1 %s
+// CC1: clang{{.*}} "-cc1" "-triple" "wasm32-unknown-unknown" {{.*}} "-fvisibility" "hidden" {{.*}} "-ffunction-sections" "-fdata-sections"
+
+// Ditto, but ensure that a user -fno-function-sections disables the
+// default -ffunction-sections.
+
+// RUN: %clang++ %s -### -target wasm32-unknown-unknown -fno-function-sections 2>&1 | FileCheck -check-prefix=NO_FUNCTION_SECTIONS %s
+// NO_FUNCTION_SECTIONS-NOT: function-sections
+
+// Ditto, but ensure that a user -fno-data-sections disables the
+// default -fdata-sections.
+
+// RUN: %clang++ %s -### -target wasm32-unknown-unknown -fno-data-sections 2>&1 | FileCheck -check-prefix=NO_DATA_SECTIONS %s
+// NO_DATA_SECTIONS-NOT: data-sections
+
+// Ditto, but ensure that a user -fvisibility=default disables the default
+// -fvisibility=hidden.
+
+// RUN: %clang++ %s -### -target wasm32-unknown-unknown -fvisibility=default 2>&1 | FileCheck -check-prefix=FVISIBILITY_DEFAULT %s
+// FVISIBILITY_DEFAULT-NOT: hidden
+
+// A basic C++ link command-line.
+
+// RUN: %clang++ -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo --stdlib=c++ %s 2>&1 | FileCheck -check-prefix=LINK %s
+// LINK: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
+// LINK: lld{{.*}}" "-flavor" "wasm" "-L/foo/lib" "crt1.o" "[[temp]]" "-lc++" "-lc++abi" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
+
+// A basic C++ link command-line with optimization.
+
+// RUN: %clang++ -### -O2 -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s --stdlib=c++ 2>&1 | FileCheck -check-prefix=LINK_OPT %s
+// LINK_OPT: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
+// LINK_OPT: lld{{.*}}" "-flavor" "wasm" "-L/foo/lib" "crt1.o" "[[temp]]" "-lc++" "-lc++abi" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"