[Driver] Make -print-libgcc-file-name print compiler-rt lib when used

Make the -print-libgcc-file-name option print an appropriate compiler
runtime library, that is libgcc.a if gcc runtime is used
and an appropriate compiler-rt library if that runtime is used.

The main use for this is to allow linking executables built with
-nodefaultlibs (e.g. to avoid linking to the standard C++ library) to
the compiler runtime library, e.g. using:

  clang++ ... -nodefaultlibs $(clang++ ... -print-libgcc-file-name)

in which case currently a program built like this linked to the gcc
runtime unconditionally. The patch fixes it to use compiler-rt libraries
instead when compiler-rt is the active runtime.

Differential Revision: https://reviews.llvm.org/D25338

llvm-svn: 283746

4 files changed, 24 insertions, 1 deletions

diff --git a/clang/test/Driver/montavista-gcc-toolchain.c b/clang/test/Driver/montavista-gcc-toolchain.c
index da76e957943..402e53b63c5 100644
--- a/clang/test/Driver/montavista-gcc-toolchain.c
+++ b/clang/test/Driver/montavista-gcc-toolchain.c
@@ -1,6 +1,6 @@
 // Test that the montavista gcc-toolchain is correctly detected
 //
-// RUN: %clang -print-libgcc-file-name 2>&1 \
+// RUN: %clang -rtlib=platform -print-libgcc-file-name 2>&1 \
 // RUN:     --target=i686-montavista-linux \
 // RUN:     --gcc-toolchain=%S/Inputs/montavista_i686_tree/usr \
 // RUN:   | FileCheck %s
diff --git a/clang/test/Driver/print-libgcc-file-name-clangrt.c b/clang/test/Driver/print-libgcc-file-name-clangrt.c
new file mode 100644
index 00000000000..9f8120c31d9
--- /dev/null
+++ b/clang/test/Driver/print-libgcc-file-name-clangrt.c
@@ -0,0 +1,11 @@
+// Test that -print-libgcc-file-name correctly respects -rtlib=compiler-rt.
+
+// RUN: %clang -rtlib=compiler-rt -print-libgcc-file-name 2>&1 \
+// RUN:     --target=x86_64-pc-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-CLANGRT-X8664 %s
+// CHECK-CLANGRT-X8664: libclang_rt.builtins-x86_64.a
+
+// RUN: %clang -rtlib=compiler-rt -print-libgcc-file-name 2>&1 \
+// RUN:     --target=i686-pc-linux \
+// RUN:   | FileCheck --check-prefix=CHECK-CLANGRT-I686 %s
+// CHECK-CLANGRT-I686: libclang_rt.builtins-i686.a
diff --git a/clang/test/Driver/print-libgcc-file-name-libgcc.c b/clang/test/Driver/print-libgcc-file-name-libgcc.c
new file mode 100644
index 00000000000..3ca8fb900e3
--- /dev/null
+++ b/clang/test/Driver/print-libgcc-file-name-libgcc.c
@@ -0,0 +1,7 @@
+// Test that -print-libgcc-file-name correctly respects -rtlib=libgcc.
+
+// REQUIRES: libgcc
+
+// RUN: %clang -rtlib=libgcc -print-libgcc-file-name 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-LIBGCC %s
+// CHECK-LIBGCC: libgcc.a
diff --git a/clang/test/lit.cfg b/clang/test/lit.cfg
index ad4cf834f91..aea4d6aa316 100644
--- a/clang/test/lit.cfg
+++ b/clang/test/lit.cfg
@@ -375,6 +375,11 @@ if platform.system() not in ['Windows']:
 if platform.system() not in ['Windows']:
     config.available_features.add('utf8-capable-terminal')
 
+# Support for libgcc runtime. Used to rule out tests that require
+# clang to run with -rtlib=libgcc.
+if platform.system() not in ['Darwin', 'Fuchsia']:
+    config.available_features.add('libgcc')
+
 # Native compilation: Check if triples match.
 # FIXME: Consider cases that target can be executed
 # even if host_triple were different from target_triple.