[flang-commits] [flang] 7ddbf26 - [flang] Check there's no dependency on C++ libs

[Diana Picus via flang-commits]

Author: Diana Picus
Date: 2021-06-16T08:23:43Z
New Revision: 7ddbf2633911a5c378ad6af01e250f6f252b9032

URL: https://github.com/llvm/llvm-project/commit/7ddbf2633911a5c378ad6af01e250f6f252b9032
DIFF: https://github.com/llvm/llvm-project/commit/7ddbf2633911a5c378ad6af01e250f6f252b9032.diff

LOG: [flang] Check there's no dependency on C++ libs

Add a test to make sure the flang runtime doesn't pull in the C++
runtime libraries.

This is achieved by adding a C file that calls some functions from the
runtime (currently only CpuTime, but we should probably add anything
complicated enough, e.g. IO-related things). We force the C compiler to
use -std=c90 to make sure it's really in C mode (we don't really care
which version of the standard, this one is probably more widely
available). We only enable this test if CMAKE_C_COMPILER is set to
something (which is probably always true in practice).

Differential Revision: https://reviews.llvm.org/D104290

Added: 
    flang/test/Runtime/no-cpp-dep.c

Modified: 
    flang/test/lit.cfg.py
    flang/test/lit.site.cfg.py.in

Removed: 
    


################################################################################
diff  --git a/flang/test/Runtime/no-cpp-dep.c b/flang/test/Runtime/no-cpp-dep.c
new file mode 100644
index 0000000000000..1199f76fbd675
--- /dev/null
+++ b/flang/test/Runtime/no-cpp-dep.c
@@ -0,0 +1,19 @@
+// This test makes sure that flang's runtime does not depend on the C++ runtime
+// library. It tries to link this simple file against libFortranRuntime.a with
+// a C compiler.
+//
+// REQUIRES: c-compiler
+//
+// RUN: %cc -std=c90 %s -I%runtimeincludes %libruntime -o /dev/null
+
+#include "entry-names.h"
+
+// Manually add declarations for the runtime functions that we want to make sure
+// we're testing. We can't include any headers directly since they likely
+// contain C++ code that would explode here.
+double RTNAME(CpuTime)();
+
+int main() {
+  double x = RTNAME(CpuTime)();
+  return x;
+}

diff  --git a/flang/test/lit.cfg.py b/flang/test/lit.cfg.py
index 4109400087e53..cdbb7fc5bf4c6 100644
--- a/flang/test/lit.cfg.py
+++ b/flang/test/lit.cfg.py
@@ -75,6 +75,19 @@
    tools.append(ToolSubst('%flang_fc1', command=FindTool('f18'),
     unresolved='fatal'))
 
+# Define some variables to help us test that the flang runtime doesn't depend on
+# the C++ runtime libraries. For this we need a C compiler. If for some reason
+# we don't have one, we can just disable the test.
+if config.cc:
+    config.available_features.add('c-compiler')
+    tools.append(ToolSubst('%cc', command=config.cc, unresolved='ignore'))
+    tools.append(ToolSubst('%libruntime',
+        command=os.path.join(config.flang_lib_dir, 'libFortranRuntime.a'),
+        unresolved='warn'))
+    tools.append(ToolSubst('%runtimeincludes',
+        command=os.path.join(config.flang_src_dir, 'runtime'),
+        unresolved='warn'))
+
 if config.flang_standalone_build:
     llvm_config.add_tool_substitutions(tools, [config.flang_llvm_tools_dir])
 else:

diff  --git a/flang/test/lit.site.cfg.py.in b/flang/test/lit.site.cfg.py.in
index 17822b0b7d2e4..bcafd8ac43023 100644
--- a/flang/test/lit.site.cfg.py.in
+++ b/flang/test/lit.site.cfg.py.in
@@ -9,8 +9,10 @@ config.flang_src_dir = "@FLANG_SOURCE_DIR@"
 config.flang_tools_dir = "@FLANG_TOOLS_DIR@"
 config.flang_intrinsic_modules_dir = "@FLANG_INTRINSIC_MODULES_DIR@"
 config.flang_llvm_tools_dir = "@CMAKE_BINARY_DIR@/bin"
+config.flang_lib_dir = "@CMAKE_BINARY_DIR@/lib"
 config.python_executable = "@PYTHON_EXECUTABLE@"
 config.flang_standalone_build = @FLANG_STANDALONE_BUILD@
+config.cc = "@CMAKE_C_COMPILER@"
 
 # Control the regression test for flang-new driver
 import lit.util