[Flang] Rename libFortranRuntime.a to libflang_rt.runtime.a (#122341)

Following the conclusion of the
[RFC](https://discourse.llvm.org/t/rfc-names-for-flang-rt-libraries/84321),
rename Flang's runtime libraries as follows:

 * libFortranRuntime.(a|so) to libflang_rt.runtime.(a|so)
 * libFortranFloat128Math.a to libflang_rt.quadmath.a
* libCufRuntime_cuda_${CUDAToolkit_VERSION_MAJOR}.(a|so) to
libflang_rt.cuda_${CUDAToolkit_VERSION_MAJOR}.(a|so)

This follows the same naming scheme as Compiler-RT libraries
(`libclang_rt.${component}.(a|so)`). It provides some consistency
between Flang's runtime libraries for current and potential future
library components.

Author: Meinersbur

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -1321,7 +1321,7 @@ void tools::addOpenMPHostOffloadingArgs(const Compilation &C,
 /// Add Fortran runtime libs
 void tools::addFortranRuntimeLibs(const ToolChain &TC, const ArgList &Args,
                                   llvm::opt::ArgStringList &CmdArgs) {
-  // Link FortranRuntime
+  // Link flang_rt.runtime
   // These are handled earlier on Windows by telling the frontend driver to
   // add the correct libraries to link against as dependents in the object
   // file.
@@ -1330,14 +1330,14 @@ void tools::addFortranRuntimeLibs(const ToolChain &TC, const ArgList &Args,
     F128LibName.consume_front_insensitive("lib");
     if (!F128LibName.empty()) {
       bool AsNeeded = !TC.getTriple().isOSAIX();
-      CmdArgs.push_back("-lFortranFloat128Math");
+      CmdArgs.push_back("-lflang_rt.quadmath");
       if (AsNeeded)
         addAsNeededOption(TC, Args, CmdArgs, /*as_needed=*/true);
       CmdArgs.push_back(Args.MakeArgString("-l" + F128LibName));
       if (AsNeeded)
         addAsNeededOption(TC, Args, CmdArgs, /*as_needed=*/false);
     }
-    CmdArgs.push_back("-lFortranRuntime");
+    CmdArgs.push_back("-lflang_rt.runtime");
     addArchSpecificRPath(TC, Args, CmdArgs);
 
     // needs libexecinfo for backtrace functions

clang/lib/Driver/ToolChains/Flang.cpp

@@ -346,11 +346,15 @@ static void processVSRuntimeLibrary(const ToolChain &TC, const ArgList &Args,
                                     ArgStringList &CmdArgs) {
   assert(TC.getTriple().isKnownWindowsMSVCEnvironment() &&
          "can only add VS runtime library on Windows!");
-  // if -fno-fortran-main has been passed, skip linking Fortran_main.a
-  if (TC.getTriple().isKnownWindowsMSVCEnvironment()) {
-    CmdArgs.push_back(Args.MakeArgString(
-        "--dependent-lib=" + TC.getCompilerRTBasename(Args, "builtins")));
-  }
+
+  // Flang/Clang (including clang-cl) -compiled programs targeting the MSVC ABI
+  // should only depend on msv(u)crt. LLVM still emits libgcc/compiler-rt
+  // functions in some cases like 128-bit integer math (__udivti3, __modti3,
+  // __fixsfti, __floattidf, ...) that msvc does not support. We are injecting a
+  // dependency to Compiler-RT's builtin library where these are implemented.
+  CmdArgs.push_back(Args.MakeArgString(
+      "--dependent-lib=" + TC.getCompilerRTBasename(Args, "builtins")));
+
   unsigned RTOptionID = options::OPT__SLASH_MT;
   if (auto *rtl = Args.getLastArg(options::OPT_fms_runtime_lib_EQ)) {
     RTOptionID = llvm::StringSwitch<unsigned>(rtl->getValue())
@@ -364,26 +368,26 @@ static void processVSRuntimeLibrary(const ToolChain &TC, const ArgList &Args,
   case options::OPT__SLASH_MT:
     CmdArgs.push_back("-D_MT");
     CmdArgs.push_back("--dependent-lib=libcmt");
-    CmdArgs.push_back("--dependent-lib=FortranRuntime.static.lib");
+    CmdArgs.push_back("--dependent-lib=flang_rt.runtime.static.lib");
     break;
   case options::OPT__SLASH_MTd:
     CmdArgs.push_back("-D_MT");
     CmdArgs.push_back("-D_DEBUG");
     CmdArgs.push_back("--dependent-lib=libcmtd");
-    CmdArgs.push_back("--dependent-lib=FortranRuntime.static_dbg.lib");
+    CmdArgs.push_back("--dependent-lib=flang_rt.runtime.static_dbg.lib");
     break;
   case options::OPT__SLASH_MD:
     CmdArgs.push_back("-D_MT");
     CmdArgs.push_back("-D_DLL");
     CmdArgs.push_back("--dependent-lib=msvcrt");
-    CmdArgs.push_back("--dependent-lib=FortranRuntime.dynamic.lib");
+    CmdArgs.push_back("--dependent-lib=flang_rt.runtime.dynamic.lib");
     break;
   case options::OPT__SLASH_MDd:
     CmdArgs.push_back("-D_MT");
     CmdArgs.push_back("-D_DEBUG");
     CmdArgs.push_back("-D_DLL");
     CmdArgs.push_back("--dependent-lib=msvcrtd");
-    CmdArgs.push_back("--dependent-lib=FortranRuntime.dynamic_dbg.lib");
+    CmdArgs.push_back("--dependent-lib=flang_rt.runtime.dynamic_dbg.lib");
     break;
   }
 }

flang/CMakeLists.txt

@@ -301,7 +301,7 @@ set(FLANG_DEFAULT_LINKER "" CACHE STRING
   "Default linker to use (linker name or absolute path, empty for platform default)")
 
 set(FLANG_DEFAULT_RTLIB "" CACHE STRING
-   "Default Fortran runtime library to use (\"libFortranRuntime\"), leave empty for platform default.")
+   "Default Fortran runtime library to use (\"libflang_rt.runtime\"), leave empty for platform default.")
 
 if (NOT(FLANG_DEFAULT_RTLIB STREQUAL ""))
   message(WARNING "Resetting Flang's default runtime library to use platform default.")

flang/cmake/modules/AddFlang.cmake

@@ -57,7 +57,7 @@ function(add_flang_library name)
     set(LIBTYPE SHARED)
   elseif(ARG_STATIC)
     # If BUILD_SHARED_LIBS and ARG_STATIC are both set, llvm_add_library prioritizes STATIC.
-    # This is required behavior for libFortranFloat128Math.
+    # This is required behavior for libflang_rt.quadmath.
     set(LIBTYPE STATIC)
   else()
     # Let llvm_add_library decide, taking BUILD_SHARED_LIBS into account.

flang/docs/FlangDriver.md

@@ -175,18 +175,18 @@ like this:
 
 ```
 $ flang -v -o example example.o
-"/usr/bin/ld" [...] example.o [...] "-lFortranRuntime" [...]
+"/usr/bin/ld" [...] example.o [...] "-lflang_rt.runtime" [...]
 ```
 
 The automatically added libraries are:
 
-* `FortranRuntime`: Provides most of the Flang runtime library.
+* `flang_rt.runtime`: Provides most of the Flang runtime library.
 
 If the code is C/C++ based and invokes Fortran routines, one can either use Clang
 or Flang as the linker driver.  If Clang is used, it will automatically all
 required runtime libraries needed by C++ (e.g., for STL) to the linker invocation.
 In this case, one has to explicitly provide the Fortran runtime library
-`FortranRuntime`.  An alternative is to use Flang to link.
+`flang_rt.runtime`.  An alternative is to use Flang to link.
 In this case, it may be required to explicitly supply C++ runtime libraries.
 
 On Darwin, the logical root where the system libraries are located (sysroot)

flang/docs/GettingStarted.md

@@ -216,7 +216,7 @@ cmake \
   -DCMAKE_CUDA_COMPILER=clang \
   -DCMAKE_CUDA_HOST_COMPILER=clang++ \
   ../runtime/
-make -j FortranRuntime
+make -j flang-rt
 ```
 
 Note that the used version of `clang` must [support](https://releases.llvm.org/16.0.0/tools/clang/docs/ReleaseNotes.html#cuda-support)
@@ -239,7 +239,7 @@ cmake \
   -DCMAKE_CUDA_HOST_COMPILER=clang++ \
   ../runtime/
 
-make -j FortranRuntime
+make -j flang-rt
 ```
 
 Note that `nvcc` might limit support to certain
@@ -294,7 +294,7 @@ cmake \
   -DFLANG_OMP_DEVICE_ARCHITECTURES="all" \
   ../runtime/
 
-make -j FortranRuntime
+make -j flang-rt
 ```
 
 The result of the build is a "device-only" library, i.e. the host
@@ -309,7 +309,7 @@ The same set of CMake variables works for Flang in-tree build.
 One may provide optional CMake variables to customize the build. Available options:
 
 * `-DFLANG_RUNTIME_F128_MATH_LIB=libquadmath`: enables build of
-  `FortranFloat128Math` library that provides `REAL(16)` math APIs
+  `flang_rt.quadmath` library that provides `REAL(16)` math APIs
   for intrinsics such as `SIN`, `COS`, etc. GCC `libquadmath`'s header file
   `quadmath.h` must be available to the build compiler.
   [More details](Real16MathSupport.md).

flang/docs/OpenACC-descriptor-management.md

@@ -427,7 +427,7 @@ The implementation's behavior may be described as (OpenACC 2.7.2):
 
 All the "is-present" checks and the data actions for the auxiliary pointers must be performed atomically with regards to the present counters bookkeeping.
 
-The API relies on the primitives provided by `liboffload`, so it is provided by a new F18 runtime library, e.g. `FortranOffloadRuntime`, that depends on `FortranRuntime` and `liboffload`.  The F18 driver adds `FortranOffloadRuntime` for linking under `-fopenacc`/`-fopenmp` (and maybe additional switches like `-fopenmp-targets`).
+The API relies on the primitives provided by `liboffload`, so it is provided by a new F18 runtime library, e.g. `FortranOffloadRuntime`, that depends on `flang_rt.runtime` and `liboffload`.  The F18 driver adds `FortranOffloadRuntime` for linking under `-fopenacc`/`-fopenmp` (and maybe additional switches like `-fopenmp-targets`).
 
 ## TODOs:
 

flang/docs/Real16MathSupport.md

@@ -12,9 +12,9 @@ To support most `REAL(16)` (i.e. 128-bit float) math intrinsics Flang relies
 on third-party libraries providing the implementation.
 
 `-DFLANG_RUNTIME_F128_MATH_LIB=libquadmath` CMake option can be used
-to build `FortranFloat128Math` library that has unresolved references
+to build `libflang_rt.quadmath` library that has unresolved references
 to GCC `libquadmath` library. A Flang driver built with this option
-will automatically link `FortranFloat128Math` and `libquadmath` libraries
+will automatically link `libflang_rt.quadmath` and `libquadmath` libraries
 to any Fortran program. This implies that `libquadmath` library
 has to be available in the standard library paths, so that linker
 can find it. The `libquadmath` library installation into Flang project

flang/docs/ReleaseNotes.md

@@ -36,6 +36,13 @@ page](https://llvm.org/releases/).
 
 ## Build System Changes
 
+ * The FortranRuntime library has been renamed to `flang_rt.runtime`.
+
+ * The FortranFloat128Math library has been renamed to `flang_rt.quadmath`.
+
+ * The CufRuntime_cuda_${version} library has been renamed to
+   `flang_rt.cuda_${version}`.
+
 ## New Issues Found
 
 

flang/examples/ExternalHelloWorld/CMakeLists.txt

@@ -5,5 +5,5 @@ add_llvm_example(external-hello-world
 
 target_link_libraries(external-hello-world
   PRIVATE
-  FortranRuntime
+  flang_rt.runtime
   )

flang/lib/Optimizer/Builder/IntrinsicCall.cpp

@@ -809,8 +809,8 @@ prettyPrintIntrinsicName(fir::FirOpBuilder &builder, mlir::Location loc,
 // Generate a call to the Fortran runtime library providing
 // support for 128-bit float math.
 // On 'HAS_LDBL128' targets the implementation
-// is provided by FortranRuntime, otherwise, it is done via
-// FortranFloat128Math library. In the latter case the compiler
+// is provided by flang_rt, otherwise, it is done via the
+// libflang_rt.quadmath library. In the latter case the compiler
 // has to be built with FLANG_RUNTIME_F128_MATH_LIB to guarantee
 // proper linking actions in the driver.
 static mlir::Value genLibF128Call(fir::FirOpBuilder &builder,

flang/runtime/CMakeLists.txt

@@ -241,13 +241,13 @@ set(supported_files
   utf.cpp
   )
 
-enable_cuda_compilation(FortranRuntime "${supported_files}")
+enable_cuda_compilation(flang_rt "${supported_files}")
 enable_omp_offload_compilation("${supported_files}")
 
-if (NOT TARGET FortranFloat128Math)
-  # If FortranFloat128Math is not defined, then we are not building
-  # standalone FortranFloat128Math library. Instead, include
-  # the relevant sources into FortranRuntime itself.
+if (NOT TARGET flang_rt.quadmath)
+  # If flang_rt.quadmath is not defined, then we are not building
+  # standalone flang_rt.quadmath library. Instead, include
+  # the relevant sources into flang_rt.runtime itself.
   # The information is provided via FortranFloat128MathILib
   # interface library.
   get_target_property(f128_sources
@@ -275,51 +275,66 @@ if (NOT TARGET FortranFloat128Math)
 endif()
 
 if (NOT DEFINED MSVC)
-  add_flang_library(FortranRuntime
+  add_flang_library(flang_rt.runtime
     ${sources}
     LINK_LIBS
     ${linked_libraries}
 
     INSTALL_WITH_TOOLCHAIN
   )
 else()
-  add_flang_library(FortranRuntime
+  add_flang_library(flang_rt.runtime
     ${sources}
     LINK_LIBS
     ${linked_libraries}
   )
   set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreaded)
-  add_flang_library(FortranRuntime.static ${sources}
+  add_flang_library(flang_rt.runtime.static ${sources}
     INSTALL_WITH_TOOLCHAIN)
-  set_target_properties(FortranRuntime.static PROPERTIES FOLDER "Flang/Runtime Libraries")
+  set_target_properties(flang_rt.runtime.static PROPERTIES FOLDER "Flang/Runtime Libraries")
   set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreadedDLL)
-  add_flang_library(FortranRuntime.dynamic ${sources}
+  add_flang_library(flang_rt.runtime.dynamic ${sources}
     INSTALL_WITH_TOOLCHAIN)
-  set_target_properties(FortranRuntime.dynamic PROPERTIES FOLDER "Flang/Runtime Libraries")
+  set_target_properties(flang_rt.runtime.dynamic PROPERTIES FOLDER "Flang/Runtime Libraries")
   set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreadedDebug)
-  add_flang_library(FortranRuntime.static_dbg ${sources}
+  add_flang_library(flang_rt.runtime.static_dbg ${sources}
     INSTALL_WITH_TOOLCHAIN)
-  set_target_properties(FortranRuntime.static_dbg PROPERTIES FOLDER "Flang/Runtime Libraries")
+  set_target_properties(flang_rt.runtime.static_dbg PROPERTIES FOLDER "Flang/Runtime Libraries")
   set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreadedDebugDLL)
-  add_flang_library(FortranRuntime.dynamic_dbg ${sources}
+  add_flang_library(flang_rt.runtime.dynamic_dbg ${sources}
     INSTALL_WITH_TOOLCHAIN)
-  set_target_properties(FortranRuntime.dynamic_dbg PROPERTIES FOLDER "Flang/Runtime Libraries")
-  add_dependencies(FortranRuntime FortranRuntime.static FortranRuntime.dynamic
-    FortranRuntime.static_dbg FortranRuntime.dynamic_dbg)
+  set_target_properties(flang_rt.runtime.dynamic_dbg PROPERTIES FOLDER "Flang/Runtime Libraries")
+  add_dependencies(flang_rt.runtime
+    flang_rt.runtime.static
+    flang_rt.runtime.dynamic
+    flang_rt.runtime.static_dbg
+    flang_rt.runtime.dynamic_dbg)
 endif()
-set_target_properties(FortranRuntime PROPERTIES FOLDER "Flang/Runtime Libraries")
+set_target_properties(flang_rt.runtime PROPERTIES FOLDER "Flang/Runtime Libraries")
 
-# If FortranRuntime is part of a Flang build (and not a separate build) then
+# If flang_rt is part of a Flang build (and not a separate build) then
 # add dependency to make sure that Fortran runtime library is being built after
 # we have the Flang compiler available.  This also includes the MODULE files
 # that compile when the 'flang' target is built.
 #
 # TODO: This is a workaround and should be updated when runtime build procedure
 # is changed to a regular runtime build.  See discussion in PR #95388.
 if (TARGET flang AND TARGET module_files)
-  add_dependencies(FortranRuntime flang module_files)
+  add_dependencies(flang_rt.runtime flang module_files)
 endif()
 
 if (FLANG_CUF_RUNTIME)
   add_subdirectory(CUDA)
 endif()
+
+# Compatibility targets.
+add_custom_target(flang-rt)
+add_dependencies(flang-rt flang_rt.runtime)
+if (TARGET flang_rt.quadmath)
+  add_dependencies(flang-rt flang_rt.quadmath)
+endif ()
+if (TARGET flang_rt.cuda_${CUDAToolkit_VERSION_MAJOR})
+  add_dependencies(flang-rt flang_rt.cuda_${CUDAToolkit_VERSION_MAJOR})
+endif ()
+add_custom_target(FortranRuntime)
+add_dependencies(FortranRuntime flang_rt.runtime)

flang/runtime/CUDA/CMakeLists.txt

@@ -8,10 +8,10 @@
 
 include_directories(${CUDAToolkit_INCLUDE_DIRS})
 
-# libCufRuntime depends on a certain version of CUDA. To be able to have
+# libflang_rt.cuda depends on a certain version of CUDA. To be able to have
 # multiple build of this library with different CUDA version, the version is
 # added to the library name.
-set(CUFRT_LIBNAME CufRuntime_cuda_${CUDAToolkit_VERSION_MAJOR})
+set(CUFRT_LIBNAME flang_rt.cuda_${CUDAToolkit_VERSION_MAJOR})
 
 add_flang_library(${CUFRT_LIBNAME}
   allocator.cpp
@@ -33,6 +33,6 @@ endif()
 
 target_link_libraries(${CUFRT_LIBNAME}
   PRIVATE
-  FortranRuntime
+  flang_rt.runtime
   ${CUDA_RT_TARGET}
 )

flang/runtime/Float128Math/CMakeLists.txt

@@ -12,7 +12,7 @@
 # It is distributed as a static library only.
 # Fortran programs/libraries that end up linking any of the provided
 # will have a dependency on the third-party library that is being
-# used for building this FortranFloat128Math library.
+# used for building this flang_rt.quadmath library.
 
 include(CheckLibraryExists)
 
@@ -93,20 +93,20 @@ if (FLANG_RUNTIME_F128_MATH_LIB)
       )
   endif()
 
-  add_flang_library(FortranFloat128Math STATIC INSTALL_WITH_TOOLCHAIN
+  add_flang_library(flang_rt.quadmath STATIC INSTALL_WITH_TOOLCHAIN
     ${sources})
 
   if (DEFINED MSVC)
     set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreaded)
-    add_flang_library(FortranFloat128Math.static STATIC INSTALL_WITH_TOOLCHAIN
+    add_flang_library(flang_rt.quadmath.static STATIC INSTALL_WITH_TOOLCHAIN
       ${sources}
       )
     set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreadedDebug)
-    add_flang_library(FortranFloat128Math.static_dbg STATIC INSTALL_WITH_TOOLCHAIN
+    add_flang_library(flang_rt.quadmath.static_dbg STATIC INSTALL_WITH_TOOLCHAIN
       ${sources}
       )
-    add_dependencies(FortranFloat128Math FortranFloat128Math.static
-      FortranFloat128Math.static_dbg
+    add_dependencies(flang_rt.quadmath flang_rt.quadmath.static
+      flang_rt.quadmath.static_dbg
       )
   endif()
 elseif (HAVE_LDBL_MANT_DIG_113)
@@ -118,7 +118,7 @@ elseif (HAVE_LDBL_MANT_DIG_113)
       )
     target_sources(FortranFloat128MathILib INTERFACE ${sources})
   else()
-    message(FATAL_ERROR "FortranRuntime cannot build without libm")
+    message(FATAL_ERROR "flang_rt.quadmath cannot build without libm")
   endif()
 else()
   # We can use '__float128' version from libc, if it has them.

flang/runtime/time-intrinsic.cpp

@@ -62,7 +62,7 @@ template <typename Unused = void> double GetCpuTime(fallback_implementation) {
 
 #if defined __MINGW32__
 // clock_gettime is implemented in the pthread library for MinGW.
-// Using it here would mean that all programs that link libFortranRuntime are
+// Using it here would mean that all programs that link libflang_rt are
 // required to also link to pthread. Instead, don't use the function.
 #undef CLOCKID_CPU_TIME
 #undef CLOCKID_ELAPSED_TIME

flang/runtime/tools.h

@@ -348,7 +348,7 @@ inline RT_API_ATTRS RESULT ApplyFloatingPointKind(
     if constexpr (HasCppTypeFor<TypeCategory::Real, 16>) {
       // If FUNC implemenation relies on FP math functions,
       // then we should not be here. The compiler should have
-      // generated a call to an entry in FortranFloat128Math
+      // generated a call to an entry in flang_rt.quadmath
       // library.
       if constexpr (!NEEDSMATH) {
         return FUNC<16>{}(std::forward<A>(x)...);