Flang implementation for COMPILER_VERSION and COMPILER_OPTIONS intrinsics

This revision implements the Fortran intrinsic procedures COMPILER_VERSION and COMPILER_OPTIONS from the iso_fortran_env module.
To be able to set the COMPILER_OPTIONS string according to the original compiler driver invocation, a string is passed to the frontend driver using the environment variable FLANG_COMPILER_OPTIONS_STRING, for lack of a better mechanism.

Fixes #59233

Reviewed By: awarzynski

Differential Revision: https://reviews.llvm.org/D140524

2 files changed, 26 insertions, 2 deletions

diff --git a/flang/tools/flang-driver/driver.cpp b/flang/tools/flang-driver/driver.cpp
index a4c57f8..d8c597a 100644
--- a/flang/tools/flang-driver/driver.cpp
+++ b/flang/tools/flang-driver/driver.cpp
@@ -28,7 +28,9 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/VirtualFileSystem.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Host.h"
+#include <stdlib.h>
 
 using llvm::StringRef;
 
@@ -135,6 +137,28 @@ int main(int argc, const char **argv) {
   llvm::SmallVector<std::pair<int, const clang::driver::Command *>, 4>
       failingCommands;
 
+  // Set the environment variable, FLANG_COMPILER_OPTIONS_STRING, to contain all
+  // the compiler options. This is intended for the frontend driver,
+  // flang-new -fc1, to enable the implementation of the COMPILER_OPTIONS
+  // intrinsic. To this end, the frontend driver requires the list of the
+  // original compiler options, which is not available through other means.
+  // TODO: This way of passing information between the compiler and frontend
+  // drivers is discouraged. We should find a better way not involving env
+  // variables.
+  std::string compilerOptsGathered;
+  llvm::raw_string_ostream os(compilerOptsGathered);
+  for (int i = 0; i < argc; ++i) {
+    os << argv[i];
+    if (i < argc - 1) {
+      os << ' ';
+    }
+  }
+#ifdef _WIN32
+  _putenv_s("FLANG_COMPILER_OPTIONS_STRING", compilerOptsGathered.c_str());
+#else
+  setenv("FLANG_COMPILER_OPTIONS_STRING", compilerOptsGathered.c_str(), 1);
+#endif
+
   // Run the driver
   int res = 1;
   bool isCrash = false;
diff --git a/flang/tools/flang-driver/fc1_main.cpp b/flang/tools/flang-driver/fc1_main.cpp
index d9c9881..b5b062a 100644
--- a/flang/tools/flang-driver/fc1_main.cpp
+++ b/flang/tools/flang-driver/fc1_main.cpp
@@ -50,8 +50,8 @@ int fc1_main(llvm::ArrayRef<const char *> argv, const char *argv0) {
   llvm::IntrusiveRefCntPtr<clang::DiagnosticOptions> diagOpts =
       new clang::DiagnosticOptions();
   clang::DiagnosticsEngine diags(diagID, &*diagOpts, diagsBuffer);
-  bool success =
-      CompilerInvocation::createFromArgs(flang->getInvocation(), argv, diags);
+  bool success = CompilerInvocation::createFromArgs(flang->getInvocation(),
+                                                    argv, diags, argv0);
 
   // Initialize targets first, so that --version shows registered targets.
   llvm::InitializeAllTargets();