[flang-commits] [clang] [flang] [Flang] [Option]To be compatible with classic flang, add the -Mextend compilation option (PR #173828)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-driver

Author: None (TZT123-a11y)

<details>
<summary>Changes</summary>

To maintain backward compatibility with the classic Flang compiler, support for the -Mextend compilation option has been added. Classic Flang uses the -Mextend option to allow fixed-format Fortran code to have a 132-column extended length, while modern Flang (based on LLVM) uses the -ffixed-line-length=132 option to achieve the same functionality.

---
Full diff: https://github.com/llvm/llvm-project/pull/173828.diff


3 Files Affected:

- (modified) clang/include/clang/Options/Options.td (+4) 
- (modified) clang/lib/Driver/ToolChains/Flang.cpp (+1) 
- (modified) flang/lib/Frontend/CompilerInvocation.cpp (+24-2) 


``````````diff
diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td
index e55146f0c7823..296c22006057d 100644
--- a/clang/include/clang/Options/Options.td
+++ b/clang/include/clang/Options/Options.td
@@ -7316,6 +7316,10 @@ def ffixed_line_length_EQ : Joined<["-"], "ffixed-line-length=">, Group<f_Group>
   DocBrief<[{Set column after which characters are ignored in typical fixed-form lines in the source
 file}]>;
 def ffixed_line_length_VALUE : Joined<["-"], "ffixed-line-length-">, Group<f_Group>, Alias<ffixed_line_length_EQ>;
+// modify for dcc
+def Mextend : Flag<["-"], "Mextend">, Group<f_Group>,
+  HelpText<"Classic Flang compat: Allow 132-column lines in fixed form">,
+  Visibility<[FC1Option, FlangOption]>;
 def fconvert_EQ : Joined<["-"], "fconvert=">, Group<f_Group>,
   HelpText<"Set endian conversion of data for unformatted files">;
 def fdefault_double_8 : Flag<["-"],"fdefault-double-8">, Group<f_Group>,
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 2f5e93d139858..0570e830f26f3 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -38,6 +38,7 @@ void Flang::addFortranDialectOptions(const ArgList &Args,
                                      ArgStringList &CmdArgs) const {
   Args.addAllArgs(CmdArgs, {options::OPT_ffixed_form,
                             options::OPT_ffree_form,
+                            options::OPT_Mextend, // modify for dcc
                             options::OPT_ffixed_line_length_EQ,
                             options::OPT_fopenacc,
                             options::OPT_finput_charset_EQ,
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index b6c4e6303cdac..83d7d29fc13aa 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1526,10 +1526,32 @@ static bool parseLangOptionsArgs(CompilerInvocation &invoc,
   return success;
 }
 
+// modify for dcc: begin
+static llvm::SmallVector<const char *>
+replaceClassicFlangArgs(llvm::ArrayRef<const char *> CommandLineArgs) {
+  llvm::SmallVector<const char *> NewArgs;
+  for (auto Arg : CommandLineArgs) {
+    // Process -mextend -> mapping to -ffixed-line-length=132
+    if (std::strcmp(Arg, "-Mextend") == 0) {
+      NewArgs.push_back("-ffixed-line-length=132");
+    }
+    else {
+    	NewArgs.push_back(Arg);
+    }
+  }
+  return NewArgs;
+}
+// modify for dcc: end
+
 bool CompilerInvocation::createFromArgs(
-    CompilerInvocation &invoc, llvm::ArrayRef<const char *> commandLineArgs,
+    CompilerInvocation &invoc, llvm::ArrayRef<const char *> commandLineArgs0,
     clang::DiagnosticsEngine &diags, const char *argv0) {
-
+  // modify for dcc: begin
+  auto NewCommandLineArgs =
+      replaceClassicFlangArgs(commandLineArgs0);
+  llvm::ArrayRef<const char *> commandLineArgs = NewCommandLineArgs;
+  // modify for dcc: end
+  
   bool success = true;
 
   // Set the default triple for this CompilerInvocation. This might be

``````````

</details>


https://github.com/llvm/llvm-project/pull/173828