Make Linkerscript accessible from LinkingContext

[davide]

Summary

Put a pointer to linker script AST into the LinkingContext, so everyone can access linker script information.
This is the first step needed to implement semantic actions for Linker Script constructs.

[ruiu]

I'd avoid carrying around raw linker script information as much as possible because it's too low level. An AST of a linker script is raw information about the linker script, and this patch will make it visible to virtually everyone (because the linking context object is shared by all components). It feels to me that this patch makes the information to be shared too broadly.

I made a change to interpret a linker script in the driver. I'd interpret linker scripts only in the driver and set cooked information to the linking context, instead of raw data. Is there any reason you can't do that way?

[davide]

I can do that way, and I probably should. Close this.

include/lld/Core/LinkingContext.h

 #include "lld/Core/Reference.h"
 #include "lld/Core/range.h"
 #include "lld/Core/Reader.h"
+#include "lld/ReaderWriter/LinkerScript.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/raw_ostream.h"
 #include <string>

 
   TaskGroup &getTaskGroup() { return _taskGroup; }
 
+  // LinkerScript
+  script::LinkerScript *getLinkerScriptAST() { return _linkerScript; };
+
+  void setLinkerScriptAST(script::LinkerScript *script) {
+    _linkerScript = script;
+  }
+
   /// @}
 protected:
   LinkingContext(); // Must be subclassed

   /// Method to create an internal file for alias symbols
   std::unique_ptr<File> createAliasSymbolFile() const;
 
+  script::LinkerScript *_linkerScript;
   StringRef _outputPath;
   StringRef _entrySymbolName;
   bool _deadStrip;

lib/Driver/GnuLdDriver.cpp

     if (auto *group = dyn_cast<script::Group>(c))
       if (std::error_code ec = evaluateLinkerScriptGroup(ctx, path, group, diag))
         return ec;
+
+  // LinkerScript is now accessible from LinkingContext.
+  ctx.setLinkerScriptAST(script);
   return std::error_code();
 }