ELF2: Support reponse files.

[ruiu]

Summary

Replace command line arguments starting with '@' with their file contents.

[shankare]

ELF/DriverUtils.cpp

58–60

Can you add the option @ to the help ?

[ruiu]

That's not a command line option but a meta-feature of that, so there's no
way to define an error message. Old LLD and Clang don't also print out a
help message for @, so it's probably not needed.

[shankare]

Thanks for the info, LGTM.

[• rafael]

+ Creates a new command line by replacing options starting with '@'
+ character. '@<filename>' is replaced by the file's contents.
+std::vector<const char *>
+ArgParser::replaceResponseFiles(ArrayRef<const char *> Argv) {
+ SmallVector<const char *, 256> Tokens(Argv.data(), Argv.data() + Argv.size());
+ StringSaver S(Alloc);
+ llvm:🆑:ExpandResponseFiles(S, llvm:🆑:TokenizeGNUCommandLine, Tokens);
+ return std::vector<const char *>(Tokens.begin(), Tokens.end());
+}

Can you pass in a SmallVectorImpl& instead? Not much point in
collecting results in the stack just to copy them to the heap.

LGTM with that.

Cheers,
Rafael

[Eugene.Zelenko]

Committed in r248575.

ELF/Driver.h

 
 // Entry point of the ELF linker.
 void link(ArrayRef<const char *> Args);
 
 class ArgParser {
 public:
   // Parses command line options.
   llvm::opt::InputArgList parse(ArrayRef<const char *> Args);
+
+private:
+  std::vector<const char *> replaceResponseFiles(ArrayRef<const char *> Args);
+  llvm::BumpPtrAllocator Alloc;
 };
 
 class LinkerDriver {
 public:
   void link(ArrayRef<const char *> Args);
 
 private:
   ArgParser Parser;

ELF/DriverUtils.cpp

 // are so many small functions, we created this separate file to make
 // Driver.cpp less cluttered.
 //
 //===----------------------------------------------------------------------===//
 
 #include "Driver.h"
 #include "Error.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/StringSaver.h"
 
 using namespace llvm;
 
 using namespace lld;
 using namespace lld::elf2;
 
 // Create OptTable
 

 
 // Parses a given list of options.
 opt::InputArgList ArgParser::parse(ArrayRef<const char *> Argv) {
   // Make InputArgList from string vectors.
   ELFOptTable Table;
   unsigned MissingIndex;
   unsigned MissingCount;
 
-  opt::InputArgList Args = Table.ParseArgs(Argv, MissingIndex, MissingCount);
+  std::vector<const char *> ArgvVec = replaceResponseFiles(Argv);
+  opt::InputArgList Args = Table.ParseArgs(ArgvVec, MissingIndex, MissingCount);
   if (MissingCount)
     error(Twine("missing arg value for \"") + Args.getArgString(MissingIndex) +
           "\", expected " + Twine(MissingCount) +
           (MissingCount == 1 ? " argument.\n" : " arguments"));
 
   iterator_range<opt::arg_iterator> Unknowns = Args.filtered(OPT_UNKNOWN);
   for (auto *Arg : Unknowns)
     warning("warning: unknown argument: " + Arg->getSpelling());
   if (Unknowns.begin() != Unknowns.end())
     error("unknown argument(s) found");
 
   return Args;
 }
+
+// Creates a new command line by replacing options starting with '@'
+// character. '@<filename>' is replaced by the file's contents.
+std::vector<const char *>
+ArgParser::replaceResponseFiles(ArrayRef<const char *> Argv) {
+  SmallVector<const char *, 256> Tokens(Argv.data(), Argv.data() + Argv.size());
+  StringSaver S(Alloc);
+  llvm::cl::ExpandResponseFiles(S, llvm::cl::TokenizeGNUCommandLine, Tokens);
+  return std::vector<const char *>(Tokens.begin(), Tokens.end());
+}

test/elf2/basic.s

 # CHECK-NEXT:     Flags [ (0x5)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:       PF_X (0x1)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 
+# RUN: echo " -o %t2" > %t.responsefile
+# RUN: lld -flavor gnu2 %t @%t.responsefile
+# RUN: llvm-readobj -file-headers -sections -program-headers -symbols %t2 \
+# RUN:   | FileCheck %s
+
 # RUN: not lld -flavor gnu2 %t 2>&1 | FileCheck --check-prefix=NO_O %s
 # NO_O: -o must be specified.
 
 # RUN: not lld -flavor gnu2 %t.foo -o %t2 2>&1 | \
 # RUN:  FileCheck --check-prefix=MISSING %s
 # MISSING: cannot open {{.*}}.foo: {{[Nn]}}o such file or directory
 
 # RUN: not lld -flavor gnu2 -o %t2 2>&1 | \