[llvm-ar] Implement the O modifier: display member offsets inside the archive

[MaskRay]

Summary

Since GNU ar 2.31, 'O' prints member offsets beside file names.
It is ignored for thin archives.

[ruiu]

LGTM

tools/llvm-ar/llvm-ar.cpp

498

This code surprised me a little bit, although it is correct. I'd use utohexstr and operator<< instead of raw_ostream::write_hex.

[grandinj]

docs/CommandGuide/llvm-ar.rst

150

arhive->archive

tools/llvm-ar/llvm-ar.cpp

191

DisplayOffsets -> DisplayMemberOffsets ?

"offsets" is a rather generic thing

[MaskRay]

Address review comments

1. (outs() << " 0x").write_hex(C.getDataOffset());

>

outs() << (" 0x" + utohexstr(C.getDataOffset(), true));

2. DisplayOffsets -> DisplayMemberOffsets

[ruiu]

tools/llvm-ar/llvm-ar.cpp

498

The following style is more common. Doesn't this work?

outs() << " 0x" << utohexstr(C.getDataOffset(), true);

[MaskRay]

Use outs() << " 0x" << utohexstr(C.getDataOffset(), true);

[gbreynoo]

LGTM

[rupprecht]

Cool!

docs/CommandGuide/llvm-ar.rst

 
 r[abu]
 
  Replace or insert file members. The *a*, *b*,  and *u*
  modifiers apply to this operation. This operation will replace existing
  *files* or insert them at the end of the archive if they do not exist. If no
  *files* are specified, the archive is not modified.
 
-t[v]
+t[vO]
 
  Print the table of contents. Without any modifiers, this operation just prints
  the names of the members to the standard output. With the *v* modifier,
  **llvm-ar** also prints out the file type (B=bitcode, S=symbol
  table, blank=regular file), the permission mode, the owner and group, the
- size, and the date. If any *files* are specified, the listing is only for
- those files. If no *files* are specified, the table of contents for the
- whole archive is printed.
+ size, and the date. With the :option:`O` modifier, display member offsets.
+ If any *files* are specified, the listing is only for those files. If no
+ *files* are specified, the table of contents for the whole archive is printed.
 
 x[oP]
 
  Extract archive members back to files. The *o* modifier applies to this
  operation. This operation retrieves the indicated *files* from the archive
  and writes them back to the operating system's file system. If no
  *files* are specified, the entire archive is extract.
 

 
  A synonym for the *b* option.
 
 [o]
 
  When extracting files, this option will cause **llvm-ar** to preserve the
  original modification times of the files it writes.
 
+[O]
+
+ Display member offsets inside the archive.
+
 [u]
 
  When replacing existing files in the archive, only replace those files that have
  a time stamp than the time stamp of the member in the archive.
 
 Modifiers (generic)
 ~~~~~~~~~~~~~~~~~~~
 

include/llvm/Object/Archive.h

public:
 
     /// \return the size of the archive member without the header or padding.
     Expected<uint64_t> getSize() const;
     /// \return the size in the archive header for this member.
     Expected<uint64_t> getRawSize() const;
 
     Expected<StringRef> getBuffer() const;
     uint64_t getChildOffset() const;
+    uint64_t getDataOffset() const { return getChildOffset() + StartOfFile; }
 
     Expected<MemoryBufferRef> getMemoryBufferRef() const;
 
     Expected<std::unique_ptr<Binary>>
     getAsBinary(LLVMContext *Context = nullptr) const;
   };
 
   class ChildFallibleIterator {

test/Object/archive-thin-create.test

 RUN: rm -rf %t
 RUN: mkdir -p %t
 RUN: cd %t
 RUN: mkdir -p foo
 RUN: touch foo/test1.o
 RUN: touch foo/test2.o
 RUN: llvm-ar qcT foo/libtest.a foo/test1.o
 RUN: llvm-ar qcT foo/libtest.a foo/test1.o
 RUN: llvm-ar qcT foo/libtest.a foo/test2.o
 RUN: llvm-ar t foo/libtest.a | FileCheck --match-full-lines %s
 
+O (displaying member offsets) is ignored for thin archives.
+RUN: llvm-ar tO foo/libtest.a | FileCheck --match-full-lines %s
+
 CHECK: foo/test1.o
 CHECK: foo/test1.o
 CHECK: foo/test2.o
 

test/Object/archive-toc.test

 RUN: llvm-ar tv Inputs/symtab-only.a | FileCheck --allow-empty --check-prefix=EMPTY %s
 EMPTY-NOT: {{.}}
 
 Test reading a thin archive with directory names.
 RUN: env TZ=GMT llvm-ar tv Inputs/thin-path.a | FileCheck %s --check-prefix=THINPATH -strict-whitespace
 
 THINPATH:      rw-r--r-- 0/0   1224 Jan  1 00:00 1970 Inputs/test.o
 THINPATH-NEXT: rw-r--r-- 0/0   1224 Jan  1 00:00 1970 Inputs/t/test2.o
+
+RUN: llvm-ar tO Inputs/GNU.a | FileCheck %s --check-prefix=GNU-O --strict-whitespace
+
+GNU-O:      {{^}}evenlen 0x10c
+GNU-O-NEXT: {{^}}oddlen 0x150
+GNU-O-NEXT: {{^}}very_long_bytecode_file_name.bc 0x194
+GNU-O-NEXT: {{^}}IsNAN.o 0x78a
+
+RUN: env TZ=GMT llvm-ar tvO Inputs/GNU.a | FileCheck %s --check-prefix=GNU-VO --strict-whitespace
+
+GNU-VO:      rw-r--r-- 500/500      8 Nov 19 02:57 2004 evenlen 0x10c
+GNU-VO-NEXT: rw-r--r-- 500/500      7 Nov 19 02:57 2004 oddlen 0x150
+GNU-VO-NEXT: rwxr-xr-x 500/500   1465 Nov 19 03:01 2004 very_long_bytecode_file_name.bc 0x194
+GNU-VO-NEXT: rw-r--r-- 500/500   2280 Nov 19 03:04 2004 IsNAN.o 0x78a

tools/llvm-ar/llvm-ar.cpp

MODIFIERS:
   [c] - do not warn if archive had to be created
   [D] - use zero for timestamps and uids/gids (default)
   [h] - display this help and exit
   [i] - put [files] before [relpos] (same as [b])
   [l] - ignored for compatibility
   [L] - add archive's contents
   [N] - use instance [count] of name
   [o] - preserve original dates
+  [O] - display member offsets
   [P] - use full names when matching (implied for thin archives)
   [s] - create an archive index (cf. ranlib)
   [S] - do not build a symbol table
   [T] - create a thin archive
   [u] - update only [files] newer than archive contents
   [U] - use actual timestamps and uids/gids
   [v] - be verbose about actions taken
   [V] - display the version and exit
enum ArchiveOperation {
   QuickAppend,     ///< Quickly append to end of archive
   ReplaceOrInsert, ///< Replace or Insert members
   DisplayTable,    ///< Display the table of contents
   Extract,         ///< Extract files back to file system
   CreateSymTab     ///< Create a symbol table in an existing archive
 };
 
 // Modifiers to follow operation to vary behavior
-static bool AddAfter = false;        ///< 'a' modifier
-static bool AddBefore = false;       ///< 'b' modifier
-static bool Create = false;          ///< 'c' modifier
-static bool OriginalDates = false;   ///< 'o' modifier
-static bool CompareFullPath = false; ///< 'P' modifier
-static bool OnlyUpdate = false;      ///< 'u' modifier
-static bool Verbose = false;         ///< 'v' modifier
-static bool Symtab = true;           ///< 's' modifier
-static bool Deterministic = true;    ///< 'D' and 'U' modifiers
-static bool Thin = false;            ///< 'T' modifier
-static bool AddLibrary = false;      ///< 'L' modifier
+static bool AddAfter = false;             ///< 'a' modifier
+static bool AddBefore = false;            ///< 'b' modifier
+static bool Create = false;               ///< 'c' modifier
+static bool OriginalDates = false;        ///< 'o' modifier
+static bool DisplayMemberOffsets = false; ///< 'O' modifier
+static bool CompareFullPath = false;      ///< 'P' modifier
+static bool OnlyUpdate = false;           ///< 'u' modifier
+static bool Verbose = false;              ///< 'v' modifier
+static bool Symtab = true;                ///< 's' modifier
+static bool Deterministic = true;         ///< 'D' and 'U' modifiers
+static bool Thin = false;                 ///< 'T' modifier
+static bool AddLibrary = false;           ///< 'L' modifier
 
 // Relative Positional Argument (for insert/move). This variable holds
 // the name of the archive member to which the 'a', 'b' or 'i' modifier
 // refers. Only one of 'a', 'b' or 'i' can be specified so we only need
 // one variable.
 static std::string RelPos;
 
 // Count parameter for 'N' modifier. This variable specifies which file should
for (unsigned i = 0; i < Options.size(); ++i) {
     case 'c':
       Create = true;
       break;
     case 'l': /* accepted but unused */
       break;
     case 'o':
       OriginalDates = true;
       break;
+    case 'O':
+      DisplayMemberOffsets = true;
+      break;
     case 'P':
       CompareFullPath = true;
       break;
     case 's':
       Symtab = true;
       MaybeJustCreateSymTab = true;
       break;
     case 'S':
static void doDisplayTable(StringRef Name, const object::Archive::Child &C) {
   }
 
   if (C.getParent()->isThin()) {
     if (!sys::path::is_absolute(Name)) {
       StringRef ParentDir = sys::path::parent_path(ArchiveName);
       if (!ParentDir.empty())
         outs() << sys::path::convert_to_slash(ParentDir) << '/';
     }
+    outs() << Name;
+  } else {
+    outs() << Name;
+    if (DisplayMemberOffsets)
+      outs() << (" 0x" + utohexstr(C.getDataOffset(), true));
   }
-  outs() << Name << "\n";
+  outs() << '\n';
 }
 
 static std::string normalizePath(StringRef Path) {
   return CompareFullPath ? sys::path::convert_to_slash(Path)
                          : std::string(sys::path::filename(Path));
 }
 
 static bool comparePaths(StringRef Path1, StringRef Path2) {