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

Since GNU ar 2.31, the 't' operation prints member offsets beside file
names if the 'O' modifier is specified. 'O' is ignored for thin
archives.

Reviewed By: gbreynoo, ruiu

Differential Revision: https://reviews.llvm.org/D69087

llvm-svn: 375106

docs/CommandGuide/llvm-ar.rst

@@ -100,15 +100,15 @@ r[abu]
  *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]
 
@@ -145,6 +145,10 @@ section (above) to determine which modifiers are applicable to which operations.
  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

include/llvm/Object/Archive.h

@@ -135,6 +135,7 @@ public:
 
     Expected<StringRef> getBuffer() const;
     uint64_t getChildOffset() const;
+    uint64_t getDataOffset() const { return getChildOffset() + StartOfFile; }
 
     Expected<MemoryBufferRef> getMemoryBufferRef() const;
 

test/Object/archive-thin-create.test

@@ -9,6 +9,9 @@ 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

@@ -46,3 +46,17 @@ RUN: env TZ=GMT llvm-ar tv Inputs/thin-path.a | FileCheck %s --check-prefix=THIN
 
 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

@@ -106,6 +106,7 @@ MODIFIERS:
   [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
@@ -187,17 +188,18 @@ enum ArchiveOperation {
 };
 
 // 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
@@ -329,6 +331,9 @@ static ArchiveOperation parseCommandLine() {
     case 'o':
       OriginalDates = true;
       break;
+    case 'O':
+      DisplayMemberOffsets = true;
+      break;
     case 'P':
       CompareFullPath = true;
       break;
@@ -486,8 +491,13 @@ static void doDisplayTable(StringRef Name, const object::Archive::Child &C) {
       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) {