[PATCH] D117284: [ELF] Allow non-bitcode archive with an empty index

[Fangrui Song via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGd838bf2adc9c: [ELF] Allow non-bitcode archive with an empty index (authored by MaskRay).

Changed prior to commit:
  https://reviews.llvm.org/D117284?vs=400898&id=401303#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D117284/new/

https://reviews.llvm.org/D117284

Files:
  lld/ELF/Driver.cpp
  lld/test/ELF/archive-no-index.s
  lld/test/ELF/lto/archive-no-index.ll


Index: lld/test/ELF/lto/archive-no-index.ll
===================================================================
--- lld/test/ELF/lto/archive-no-index.ll
+++ lld/test/ELF/lto/archive-no-index.ll
@@ -1,6 +1,5 @@
 ; REQUIRES: x86
-; Tests that we accept an archive file without symbol table
-; if all the member files are bitcode files.
+; Tests that we accept an archive file without symbol table.
 
 ; RUN: llvm-as -o %t1.o %s
 ; RUN: llvm-as -o %t2.o %S/Inputs/archive.ll
@@ -25,8 +24,7 @@
 ; RUN: echo 'f:' | llvm-mc -triple=x86_64-pc-linux -filetype=obj - -o %t3.o
 ; RUN: rm -f %t3.a
 ; RUN: llvm-ar crS %t3.a %t3.o
-; RUN: not ld.lld -o /dev/null -emain %t1.o %t3.a 2>&1 | FileCheck -check-prefix=ERR1 %s
-; ERR1: error: {{.*}}.a: archive has no index; run ranlib to add one
+; RUN: not ld.lld -o %t -emain %t1.o %t3.a 2>&1 | FileCheck --check-prefix=ERR2 %s
 
 ; RUN: rm -f %t4.a
 ; RUN: llvm-ar cr %t4.a
Index: lld/test/ELF/archive-no-index.s
===================================================================
--- lld/test/ELF/archive-no-index.s
+++ lld/test/ELF/archive-no-index.s
@@ -5,9 +5,13 @@
 # RUN: rm -f %t.a
 # RUN: llvm-ar crS %t.a %t.archive.o
 
-# RUN: not ld.lld -o /dev/null %t.o %t.a 2>&1 | FileCheck %s
+# RUN: ld.lld %t.o %t.a -o /dev/null 2>&1 | count 0
+
+# RUN: ld.lld -shared %t.archive.o -o %t.so
+# RUN: llvm-ar crS %t.a %t.so
+# RUN: not ld.lld %t.o %t.a --noinhibit-exec -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR
+
+# ERR: error: {{.*}}.a: archive member '{{.*}}.so' is neither ET_REL nor LLVM bitcode
 
 .globl _start
 _start:
-
-# CHECK: error: {{.*}}.a: archive has no index; run ranlib to add one
Index: lld/ELF/Driver.cpp
===================================================================
--- lld/ELF/Driver.cpp
+++ lld/ELF/Driver.cpp
@@ -235,23 +235,22 @@
     std::unique_ptr<Archive> file =
         CHECK(Archive::create(mbref), path + ": failed to parse archive");
 
-    // If an archive file has no symbol table, it is likely that a user
-    // is attempting LTO and using a default ar command that doesn't
-    // understand the LLVM bitcode file. It is a pretty common error, so
-    // we'll handle it as if it had a symbol table.
+    // If an archive file has no symbol table, it may be intentional (used as a
+    // group of lazy object files where the symbol table is not useful), or the
+    // user is attempting LTO and using a default ar command that doesn't
+    // understand the LLVM bitcode file. Treat the archive as a group of lazy
+    // object files.
     if (!file->isEmpty() && !file->hasSymbolTable()) {
-      // Check if all members are bitcode files. If not, ignore, which is the
-      // default action without the LTO hack described above.
       for (const std::pair<MemoryBufferRef, uint64_t> &p :
-           getArchiveMembers(mbref))
-        if (identify_magic(p.first.getBuffer()) != file_magic::bitcode) {
-          error(path + ": archive has no index; run ranlib to add one");
-          return;
-        }
-
-      for (const std::pair<MemoryBufferRef, uint64_t> &p :
-           getArchiveMembers(mbref))
-        files.push_back(createLazyFile(p.first, path, p.second));
+           getArchiveMembers(mbref)) {
+        auto magic = identify_magic(p.first.getBuffer());
+        if (magic == file_magic::bitcode ||
+            magic == file_magic::elf_relocatable)
+          files.push_back(createLazyFile(p.first, path, p.second));
+        else
+          error(path + ": archive member '" + p.first.getBufferIdentifier() +
+                "' is neither ET_REL nor LLVM bitcode");
+      }
       return;
     }
 


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