[PATCH] D81124: lld: use modern library search ordering

[Saleem Abdulrasool via Phabricator via llvm-commits]

compnerd created this revision.
compnerd added reviewers: smeenai, int3, lld-macho.
compnerd added a project: lld.
Herald added a project: LLVM.

This merges the static and shared library and behaves as if
`-search_paths_first` was specified which is also the default beahviour
on ld64 (and now lld).  Unify the paths, and use `llvm::sys::path` to
deal with the path to be truly agnostic to the host.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D81124

Files:
  lld/MachO/Driver.cpp
  lld/test/MachO/link-search-order.s


Index: lld/test/MachO/link-search-order.s
===================================================================
--- /dev/null
+++ lld/test/MachO/link-search-order.s
@@ -0,0 +1,39 @@
+# RUN: mkdir -p %t
+# RUN: llvm-mc -filetype obj -triple x86_64-apple-darwin %p/Inputs/libhello.s -o %t/hello.o
+# RUN: llvm-mc -filetype obj -triple x86_64-apple-darwin %p/Inputs/libgoodbye.s -o %t/goodbye.o
+# RUN: lld -flavor darwinnew -dylib -install_name @executable_path/libhello.dylib %t/hello.o -o %t/libhello.dylib
+# RUN: lld -flavor darwinnew -dylib -install_name @executable_path/libgoodbye.dylib %t/goodbye.o -o %t/libgoodbye.dylib
+# RUN: llvm-ar --format=darwin crs %t/libgoodbye.a %t/goodbye.o
+# RUN: llvm-mc -filetype obj -triple x86_64-apple-darwin %s -o %t/test.o
+# RUN: lld -flavor darwinnew -o %t/test -Z -L%t -lhello -lgoodbye %t/test.o
+# RUN: llvm-objdump --macho --dylibs-used %t/test | FileCheck %s
+
+# REQUIRES: x86
+
+# CHECK: @executable_path/libhello.dylib
+# CHECK: @executable_path/libgoodbye.dylib
+# CHECK: /usr/lib/libSystem.B.dylib
+
+.section __TEXT,__text
+.global _main
+
+_main:
+  movl $0x2000004, %eax                                # write()
+  mov $1, %rdi                                 # stdout
+  movq _hello_world at GOTPCREL(%rip), %rsi
+  mov $13, %rdx                                        # length
+  syscall
+
+  movl $0x2000004, %eax                                # write()
+  mov $1, %rdi                                 # stdout
+  movq _hello_its_me at GOTPCREL(%rip), %rsi
+  mov $15, %rdx                                        # length
+  syscall
+
+  movl $0x2000004, %eax                                # write()
+  mov $1, %rdi                                 # stdout
+  movq _goodbye_world at GOTPCREL(%rip), %rsi
+  mov $15, %rdx                                        # length
+  syscall
+  mov $0, %rax
+  ret
Index: lld/MachO/Driver.cpp
===================================================================
--- lld/MachO/Driver.cpp
+++ lld/MachO/Driver.cpp
@@ -73,21 +73,18 @@
   return args;
 }
 
-// This is for -lfoo. We'll look for libfoo.dylib from search paths.
-static Optional<std::string> findDylib(StringRef name) {
-  for (StringRef dir : config->searchPaths) {
-    std::string path = (dir + "/lib" + name + ".dylib").str();
-    if (fs::exists(path))
-      return path;
-  }
-  return None;
-}
+static Optional<std::string> findLibrary(StringRef name) {
+  std::string shared = (llvm::Twine("lib") + name + ".dylib").str();
+  std::string archive = (llvm::Twine("lib") + name + ".a").str();
+  llvm::SmallString<260> location;
 
-static Optional<std::string> findArchive(StringRef name) {
   for (StringRef dir : config->searchPaths) {
-    std::string path = (dir + "/lib" + name + ".a").str();
-    if (fs::exists(path))
-      return path;
+    for (StringRef library : { shared, archive }) {
+      location = dir;
+      llvm::sys::path::append(location, library);
+      if (fs::exists(location))
+        return location.str().str();
+    }
   }
   return None;
 }
@@ -296,12 +293,11 @@
       break;
     case OPT_l: {
       StringRef name = arg->getValue();
-      if (Optional<std::string> path = findDylib(name))
+      if (Optional<std::string> path = findLibrary(name)) {
         addFile(*path);
-      else if (Optional<std::string> path = findArchive(name))
-        addFile(*path);
-      else
-        error("library not found for -l" + name);
+        break;
+      }
+      error("library not found for -l" + name);
       break;
     }
     case OPT_platform_version: {


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