[PATCH] D25263: [Driver] Allow setting the default linker during build

[Petr Hosek via cfe-commits]

phosek created this revision.
phosek added a subscriber: cfe-commits.
phosek set the repository for this revision to rL LLVM.
Herald added subscribers: mgorny, beanz.

This change allows setting the default linker used by the Clang driver when configuring the build.


Repository:
  rL LLVM

https://reviews.llvm.org/D25263

Files:
  CMakeLists.txt
  include/clang/Config/config.h.cmake
  lib/Driver/ToolChain.cpp


Index: lib/Driver/ToolChain.cpp
===================================================================
--- lib/Driver/ToolChain.cpp
+++ lib/Driver/ToolChain.cpp
@@ -341,31 +341,29 @@
 }
 
 std::string ToolChain::GetLinkerPath() const {
-  if (Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
-    StringRef UseLinker = A->getValue();
-
-    if (llvm::sys::path::is_absolute(UseLinker)) {
-      // If we're passed -fuse-ld= with what looks like an absolute path,
-      // don't attempt to second-guess that.
-      if (llvm::sys::fs::exists(UseLinker))
-        return UseLinker;
-    } else {
-      // If we're passed -fuse-ld= with no argument, or with the argument ld,
-      // then use whatever the default system linker is.
-      if (UseLinker.empty() || UseLinker == "ld")
-        return GetProgramPath("ld");
-
-      llvm::SmallString<8> LinkerName("ld.");
-      LinkerName.append(UseLinker);
-
-      std::string LinkerPath(GetProgramPath(LinkerName.c_str()));
-      if (llvm::sys::fs::exists(LinkerPath))
-        return LinkerPath;
-    }
+  const Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ);
+  StringRef UseLinker = A ? A->getValue() : CLANG_DEFAULT_LINKER;
+
+  if (llvm::sys::path::is_absolute(UseLinker)) {
+    // If we're passed -fuse-ld= with what looks like an absolute path,
+    // don't attempt to second-guess that.
+    if (llvm::sys::fs::exists(UseLinker))
+      return UseLinker;
+  } else if (A && (UseLinker.empty() || UseLinker == "ld")) {
+    // If we're passed -fuse-ld= with no argument, or with the argument ld,
+    // then use whatever the default system linker is.
+    return GetProgramPath("ld");
+  } else if (!UseLinker.empty()) {
+    llvm::SmallString<8> LinkerName("ld.");
+    LinkerName.append(UseLinker);
+
+    std::string LinkerPath(GetProgramPath(LinkerName.c_str()));
+    if (llvm::sys::fs::exists(LinkerPath))
+      return LinkerPath;
+  }
 
+  if (A)
     getDriver().Diag(diag::err_drv_invalid_linker_name) << A->getAsString(Args);
-    return "";
-  }
 
   return GetProgramPath(DefaultLinker);
 }
Index: include/clang/Config/config.h.cmake
===================================================================
--- include/clang/Config/config.h.cmake
+++ include/clang/Config/config.h.cmake
@@ -8,6 +8,9 @@
 /* Bug report URL. */
 #define BUG_REPORT_URL "${BUG_REPORT_URL}"
 
+/* Default linker to use. */
+#define CLANG_DEFAULT_LINKER "${CLANG_DEFAULT_LINKER}"
+
 /* Default C++ stdlib to use. */
 #define CLANG_DEFAULT_CXX_STDLIB "${CLANG_DEFAULT_CXX_STDLIB}"
 
Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -195,6 +195,17 @@
 set(ENABLE_X86_RELAX_RELOCATIONS OFF CACHE BOOL
     "enable x86 relax relocations by default")
 
+set(CLANG_DEFAULT_LINKER "" CACHE STRING
+  "Default linker to use (\"bfd\" or \"gold\" or \"lld\", empty for platform default")
+if (NOT(CLANG_DEFAULT_LINKER STREQUAL "" OR
+        CLANG_DEFAULT_LINKER STREQUAL "bfd" OR
+        CLANG_DEFAULT_LINKER STREQUAL "gold" OR
+        CLANG_DEFAULT_LINKER STREQUAL "lld"))
+  message(WARNING "Resetting default linker to use platform default")
+  set(CLANG_DEFAULT_LINKER "" CACHE STRING
+    "Default linker to use (\"bfd\" or \"gold\" or \"lld\", empty for platform default" FORCE)
+endif()
+
 set(CLANG_DEFAULT_CXX_STDLIB "" CACHE STRING
   "Default C++ stdlib to use (\"libstdc++\" or \"libc++\", empty for platform default")
 if (NOT(CLANG_DEFAULT_CXX_STDLIB STREQUAL "" OR


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D25263.73589.patch
Type: text/x-patch
Size: 3508 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20161005/8f1aeeb9/attachment-0001.bin>