[llvm] r336943 - [gold-plugin] Disable section ordering for relocatable links

[Bill Wendling via llvm-commits]

Author: void
Date: Thu Jul 12 13:35:58 2018
New Revision: 336943

URL: http://llvm.org/viewvc/llvm-project?rev=336943&view=rev
Log:
[gold-plugin] Disable section ordering for relocatable links

Not all programs want section ordering when compiled with LTO.
In particular, the Linux kernel is very sensitive when it comes to linking, and
doesn't boot when each function is placed in its own sections.

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D48756

Modified:
    llvm/trunk/test/tools/gold/X86/relocatable.ll
    llvm/trunk/tools/gold/gold-plugin.cpp

Modified: llvm/trunk/test/tools/gold/X86/relocatable.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/gold/X86/relocatable.ll?rev=336943&r1=336942&r2=336943&view=diff
==============================================================================
--- llvm/trunk/test/tools/gold/X86/relocatable.ll (original)
+++ llvm/trunk/test/tools/gold/X86/relocatable.ll Thu Jul 12 13:35:58 2018
@@ -10,7 +10,7 @@
 ; CHECK-NEXT:   Binding: Global
 ; CHECK-NEXT:   Type: Function
 ; CHECK-NEXT:   Other: 0
-; CHECK-NEXT:   Section: .text.foo
+; CHECK-NEXT:   Section: .text
 ; CHECK-NEXT: }
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

Modified: llvm/trunk/tools/gold/gold-plugin.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/gold/gold-plugin.cpp?rev=336943&r1=336942&r2=336943&view=diff
==============================================================================
--- llvm/trunk/tools/gold/gold-plugin.cpp (original)
+++ llvm/trunk/tools/gold/gold-plugin.cpp Thu Jul 12 13:35:58 2018
@@ -115,6 +115,7 @@ static ld_plugin_add_input_file add_inpu
 static ld_plugin_set_extra_library_path set_extra_library_path = nullptr;
 static ld_plugin_get_view get_view = nullptr;
 static bool IsExecutable = false;
+static bool SplitSections = true;
 static Optional<Reloc::Model> RelocationModel = None;
 static std::string output_name = "";
 static std::list<claimed_file> Modules;
@@ -324,6 +325,7 @@ ld_plugin_status onload(ld_plugin_tv *tv
       switch (tv->tv_u.tv_val) {
       case LDPO_REL: // .o
         IsExecutable = false;
+        SplitSections = false;
         break;
       case LDPO_DYN: // .so
         IsExecutable = false;
@@ -834,9 +836,9 @@ static std::unique_ptr<LTO> createLTO(In
   // FIXME: Check the gold version or add a new option to enable them.
   Conf.Options.RelaxELFRelocations = false;
 
-  // Enable function/data sections by default.
-  Conf.Options.FunctionSections = true;
-  Conf.Options.DataSections = true;
+  // Toggle function/data sections.
+  Conf.Options.FunctionSections = SplitSections;
+  Conf.Options.DataSections = SplitSections;
 
   Conf.MAttrs = MAttrs;
   Conf.RelocModel = RelocationModel;