9 files changed, 44 insertions, 0 deletions
diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 3189145326b..f95e72bef6d 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -143,6 +143,8 @@ def mno_exec_stack : Flag<["-"], "mnoexecstack">,
   HelpText<"Mark the file as not needing an executable stack">;
 def massembler_fatal_warnings : Flag<["-"], "massembler-fatal-warnings">,
   HelpText<"Make assembler warnings fatal">;
+def mrelax_relocations : Flag<["--"], "mrelax-relocations">,
+    HelpText<"Use relaxabel elf relocations">;
 def compress_debug_sections : Flag<["-"], "compress-debug-sections">,
     HelpText<"Compress DWARF debug sections using zlib">;
 def msave_temp_labels : Flag<["-"], "msave-temp-labels">,
diff --git a/clang/include/clang/Frontend/CodeGenOptions.def b/clang/include/clang/Frontend/CodeGenOptions.def
index 2e2344a8e4a..ca81964df0e 100644
--- a/clang/include/clang/Frontend/CodeGenOptions.def
+++ b/clang/include/clang/Frontend/CodeGenOptions.def
@@ -30,6 +30,7 @@ CODEGENOPT(Name, Bits, Default)
 
 CODEGENOPT(DisableIntegratedAS, 1, 0) ///< -no-integrated-as
 CODEGENOPT(CompressDebugSections, 1, 0) ///< -Wa,-compress-debug-sections
+CODEGENOPT(RelaxELFRelocations, 1, 0) ///< -Wa,--mrelax-relocations
 CODEGENOPT(AsmVerbose        , 1, 0) ///< -dA, -fverbose-asm.
 CODEGENOPT(AssumeSaneOperatorNew , 1, 1) ///< implicit __attribute__((malloc)) operator new
 CODEGENOPT(Autolink          , 1, 1) ///< -fno-autolink
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 2577eecdf84..0b0b5a764ad 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -593,6 +593,7 @@ TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
   Options.UseInitArray = CodeGenOpts.UseInitArray;
   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
   Options.CompressDebugSections = CodeGenOpts.CompressDebugSections;
+  Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
 
   // Set EABI version.
   Options.EABIVersion = llvm::StringSwitch<llvm::EABI>(TargetOpts.EABIVersion)
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 1c6082e3c58..c6edc2a14f6 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -2797,6 +2797,8 @@ static void CollectArgsForIntegratedAssembler(Compilation &C,
   // When using an integrated assembler, translate -Wa, and -Xassembler
   // options.
   bool CompressDebugSections = false;
+
+  bool UseRelaxRelocations = false;
   const char *MipsTargetFeature = nullptr;
   for (const Arg *A :
        Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler)) {
@@ -2872,6 +2874,12 @@ static void CollectArgsForIntegratedAssembler(Compilation &C,
       } else if (Value == "-nocompress-debug-sections" ||
                  Value == "--nocompress-debug-sections") {
         CompressDebugSections = false;
+      } else if (Value == "-mrelax-relocations=yes" ||
+                 Value == "--mrelax-relocations=yes") {
+        UseRelaxRelocations = true;
+      } else if (Value == "-mrelax-relocations=no" ||
+                 Value == "--mrelax-relocations=no") {
+        UseRelaxRelocations = false;
       } else if (Value.startswith("-I")) {
         CmdArgs.push_back(Value.data());
         // We need to consume the next argument if the current arg is a plain
@@ -2903,6 +2911,8 @@ static void CollectArgsForIntegratedAssembler(Compilation &C,
     else
       D.Diag(diag::warn_debug_compression_unavailable);
   }
+  if (UseRelaxRelocations)
+    CmdArgs.push_back("--mrelax-relocations");
   if (MipsTargetFeature != nullptr) {
     CmdArgs.push_back("-target-feature");
     CmdArgs.push_back(MipsTargetFeature);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 3b4c50b8356..4bb08c8a81c 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -683,6 +683,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.InstrumentForProfiling = Args.hasArg(OPT_pg);
   Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
   Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
+  Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
   for (auto A : Args.filtered(OPT_mlink_bitcode_file, OPT_mlink_cuda_bitcode)) {
     unsigned LinkFlags = llvm::Linker::Flags::None;
diff --git a/clang/test/CodeGen/relax.c b/clang/test/CodeGen/relax.c
new file mode 100644
index 00000000000..dd3ec4886bb
--- /dev/null
+++ b/clang/test/CodeGen/relax.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -emit-obj --mrelax-relocations %s -mrelocation-model pic -o %t
+// RUN: llvm-readobj -r %t | FileCheck  %s
+
+// CHECK: R_X86_64_REX_GOTPCRELX foo
+
+extern int foo;
+int *f(void) {
+  return &foo;
+}
diff --git a/clang/test/Driver/relax.c b/clang/test/Driver/relax.c
new file mode 100644
index 00000000000..170d2751b29
--- /dev/null
+++ b/clang/test/Driver/relax.c
@@ -0,0 +1,4 @@
+// RUN: %clang -### -c -integrated-as -Wa,--mrelax-relocations=yes %s 2>&1 | FileCheck  %s
+
+// CHECK: "-cc1"
+// CHECK: "--mrelax-relocations"
diff --git a/clang/test/Driver/relax.s b/clang/test/Driver/relax.s
new file mode 100644
index 00000000000..d2941e2f173
--- /dev/null
+++ b/clang/test/Driver/relax.s
@@ -0,0 +1,12 @@
+// REQUIRES: x86-registered-target
+// RUN: %clang -### -c -integrated-as -Wa,--mrelax-relocations=yes %s 2>&1 | FileCheck  %s
+
+// CHECK: "-cc1as"
+// CHECK: "--mrelax-relocations"
+
+// RUN: %clang -cc1as -triple x86_64-pc-linux --mrelax-relocations %s -o %t  -filetype obj
+// RUN: llvm-readobj -r %t | FileCheck --check-prefix=REL %s
+
+// REL: R_X86_64_REX_GOTPCRELX foo
+
+        movq	foo@GOTPCREL(%rip), %rax
diff --git a/clang/tools/driver/cc1as_main.cpp b/clang/tools/driver/cc1as_main.cpp
index 60ef7c96640..1c032c09ef6 100644
--- a/clang/tools/driver/cc1as_main.cpp
+++ b/clang/tools/driver/cc1as_main.cpp
@@ -88,6 +88,7 @@ struct AssemblerInvocation {
   unsigned SaveTemporaryLabels : 1;
   unsigned GenDwarfForAssembly : 1;
   unsigned CompressDebugSections : 1;
+  unsigned RelaxELFRelocations : 1;
   unsigned DwarfVersion;
   std::string DwarfDebugFlags;
   std::string DwarfDebugProducer;
@@ -200,6 +201,7 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
   // Any DebugInfoKind implies GenDwarfForAssembly.
   Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
   Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
+  Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
   Opts.DwarfDebugProducer = Args.getLastArgValue(OPT_dwarf_debug_producer);
@@ -315,6 +317,8 @@ static bool ExecuteAssembler(AssemblerInvocation &Opts,
   if (Opts.CompressDebugSections)
     MAI->setCompressDebugSections(DebugCompressionType::DCT_ZlibGnu);
 
+  MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
+
   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
   std::unique_ptr<raw_fd_ostream> FDOS = getOutputStream(Opts, Diags, IsBinary);
   if (!FDOS)