[nvptx] Pass host specific ABI opts from mkoffload.

The patch adds an option -foffload-abi-host-opts, which
is set by host in TARGET_OFFLOAD_OPTIONS, and mkoffload then passes it's value
to host_compiler.

gcc/ChangeLog:
	* common.opt (foffload-abi-host-opts): New option.
	* config/aarch64/aarch64.cc (aarch64_offload_options): Set
	-foffload-abi-host-opts if -foffload-abi=lp64.
	* config/i386/i386-opts.cc (ix86_offload_options): Likewise.
	* config/rs6000/rs6000.cc (rs6000_offload_options): Likewise.
	* config/nvptx/mkoffload.cc (offload_abi_host_opts): Define.
	(compile_native): Append host_abi_opts to argv_obstack if
	offload_abi == OFFLOAD_ABI_LP64.
	* config/gcn/mkoffload.cc (offload_abi_host_opts): Define.
	(compile_native): Append host_abi_opts to argv_obstack if
	offload_abi == OFFLOAD_ABI_LP64.
	(main): Handle option -foffload-abi-host-opts.
	* lto-wrapper.cc (merge_and_complain): Handle
	-foffload-abi-host-opts.
	(append_compiler_options): Likewise.
	* opts.cc (common_handle_option): Likewise.

Signed-off-by: Prathamesh Kulkarni <prathameshk@nvidia.com>

diff --git a/gcc/common.opt b/gcc/common.opt
index ea39f87ae71..8e14787d2e8 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2361,6 +2361,10 @@ Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
 EnumValue
 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
 
+foffload-abi-host-opts=
+Common Driver Joined MissingArgError(option missing after %qs)
+-foffload-abi-host-opts=<options> Specify host ABI options.
+
 fomit-frame-pointer
 Common Var(flag_omit_frame_pointer) Optimization
 When possible do not generate stack frames.
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 6a3f1a23a9f..57198df8044 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -19002,7 +19002,7 @@ aarch64_offload_options (void)
   if (TARGET_ILP32)
     return xstrdup ("-foffload-abi=ilp32");
   else
-    return xstrdup ("-foffload-abi=lp64");
+    return xstrdup ("-foffload-abi=lp64 -foffload-abi-host-opts=-mabi=lp64");
 }
 
 static struct machine_function *
diff --git a/gcc/config/gcn/mkoffload.cc b/gcc/config/gcn/mkoffload.cc
index b8d981878ed..d608580a1e1 100644
--- a/gcc/config/gcn/mkoffload.cc
+++ b/gcc/config/gcn/mkoffload.cc
@@ -133,6 +133,8 @@ static const char *gcn_dumpbase;
 static struct obstack files_to_cleanup;
 
 enum offload_abi offload_abi = OFFLOAD_ABI_UNSET;
+const char *offload_abi_host_opts = NULL;
+
 uint32_t elf_arch = EF_AMDGPU_MACH_AMDGCN_GFX900;  // Default GPU architecture.
 uint32_t elf_flags = EF_AMDGPU_FEATURE_SRAMECC_UNSUPPORTED_V4;
 
@@ -819,16 +821,12 @@ compile_native (const char *infile, const char *outfile, const char *compiler,
   obstack_ptr_grow (&argv_obstack, gcn_dumpbase);
   obstack_ptr_grow (&argv_obstack, "-dumpbase-ext");
   obstack_ptr_grow (&argv_obstack, ".c");
-  switch (offload_abi)
+  if (offload_abi == OFFLOAD_ABI_LP64)
     {
-    case OFFLOAD_ABI_LP64:
-      obstack_ptr_grow (&argv_obstack, "-m64");
-      break;
-    case OFFLOAD_ABI_ILP32:
-      obstack_ptr_grow (&argv_obstack, "-m32");
-      break;
-    default:
-      gcc_unreachable ();
+      if (!offload_abi_host_opts)
+	fatal_error (input_location,
+		     "%<-foffload-abi-host-opts%> not specified.");
+      obstack_ptr_grow (&argv_obstack, offload_abi_host_opts);
     }
   obstack_ptr_grow (&argv_obstack, infile);
   obstack_ptr_grow (&argv_obstack, "-c");
@@ -998,6 +996,14 @@ main (int argc, char **argv)
 			 "unrecognizable argument of option %<" STR "%>");
 	}
 #undef STR
+      else if (startswith (argv[i], "-foffload-abi-host-opts="))
+	{
+	  if (offload_abi_host_opts)
+	    fatal_error (input_location,
+			 "-foffload-abi-host-opts specified multiple times");
+	  offload_abi_host_opts
+	    = argv[i] + strlen ("-foffload-abi-host-opts=");
+	}
       else if (strcmp (argv[i], "-fopenmp") == 0)
 	fopenmp = true;
       else if (strcmp (argv[i], "-fopenacc") == 0)
diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index f79257cc764..3c5443ab67f 100644
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -3680,7 +3680,7 @@ char *
 ix86_offload_options (void)
 {
   if (TARGET_LP64)
-    return xstrdup ("-foffload-abi=lp64");
+    return xstrdup ("-foffload-abi=lp64 -foffload-abi-host-opts=-m64");
   return xstrdup ("-foffload-abi=ilp32");
 }
 
diff --git a/gcc/config/nvptx/mkoffload.cc b/gcc/config/nvptx/mkoffload.cc
index 503b1abcefd..95ef54b85e9 100644
--- a/gcc/config/nvptx/mkoffload.cc
+++ b/gcc/config/nvptx/mkoffload.cc
@@ -61,6 +61,7 @@ static const char *omp_requires_file;
 static const char *ptx_dumpbase;
 
 enum offload_abi offload_abi = OFFLOAD_ABI_UNSET;
+const char *offload_abi_host_opts = NULL;
 
 /* Delete tempfiles.  */
 
@@ -607,16 +608,12 @@ compile_native (const char *infile, const char *outfile, const char *compiler,
   obstack_ptr_grow (&argv_obstack, ptx_dumpbase);
   obstack_ptr_grow (&argv_obstack, "-dumpbase-ext");
   obstack_ptr_grow (&argv_obstack, ".c");
-  switch (offload_abi)
+  if (offload_abi == OFFLOAD_ABI_LP64)
     {
-    case OFFLOAD_ABI_LP64:
-      obstack_ptr_grow (&argv_obstack, "-m64");
-      break;
-    case OFFLOAD_ABI_ILP32:
-      obstack_ptr_grow (&argv_obstack, "-m32");
-      break;
-    default:
-      gcc_unreachable ();
+      if (!offload_abi_host_opts)
+	fatal_error (input_location,
+		     "%<-foffload-abi-host-opts%> not specified.");
+      obstack_ptr_grow (&argv_obstack, offload_abi_host_opts);
     }
   obstack_ptr_grow (&argv_obstack, infile);
   obstack_ptr_grow (&argv_obstack, "-c");
@@ -721,6 +718,14 @@ main (int argc, char **argv)
 			 "unrecognizable argument of option " STR);
 	}
 #undef STR
+      else if (startswith (argv[i], "-foffload-abi-host-opts="))
+	{
+	  if (offload_abi_host_opts)
+	    fatal_error (input_location,
+			 "-foffload-abi-host-opts specified multiple times");
+	  offload_abi_host_opts
+	    = argv[i] + strlen ("-foffload-abi-host-opts=");
+	}
       else if (strcmp (argv[i], "-fopenmp") == 0)
 	fopenmp = true;
       else if (strcmp (argv[i], "-fopenacc") == 0)
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 08579bc83e6..fe03fd30fd7 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -17330,7 +17330,7 @@ static char *
 rs6000_offload_options (void)
 {
   if (TARGET_64BIT)
-    return xstrdup ("-foffload-abi=lp64");
+    return xstrdup ("-foffload-abi=lp64 -foffload-abi-host-opts=-m64");
   else
     return xstrdup ("-foffload-abi=ilp32");
 }
diff --git a/gcc/lto-wrapper.cc b/gcc/lto-wrapper.cc
index c07765b37a2..7de045da9b9 100644
--- a/gcc/lto-wrapper.cc
+++ b/gcc/lto-wrapper.cc
@@ -484,6 +484,7 @@ merge_and_complain (vec<cl_decoded_option> &decoded_options,
  
 
 	case OPT_foffload_abi_:
+	case OPT_foffload_abi_host_opts_:
 	  if (existing_opt == -1)
 	    decoded_options.safe_push (*foption);
 	  else if (foption->value != decoded_options[existing_opt].value)
@@ -745,6 +746,7 @@ append_compiler_options (obstack *argv_obstack, vec<cl_decoded_option> opts)
 	case OPT_fopenacc:
 	case OPT_fopenacc_dim_:
 	case OPT_foffload_abi_:
+	case OPT_foffload_abi_host_opts_:
 	case OPT_fcf_protection_:
 	case OPT_fasynchronous_unwind_tables:
 	case OPT_funwind_tables:
diff --git a/gcc/opts.cc b/gcc/opts.cc
index fc6abf6f582..c554e2fdd2c 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -3070,11 +3070,12 @@ common_handle_option (struct gcc_options *opts,
       break;
 
     case OPT_foffload_abi_:
+    case OPT_foffload_abi_host_opts_:
 #ifdef ACCEL_COMPILER
       /* Handled in the 'mkoffload's.  */
 #else
-      error_at (loc, "%<-foffload-abi%> option can be specified only for "
-		"offload compiler");
+      error_at (loc, "%qs option can be specified only for "
+		"offload compiler", arg);
 #endif
       break;