[PATCH v2 6/6] aarch64: Add DLL import/export to AArch64 target

[Evgeny Karpov <Evgeny.Karpov@microsoft.com>]

This patch reuses the MinGW implementation to enable DLL import/export
functionality for the aarch64-w64-mingw32 target. It also modifies
environment configurations for MinGW.

gcc/ChangeLog:

	* config.gcc: Add winnt-dll.o, which contains the DLL
	import/export implementation.
	* config/aarch64/aarch64.cc (aarch64_legitimize_pe_coff_symbol):
	Add a conditional function that reuses the MinGW implementation
	for COFF and does nothing otherwise.
	(aarch64_load_symref_appropriately): Add dllimport
	implementation.
	(aarch64_expand_call): Likewise.
	(aarch64_legitimize_address): Likewise.
	* config/aarch64/cygming.h (SYMBOL_FLAG_DLLIMPORT): Modify MinGW
	environment to support DLL import/export.
	(SYMBOL_FLAG_DLLEXPORT): Likewise.
	(SYMBOL_REF_DLLIMPORT_P): Likewise.
	(SYMBOL_FLAG_STUBVAR): Likewise.
	(SYMBOL_REF_STUBVAR_P): Likewise.
	(TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): Likewise.
	(TARGET_ASM_FILE_END): Likewise.
	(SUB_TARGET_RECORD_STUB): Likewise.
	(GOT_ALIAS_SET): Likewise.
	(PE_COFF_EXTERN_DECL_SHOULD_BE_LEGITIMIZED): Likewise.
	(HAVE_64BIT_POINTERS): Likewise.
---
 gcc/config.gcc                |  4 +++-
 gcc/config/aarch64/aarch64.cc | 37 +++++++++++++++++++++++++++++++++++
 gcc/config/aarch64/cygming.h  | 26 ++++++++++++++++++++++--
 3 files changed, 64 insertions(+), 3 deletions(-)

diff --git a/gcc/config.gcc b/gcc/config.gcc
index d053b98efa8..331285b7b6d 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -1276,10 +1276,12 @@ aarch64-*-mingw*)
 	tm_file="${tm_file} mingw/mingw32.h"
 	tm_file="${tm_file} mingw/mingw-stdint.h"
 	tm_file="${tm_file} mingw/winnt.h"
+	tm_file="${tm_file} mingw/winnt-dll.h"
 	tmake_file="${tmake_file} aarch64/t-aarch64"
 	target_gtfiles="$target_gtfiles \$(srcdir)/config/mingw/winnt.cc"
+	target_gtfiles="$target_gtfiles \$(srcdir)/config/mingw/winnt-dll.cc"
 	extra_options="${extra_options} mingw/cygming.opt mingw/mingw.opt"
-	extra_objs="${extra_objs} winnt.o"
+	extra_objs="${extra_objs} winnt.o winnt-dll.o"
 	c_target_objs="${c_target_objs} msformat-c.o"
 	d_target_objs="${d_target_objs} winnt-d.o"
 	tmake_file="${tmake_file} mingw/t-cygming"
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 3418e57218f..5706b9aeb6b 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -860,6 +860,10 @@ static const attribute_spec aarch64_gnu_attributes[] =
   { "Advanced SIMD type", 1, 1, false, true,  false, true,  NULL, NULL },
   { "SVE type",		  3, 3, false, true,  false, true,  NULL, NULL },
   { "SVE sizeless type",  0, 0, false, true,  false, true,  NULL, NULL },
+#if TARGET_DLLIMPORT_DECL_ATTRIBUTES
+  { "dllimport", 0, 0, false, false, false, false, handle_dll_attribute, NULL },
+  { "dllexport", 0, 0, false, false, false, false, handle_dll_attribute, NULL },
+#endif
 #ifdef SUBTARGET_ATTRIBUTE_TABLE
   SUBTARGET_ATTRIBUTE_TABLE
 #endif
@@ -2819,6 +2823,15 @@ tls_symbolic_operand_type (rtx addr)
   return tls_kind;
 }
 
+rtx aarch64_legitimize_pe_coff_symbol (rtx addr, bool inreg)
+{
+#if TARGET_PECOFF
+  return legitimize_pe_coff_symbol (addr, inreg);
+#else
+  return NULL_RTX;
+#endif
+}
+
 /* We'll allow lo_sum's in addresses in our legitimate addresses
    so that combine would take care of combining addresses where
    necessary, but for generation purposes, we'll generate the address
@@ -2865,6 +2878,17 @@ static void
 aarch64_load_symref_appropriately (rtx dest, rtx imm,
 				   enum aarch64_symbol_type type)
 {
+  /* If legitimize returns a value
+     copy it directly to the destination and return.  */
+
+  rtx tmp = aarch64_legitimize_pe_coff_symbol (imm, true);
+
+  if (tmp)
+    {
+       emit_insn (gen_rtx_SET (dest, tmp));
+       return;
+    }
+
   switch (type)
     {
     case SYMBOL_SMALL_ABSOLUTE:
@@ -11233,6 +11257,12 @@ aarch64_expand_call (rtx result, rtx mem, rtx cookie, bool sibcall)
 
   gcc_assert (MEM_P (mem));
   callee = XEXP (mem, 0);
+
+  tmp = aarch64_legitimize_pe_coff_symbol (callee, false);
+
+  if (tmp)
+    callee = tmp;
+
   mode = GET_MODE (callee);
   gcc_assert (mode == Pmode);
 
@@ -12709,6 +12739,13 @@ aarch64_anchor_offset (HOST_WIDE_INT offset, HOST_WIDE_INT size,
 static rtx
 aarch64_legitimize_address (rtx x, rtx /* orig_x  */, machine_mode mode)
 {
+  if (TARGET_DLLIMPORT_DECL_ATTRIBUTES)
+    {
+      rtx tmp = aarch64_legitimize_pe_coff_symbol (x, true);
+      if (tmp)
+	return tmp;
+    }
+
   /* Try to split X+CONST into Y=X+(CONST & ~mask), Y+(CONST&mask),
      where mask is selected by alignment and size of the offset.
      We try to pick as large a range for the offset as possible to
diff --git a/gcc/config/aarch64/cygming.h b/gcc/config/aarch64/cygming.h
index 76623153080..e26488735db 100644
--- a/gcc/config/aarch64/cygming.h
+++ b/gcc/config/aarch64/cygming.h
@@ -28,12 +28,18 @@ along with GCC; see the file COPYING3.  If not see
 
 #define print_reg(rtx, code, file) (gcc_unreachable ())
 
-#define SYMBOL_FLAG_DLLIMPORT 0
-#define SYMBOL_FLAG_DLLEXPORT 0
+#define SYMBOL_FLAG_DLLIMPORT		(SYMBOL_FLAG_MACH_DEP << 0)
+#define SYMBOL_REF_DLLIMPORT_P(X) \
+	((SYMBOL_REF_FLAGS (X) & SYMBOL_FLAG_DLLIMPORT) != 0)
 
+#define SYMBOL_FLAG_DLLEXPORT		(SYMBOL_FLAG_MACH_DEP << 1)
 #define SYMBOL_REF_DLLEXPORT_P(X) \
 	((SYMBOL_REF_FLAGS (X) & SYMBOL_FLAG_DLLEXPORT) != 0)
 
+#define SYMBOL_FLAG_STUBVAR	(SYMBOL_FLAG_MACH_DEP << 2)
+#define SYMBOL_REF_STUBVAR_P(X) \
+	((SYMBOL_REF_FLAGS (X) & SYMBOL_FLAG_STUBVAR) != 0)
+
 /* Disable SEH and declare the required SEH-related macros that are
 still needed for compilation.  */
 #undef TARGET_SEH
@@ -59,6 +65,12 @@ still needed for compilation.  */
 #define TARGET_ASM_UNIQUE_SECTION mingw_pe_unique_section
 #define TARGET_ENCODE_SECTION_INFO  mingw_pe_encode_section_info
 
+#define TARGET_VALID_DLLIMPORT_ATTRIBUTE_P mingw_pe_valid_dllimport_attribute_p
+
+/* Output function declarations at the end of the file.  */
+#undef TARGET_ASM_FILE_END
+#define TARGET_ASM_FILE_END mingw_pe_file_end
+
 /* Declare the type properly for any external libcall.  */
 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN) \
   mingw_pe_declare_function_type (FILE, XSTR (FUN, 0), 1)
@@ -158,6 +170,9 @@ still needed for compilation.  */
   { "selectany", 0, 0, true, false, false, false, \
     mingw_handle_selectany_attribute, NULL }
 
+#undef SUB_TARGET_RECORD_STUB
+#define SUB_TARGET_RECORD_STUB mingw_pe_record_stub
+
 #define SUPPORTS_ONE_ONLY 1
 
 /* Define this to be nonzero if static stack checking is supported.  */
@@ -168,4 +183,11 @@ still needed for compilation.  */
 #undef MAX_OFILE_ALIGNMENT
 #define MAX_OFILE_ALIGNMENT (8192 * 8)
 
+#undef GOT_ALIAS_SET
+#define GOT_ALIAS_SET mingw_GOT_alias_set ()
+
+#define PE_COFF_EXTERN_DECL_SHOULD_BE_LEGITIMIZED 1
+
+#define HAVE_64BIT_POINTERS 1
+
 #endif
-- 
2.25.1