Re: [PATCH] d: Add darwin support for D language front-end

[Iain Buclaw <ibuclaw@gdcproject.org>]

Excerpts from Iain Sandoe's message of November 29, 2020 1:49 pm:
> Hi Iain
> 
> Iain Buclaw <ibuclaw@gdcproject.org> wrote:
> 
>> This patch adds necessary predefined version symbols and support for
>> moduleinfo sections for darwin to allow testing libphobos support.
>>
>> OK for mainline?
> 
> As we discussed off-list, this sets ABI (the section names are visible and  
> part
> of the contract with the runtime).
> 
> It’s highly desirable that we can interoperate with D objects built by  
> other impls.
> so the section naming convention should be agreed.
> 
> As far as I understand things, the names you have here agree with those used
> by “upstream” (but current the LLVM D variant uses something different).
> 
> The Darwin parts are OK, with a note to (re-)check on the section names  
> before
> the first release*.
> 
> thanks
> Iain
> 
> * perhaps it might be worth pinging the relevant upstream and LLV folks long
> before that - since the release cycles there mean that there will likely be  
> another
> one before GCC11 ships.
> 

I've sent Martin a message, so hoping for a response within the week
which name he'd prefer I go.  I suspect it'd be better to align with
LLVM instead of the reference DMD compiler.  As the compiler/run-time
integration of modules uses the same machinery, and we both want to
support loading shared DSOs (DMD is static only on OSX).

Adjusted the patch with some copy/paste fixes (missing tabs, Glibc gets
a mention).  Committed the following as r11-5522.

Regards,
Iain

---
gcc/ChangeLog:

	* config.gcc (*-*-darwin*): Set d_target_objs and target_has_targetdm.
	* config/elfos.h (TARGET_D_MINFO_SECTION): New macro.
	(TARGET_D_MINFO_START_NAME): New macro.
	(TARGET_D_MINFO_END_NAME): New macro.
	* config/t-darwin: Add darwin-d.o.
	* doc/tm.texi: Regenerate.
	* doc/tm.texi.in (D language and ABI): Add @hook for
	TARGET_D_MINFO_SECTION, TARGET_D_MINFO_START_NAME, and
	TARGET_D_MINFO_END_NAME.
	* config/darwin-d.c: New file.

gcc/d/ChangeLog:

	* d-target.def (d_minfo_section): New hook.
	(d_minfo_start_name): New hook.
	(d_minfo_end_name): New hook.
	* modules.cc: Include d-target.h.
	(register_moduleinfo): Update to use new targetdm hooks.
---
 gcc/config.gcc        |  2 ++
 gcc/config/darwin-d.c | 49 +++++++++++++++++++++++++++++++++++++++++++
 gcc/config/elfos.h    |  6 ++++++
 gcc/config/t-darwin   |  3 +++
 gcc/d/d-target.def    | 25 ++++++++++++++++++++++
 gcc/d/modules.cc      | 14 ++++++++++---
 gcc/doc/tm.texi       | 20 ++++++++++++++++++
 gcc/doc/tm.texi.in    |  6 ++++++
 8 files changed, 122 insertions(+), 3 deletions(-)
 create mode 100644 gcc/config/darwin-d.c

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 0ae58482657..aacab0d9133 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -702,8 +702,10 @@ case ${target} in
   extra_options="${extra_options} darwin.opt"
   c_target_objs="${c_target_objs} darwin-c.o"
   cxx_target_objs="${cxx_target_objs} darwin-c.o"
+  d_target_objs="${d_target_objs} darwin-d.o"
   fortran_target_objs="darwin-f.o"
   target_has_targetcm=yes
+  target_has_targetdm=yes
   extra_objs="${extra_objs} darwin.o"
   extra_gcc_objs="darwin-driver.o"
   default_use_cxa_atexit=yes
diff --git a/gcc/config/darwin-d.c b/gcc/config/darwin-d.c
new file mode 100644
index 00000000000..ced07ce006a
--- /dev/null
+++ b/gcc/config/darwin-d.c
@@ -0,0 +1,49 @@
+/* Darwin support needed only by D front-end.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm_d.h"
+#include "d/d-target.h"
+#include "d/d-target-def.h"
+
+/* Implement TARGET_D_OS_VERSIONS for Darwin targets.  */
+
+static void
+darwin_d_os_builtins (void)
+{
+  d_add_builtin_version ("Posix");
+  d_add_builtin_version ("OSX");
+  d_add_builtin_version ("darwin");
+}
+
+#undef TARGET_D_OS_VERSIONS
+#define TARGET_D_OS_VERSIONS darwin_d_os_builtins
+
+/* Define TARGET_D_MINFO_SECTION for Darwin targets.  */
+
+#undef TARGET_D_MINFO_SECTION
+#define TARGET_D_MINFO_SECTION "__DATA,__minfodata"
+
+#undef TARGET_D_MINFO_START_NAME
+#define TARGET_D_MINFO_START_NAME "*section$start$__DATA$__minfodata"
+
+#undef TARGET_D_MINFO_END_NAME
+#define TARGET_D_MINFO_END_NAME "*section$end$__DATA$__minfodata"
+
+struct gcc_targetdm targetdm = TARGETDM_INITIALIZER;
diff --git a/gcc/config/elfos.h b/gcc/config/elfos.h
index 74a3eafda6b..d8f169f54df 100644
--- a/gcc/config/elfos.h
+++ b/gcc/config/elfos.h
@@ -474,3 +474,9 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 
 #undef TARGET_LIBC_HAS_FUNCTION
 #define TARGET_LIBC_HAS_FUNCTION no_c99_libc_has_function
+
+/* ELF support needed only by D front-end.  */
+
+#define TARGET_D_MINFO_SECTION "minfo"
+#define TARGET_D_MINFO_START_NAME "__start_minfo"
+#define TARGET_D_MINFO_END_NAME "__stop_minfo"
diff --git a/gcc/config/t-darwin b/gcc/config/t-darwin
index 7f2ac282bfc..355389c60b4 100644
--- a/gcc/config/t-darwin
+++ b/gcc/config/t-darwin
@@ -26,6 +26,9 @@ darwin-c.o: $(srcdir)/config/darwin-c.c
 	$(COMPILE) $(PREPROCESSOR_DEFINES) $<
 	$(POSTCOMPILE)
 
+darwin-d.o: $(srcdir)/config/darwin-d.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
 
 darwin-f.o: $(srcdir)/config/darwin-f.c
 	$(COMPILE) $<
diff --git a/gcc/d/d-target.def b/gcc/d/d-target.def
index 41b31723188..728cba70335 100644
--- a/gcc/d/d-target.def
+++ b/gcc/d/d-target.def
@@ -46,5 +46,30 @@ relating to the target operating system.",
  void, (void),
  hook_void_void)
 
+/* ModuleInfo section name and brackets.  */
+DEFHOOKPOD
+(d_minfo_section,
+ "Contains the name of the section in which module info references should be\n\
+placed.  This section is expected to be bracketed by two symbols to indicate\n\
+the start and end address of the section, so that the runtime library can\n\
+collect all modules for each loaded shared library and executable.  The\n\
+default value of @code{NULL} disables the use of sections altogether.",
+ const char *, NULL)
+
+DEFHOOKPOD
+(d_minfo_start_name,
+ "If @code{TARGET_D_MINFO_SECTION} is defined, then this must also be defined\n\
+as the name of the symbol indicating the start address of the module info\n\
+section",
+ const char *, NULL)
+
+/* The name of the ModuleInfo section.  */
+DEFHOOKPOD
+(d_minfo_end_name,
+ "If @code{TARGET_D_MINFO_SECTION} is defined, then this must also be defined\n\
+as the name of the symbol indicating the end address of the module info\n\
+section",
+ const char *, NULL)
+
 /* Close the 'struct gcc_targetdm' definition.  */
 HOOK_VECTOR_END (C90_EMPTY_HACK)
diff --git a/gcc/d/modules.cc b/gcc/d/modules.cc
index 4b48c19a90e..742a24ff0bb 100644
--- a/gcc/d/modules.cc
+++ b/gcc/d/modules.cc
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "stringpool.h"
 
 #include "d-tree.h"
+#include "d-target.h"
 
 
 /* D generates module information to inform the runtime library which modules
@@ -405,6 +406,10 @@ build_dso_registry_var (const char * name, tree type)
 static void
 register_moduleinfo (Module *decl, tree minfo)
 {
+  /* No defined minfo section for target.  */
+  if (targetdm.d_minfo_section == NULL)
+    return;
+
   if (!targetm_common.have_named_sections)
     sorry ("%<-fmoduleinfo%> is not supported on this target");
 
@@ -420,7 +425,8 @@ register_moduleinfo (Module *decl, tree minfo)
   DECL_EXTERNAL (mref) = 0;
   DECL_PRESERVE_P (mref) = 1;
 
-  set_decl_section_name (mref, "minfo");
+  set_decl_section_name (mref, targetdm.d_minfo_section);
+  symtab_node::get (mref)->implicit_section = true;
   d_pushdecl (mref);
   rest_of_decl_compilation (mref, 1, 0);
 
@@ -431,10 +437,12 @@ register_moduleinfo (Module *decl, tree minfo)
   if (!first_module)
     return;
 
-  start_minfo_node = build_dso_registry_var ("__start_minfo", ptr_type_node);
+  start_minfo_node = build_dso_registry_var (targetdm.d_minfo_start_name,
+					     ptr_type_node);
   rest_of_decl_compilation (start_minfo_node, 1, 0);
 
-  stop_minfo_node = build_dso_registry_var ("__stop_minfo", ptr_type_node);
+  stop_minfo_node = build_dso_registry_var (targetdm.d_minfo_end_name,
+					    ptr_type_node);
   rest_of_decl_compilation (stop_minfo_node, 1, 0);
 
   /* Declare dso_slot and dso_initialized.  */
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index d9502c2c607..9f700b1c774 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -10822,6 +10822,26 @@ Similarly to @code{TARGET_D_CPU_VERSIONS}, but is used for versions
 relating to the target operating system.
 @end deftypefn
 
+@deftypevr {D Target Hook} {const char *} TARGET_D_MINFO_SECTION
+Contains the name of the section in which module info references should be
+placed.  This section is expected to be bracketed by two symbols to indicate
+the start and end address of the section, so that the runtime library can
+collect all modules for each loaded shared library and executable.  The
+default value of @code{NULL} disables the use of sections altogether.
+@end deftypevr
+
+@deftypevr {D Target Hook} {const char *} TARGET_D_MINFO_START_NAME
+If @code{TARGET_D_MINFO_SECTION} is defined, then this must also be defined
+as the name of the symbol indicating the start address of the module info
+section
+@end deftypevr
+
+@deftypevr {D Target Hook} {const char *} TARGET_D_MINFO_END_NAME
+If @code{TARGET_D_MINFO_SECTION} is defined, then this must also be defined
+as the name of the symbol indicating the end address of the module info
+section
+@end deftypevr
+
 @node Named Address Spaces
 @section Adding support for named address spaces
 @cindex named address spaces
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index b08923c8f28..012cb1c53f0 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -7353,6 +7353,12 @@ floating-point support; they are not included in this mechanism.
 
 @hook TARGET_D_OS_VERSIONS
 
+@hook TARGET_D_MINFO_SECTION
+
+@hook TARGET_D_MINFO_START_NAME
+
+@hook TARGET_D_MINFO_END_NAME
+
 @node Named Address Spaces
 @section Adding support for named address spaces
 @cindex named address spaces
-- 
2.27.0