Support for dllimport and dllexport attributes for i386-pe.

	* tree.h (DECL_NON_ADDR_CONST_P): New accessor macro.
	(struct tree_decl): Add non_addr_const_p field.
	* tree.c (staticp): Use.
	* i386/cygwin32.h (CPP_PREDEFINES): Map __declspec(x) to GCC
	attributes.
	(SUBTARGET_SWITCHES): Switches to turn on/off dllimport|export
	attributes. Also accept -mwindows option.
	(VALID_MACHINE_DECL_ATTRIBUTE): New macro.
	(MERGE_MACHINE_DECL_ATTRIBUTE): New macro.
	(REDO_SECTION_INFO_P): New macro.
	(DRECTVE_SECTION_FUNCTION): New macro.
	(drectve_section): Cover function to implement above.
	(SWITCH_TO_SECTION_FUNCTION): New macro.
	(switch_to_section): Covert function to implement above.
	(EXTRA_SECTIONS): Add in_drectve.
	(EXTRA_SECTION_FUNCTIONS): Add in_drectve and switch_to_section.
	(ENCODE_SECTION_INFO): Delete old macro and redefine as a function.
	(STRIP_NAME_ENCODING): Handle new attributes.
	(ASM_OUTPUT_LABELREF): New macro.
	(ASM_OUTPUT_FUNCTION_NAME): New macro.
	(ASM_OUTPUT_COMMON): New macro.
	(ASM_OUTPUT_DECLARE_OBJECT_NAME): New macro.
	* i386/mingw32.h (CPP_PREDEFINES): Map __declspec(x) to GCC
	attributes.
	* i386/winnt.c (i386_pe_valid_decl_attribute_p): New function.
	(i386_pe_merge_decl_attributes): New function.
	(i386_pe_check_vtable_importexport): New function.
	(i386_pe_dllexport_p): New function.
	(i386_pe_dllimport_p): New function.
	(i386_pe_dllexport_name_p): New function.
	(i386_pe_dllimport_name_p): New function.
	(i386_pe_mark_dllexport): New function.
	(i386_pe_mark_dllimport): New function.
	(i386_pe_encode_section_info): New function.
	(i386_pe_unique_section): Strip encoding from name first.

From-SVN: r20983

1 files changed, 400 insertions, 0 deletions

diff --git a/gcc/config/i386/winnt.c b/gcc/config/i386/winnt.c
index 2f4cc88..95daf14 100644
--- a/gcc/config/i386/winnt.c
+++ b/gcc/config/i386/winnt.c
@@ -28,6 +28,351 @@ Boston, MA 02111-1307, USA.  */
 #include "tree.h"
 #include "flags.h"
 
+/* i386/PE specific attribute support.
+
+   i386/PE has two new attributes:
+   dllexport - for exporting a function/variable that will live in a dll
+   dllimport - for importing a function/variable from a dll
+
+   Microsoft allows multiple declspecs in one __declspec, separating
+   them with spaces.  We do NOT support this.  Instead, use __declspec
+   multiple times.
+*/
+
+/* Return nonzero if ATTR is a valid attribute for DECL.
+   ATTRIBUTES are any existing attributes and ARGS are the arguments
+   supplied with ATTR.  */
+
+int
+i386_pe_valid_decl_attribute_p (decl, attributes, attr, args)
+     tree decl;
+     tree attributes;
+     tree attr;
+     tree args;
+{
+  if (args != NULL_TREE)
+    return 0;
+
+  if (is_attribute_p ("dllexport", attr))
+    return 1;
+  if (is_attribute_p ("dllimport", attr))
+    return 1;
+
+  return i386_valid_decl_attribute_p (decl, attributes, attr, args);
+}
+
+/* Merge attributes in decls OLD and NEW.
+
+   This handles the following situation:
+
+   __declspec (dllimport) int foo;
+   int foo;
+
+   The second instance of `foo' nullifies the dllimport.  */
+
+tree
+i386_pe_merge_decl_attributes (old, new)
+     tree old, new;
+{
+  tree a;
+  int delete_dllimport_p;
+
+  old = DECL_MACHINE_ATTRIBUTES (old);
+  new = DECL_MACHINE_ATTRIBUTES (new);
+
+  /* What we need to do here is remove from `old' dllimport if it doesn't
+     appear in `new'.  dllimport behaves like extern: if a declaration is
+     marked dllimport and a definition appears later, then the object
+     is not dllimport'd.  */
+
+  if (lookup_attribute ("dllimport", old) != NULL_TREE
+      && lookup_attribute ("dllimport", new) == NULL_TREE)
+    delete_dllimport_p = 1;
+  else
+    delete_dllimport_p = 0;
+
+  a = merge_attributes (old, new);
+
+  if (delete_dllimport_p)
+    {
+      tree prev,t;
+
+      /* Scan the list for dllimport and delete it.  */
+      for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
+	{
+	  if (is_attribute_p ("dllimport", TREE_PURPOSE (t)))
+	    {
+	      if (prev == NULL_TREE)
+		a = TREE_CHAIN (a);
+	      else
+		TREE_CHAIN (prev) = TREE_CHAIN (t);
+	      break;
+	    }
+	}
+    }
+
+  return a;
+}
+
+/* Check a type that has a virtual table, and see if any virtual methods are
+   marked for import or export, and if so, arrange for the vtable to
+   be imported or exported.  */
+
+static int
+i386_pe_check_vtable_importexport (type)
+     tree type;
+{
+  tree methods = TYPE_METHODS (type);
+  tree fndecl;
+
+  if (TREE_CODE (methods) == FUNCTION_DECL)
+    fndecl = methods;
+  else if (TREE_VEC_ELT (methods, 0) != NULL_TREE)
+    fndecl = TREE_VEC_ELT (methods, 0);
+  else
+    fndecl = TREE_VEC_ELT (methods, 1);
+
+  while (fndecl)
+    {
+      if (DECL_VIRTUAL_P (fndecl) || DECL_VINDEX (fndecl) != NULL_TREE)
+	{
+	  tree exp = lookup_attribute ("dllimport",
+				       DECL_MACHINE_ATTRIBUTES (fndecl));
+	  if (exp == 0)
+	    exp = lookup_attribute ("dllexport",
+				    DECL_MACHINE_ATTRIBUTES (fndecl));
+	  if (exp)
+	    return 1;
+	}
+
+      fndecl = TREE_CHAIN (fndecl);
+    }
+
+  return 0;
+}
+
+/* Return non-zero if DECL is a dllexport'd object.  */
+
+#if 0
+tree current_class_type; /* FIXME */
+#endif
+
+int
+i386_pe_dllexport_p (decl)
+     tree decl;
+{
+  tree exp;
+
+  if (TREE_CODE (decl) != VAR_DECL
+      && TREE_CODE (decl) != FUNCTION_DECL)
+    return 0;
+  exp = lookup_attribute ("dllexport", DECL_MACHINE_ATTRIBUTES (decl));
+  if (exp)
+    return 1;
+
+#if 0 /* This was a hack to get vtable's exported or imported since only one
+	 copy of them is ever output.  Disabled pending better solution.  */
+  /* For C++, the vtables might have to be marked.  */
+  if (TREE_CODE (decl) == VAR_DECL && DECL_VIRTUAL_P (decl))
+    {
+      if (TREE_PUBLIC (decl)
+	  && DECL_EXTERNAL (decl) == 0
+	  && (DECL_CONTEXT (decl)
+	      ? i386_pe_check_vtable_importexport (DECL_CONTEXT (decl))
+	      : current_class_type
+	      ? i386_pe_check_vtable_importexport (current_class_type)
+	      : 0)
+	  )
+	return 1;
+    }
+#endif
+
+  return 0;
+}
+
+/* Return non-zero if DECL is a dllimport'd object.  */
+
+int
+i386_pe_dllimport_p (decl)
+     tree decl;
+{
+  tree imp;
+
+  if (TREE_CODE (decl) == FUNCTION_DECL
+      && TARGET_NOP_FUN_DLLIMPORT)
+    return 0;
+
+  if (TREE_CODE (decl) != VAR_DECL
+      && TREE_CODE (decl) != FUNCTION_DECL)
+    return 0;
+  imp = lookup_attribute ("dllimport", DECL_MACHINE_ATTRIBUTES (decl));
+  if (imp)
+    return 1;
+
+#if 0 /* This was a hack to get vtable's exported or imported since only one
+	 copy of them is ever output.  Disabled pending better solution.  */
+  /* For C++, the vtables might have to be marked.  */
+  if (TREE_CODE (decl) == VAR_DECL && DECL_VIRTUAL_P (decl))
+    {
+      if (TREE_PUBLIC (decl)
+	  && DECL_EXTERNAL (decl)
+	  && (DECL_CONTEXT (decl)
+	      ? i386_pe_check_vtable_importexport (DECL_CONTEXT (decl))
+	      : current_class_type
+	      ? i386_pe_check_vtable_importexport (current_class_type)
+	      : 0)
+	  )
+	return 1;
+    }
+#endif
+
+  return 0;
+}
+
+/* Return non-zero if SYMBOL is marked as being dllexport'd.  */
+
+int
+i386_pe_dllexport_name_p (symbol)
+     char *symbol;
+{
+  return symbol[0] == '@' && symbol[1] == 'e' && symbol[2] == '.';
+}
+
+/* Return non-zero if SYMBOL is marked as being dllimport'd.  */
+
+int
+i386_pe_dllimport_name_p (symbol)
+     char *symbol;
+{
+  return symbol[0] == '@' && symbol[1] == 'i' && symbol[2] == '.';
+}
+
+/* Mark a DECL as being dllexport'd.
+   Note that we override the previous setting (eg: dllimport).  */
+
+void
+i386_pe_mark_dllexport (decl)
+     tree decl;
+{
+  char *oldname, *newname;
+  rtx rtlname;
+  tree idp;
+
+  rtlname = XEXP (DECL_RTL (decl), 0);
+  if (GET_CODE (rtlname) == SYMBOL_REF)
+    oldname = XSTR (rtlname, 0);
+  else if (GET_CODE (rtlname) == MEM
+	   && GET_CODE (XEXP (rtlname, 0)) == SYMBOL_REF)
+    oldname = XSTR (XEXP (rtlname, 0), 0);
+  else
+    abort ();
+  if (i386_pe_dllimport_name_p (oldname))
+    oldname += 9;
+  else if (i386_pe_dllexport_name_p (oldname))
+    return; /* already done */
+
+  newname = alloca (strlen (oldname) + 4);
+  sprintf (newname, "@e.%s", oldname);
+
+  /* We pass newname through get_identifier to ensure it has a unique
+     address.  RTL processing can sometimes peek inside the symbol ref
+     and compare the string's addresses to see if two symbols are
+     identical.  */
+  idp = get_identifier (newname);
+
+  XEXP (DECL_RTL (decl), 0) =
+    gen_rtx (SYMBOL_REF, Pmode, IDENTIFIER_POINTER (idp));
+}
+
+/* Mark a DECL as being dllimport'd.  */
+
+void
+i386_pe_mark_dllimport (decl)
+     tree decl;
+{
+  char *oldname, *newname;
+  tree idp;
+  rtx rtlname, newrtl;
+
+  rtlname = XEXP (DECL_RTL (decl), 0);
+  if (GET_CODE (rtlname) == SYMBOL_REF)
+    oldname = XSTR (rtlname, 0);
+  else if (GET_CODE (rtlname) == MEM
+	   && GET_CODE (XEXP (rtlname, 0)) == SYMBOL_REF)
+    oldname = XSTR (XEXP (rtlname, 0), 0);
+  else
+    abort ();
+  if (i386_pe_dllexport_name_p (oldname))
+    {
+      error ("`%s' declared as both exported to and imported from a DLL.",
+             IDENTIFIER_POINTER (DECL_NAME (decl)));
+      return;
+    }
+  else if (i386_pe_dllimport_name_p (oldname))
+    {
+      /* Already done, but force correct linkage since the redeclaration 
+         might have omitted explicit extern.  Sigh.  */
+      if (TREE_CODE (decl) == VAR_DECL
+	  /* ??? Is this test for vtables needed?  */
+	  && !DECL_VIRTUAL_P (decl))
+	{
+	  DECL_EXTERNAL (decl) = 1;
+	  TREE_PUBLIC (decl) = 1;
+	}
+      return;
+    }
+
+  /* ??? One can well ask why we're making these checks here,
+     and that would be a good question.  */
+
+  /* Imported variables can't be initialized. Note that C++ classes
+     are marked initial, so we need to check.  */
+  if (TREE_CODE (decl) == VAR_DECL
+      && !DECL_VIRTUAL_P (decl)
+      && (DECL_INITIAL (decl)
+          && ! TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl))))
+    {
+      error_with_decl (decl, "initialized variable `%s' is marked dllimport");
+      return;
+    }
+  /* Nor can they be static.  */
+  if (TREE_CODE (decl) == VAR_DECL
+      /* ??? Is this test for vtables needed?  */
+      && !DECL_VIRTUAL_P (decl)
+      && 0 /*???*/)
+    {
+      error_with_decl (decl, "static variable `%s' is marked dllimport");
+      return;
+    }
+
+  /* `extern' needn't be specified with dllimport.
+     Specify `extern' now and hope for the best.  Sigh.  */
+  if (TREE_CODE (decl) == VAR_DECL
+      /* ??? Is this test for vtables needed?  */
+      && !DECL_VIRTUAL_P (decl))
+    {
+      DECL_EXTERNAL (decl) = 1;
+      TREE_PUBLIC (decl) = 1;
+    }
+
+  newname = alloca (strlen (oldname) + 11);
+  sprintf (newname, "@i._imp__%s", oldname);
+
+  /* We pass newname through get_identifier to ensure it has a unique
+     address.  RTL processing can sometimes peek inside the symbol ref
+     and compare the string's addresses to see if two symbols are
+     identical.  */
+  idp = get_identifier (newname);
+
+  newrtl = gen_rtx (MEM, Pmode,
+		    gen_rtx (SYMBOL_REF, Pmode,
+			     IDENTIFIER_POINTER (idp)));
+  XEXP (DECL_RTL (decl), 0) = newrtl;
+
+  /* Can't treat a pointer to this as a constant address */
+  DECL_NON_ADDR_CONST_P (decl) = 1;
+}
+
 /* Return string which is the former assembler name modified with a 
    suffix consisting of an atsign (@) followed by the number of bytes of 
    arguments */
@@ -66,6 +411,59 @@ gen_stdcall_suffix (decl)
   return IDENTIFIER_POINTER (get_identifier (newsym));
 }
 
+/* Cover function to implement ENCODE_SECTION_INFO.  */
+
+void
+i386_pe_encode_section_info (decl)
+     tree decl;
+{
+  /* This bit is copied from i386.h.  */
+  if (optimize > 0 && TREE_CONSTANT (decl)
+      && (!flag_writable_strings || TREE_CODE (decl) != STRING_CST))
+    {
+      rtx rtl = (TREE_CODE_CLASS (TREE_CODE (decl)) != 'd'
+                 ? TREE_CST_RTL (decl) : DECL_RTL (decl));
+      SYMBOL_REF_FLAG (XEXP (rtl, 0)) = 1;
+    }
+
+  if (TREE_CODE (decl) == FUNCTION_DECL)
+    if (lookup_attribute ("stdcall",
+			  TYPE_ATTRIBUTES (TREE_TYPE (decl))))
+      XEXP (DECL_RTL (decl), 0) = 
+	gen_rtx (SYMBOL_REF, Pmode, gen_stdcall_suffix (decl));
+
+  /* Mark the decl so we can tell from the rtl whether the object is
+     dllexport'd or dllimport'd.  */
+
+  if (i386_pe_dllexport_p (decl))
+    i386_pe_mark_dllexport (decl);
+  else if (i386_pe_dllimport_p (decl))
+    i386_pe_mark_dllimport (decl);
+  /* It might be that DECL has already been marked as dllimport, but a
+     subsequent definition nullified that.  The attribute is gone but
+     DECL_RTL still has @i._imp__foo.  We need to remove that. Ditto
+     for the DECL_NON_ADDR_CONST_P flag.  */
+  else if ((TREE_CODE (decl) == FUNCTION_DECL
+	    || TREE_CODE (decl) == VAR_DECL)
+	   && DECL_RTL (decl) != NULL_RTX
+	   && GET_CODE (DECL_RTL (decl)) == MEM
+	   && GET_CODE (XEXP (DECL_RTL (decl), 0)) == MEM
+	   && GET_CODE (XEXP (XEXP (DECL_RTL (decl), 0), 0)) == SYMBOL_REF
+	   && i386_pe_dllimport_name_p (XSTR (XEXP (XEXP (DECL_RTL (decl), 0), 0), 0)))
+    {
+      char *oldname = XSTR (XEXP (XEXP (DECL_RTL (decl), 0), 0), 0);
+      tree idp = get_identifier (oldname + 9);
+      rtx newrtl = gen_rtx (SYMBOL_REF, Pmode, IDENTIFIER_POINTER (idp));
+
+      XEXP (DECL_RTL (decl), 0) = newrtl;
+
+      DECL_NON_ADDR_CONST_P (decl) = 0;
+
+      /* We previously set TREE_PUBLIC and DECL_EXTERNAL.
+	 We leave these alone for now.  */
+    }
+}
+
 /* Cover function for UNIQUE_SECTION.  */
 
 void
@@ -77,6 +475,8 @@ i386_pe_unique_section (decl, reloc)
   char *name,*string,*prefix;
 
   name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
+  /* Strip off any encoding in fnname.  */
+  STRIP_NAME_ENCODING (name, name);
 
   /* The object is put in, for example, section .text$foo.
      The linker will then ultimately place them in .text