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[review v3] gdb: recognize new DWARF attributes: defaulted, deleted, calling conv.

From: "Tankut Baris Aktemur (Code Review)" <gerrit at gnutoolchain-gerrit dot osci dot io>
To: Andrew Burgess <andrew dot burgess at embecosm dot com>, gdb-patches at sourceware dot org
Cc: Tom Tromey <tromey at sourceware dot org>, Simon Marchi <simon dot marchi at polymtl dot ca>
Date: Thu, 31 Oct 2019 16:07:42 -0400
Subject: [review v3] gdb: recognize new DWARF attributes: defaulted, deleted, calling conv.
Auto-submitted: auto-generated
References: <gerrit.1571406803000.I54192f363115b78ec7435a8563b73fcace420765@gnutoolchain-gerrit.osci.io>
Reply-to: tankut dot baris dot aktemur at intel dot com, simon dot marchi at polymtl dot ca, tromey at sourceware dot org, andrew dot burgess at embecosm dot com, gdb-patches at sourceware dot org

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/135
......................................................................

gdb: recognize new DWARF attributes: defaulted, deleted, calling conv.

Extend GDB's internal representation of types to include the
DW_AT_calling_convention, DW_AT_defaulted, and DW_AT_deleted attributes
that were introduced in DWARF5.

These attributes will be helpful in a future patch about infcall'ing
functions with call-by-value parameters.  GDB will use the attributes
to decide whether the type of a call-by-value parameter is implicitly
pass-by-reference.

gdb/ChangeLog:
2019-10-31  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* dwarf2read.c (dwarf2_add_member_fn): Read the DW_AT_defaulted
	and DW_AT_deleted attributes of a function.
	(read_structure_type): Read the DW_AT_calling_convention attribute
	of a type.
	(is_valid_DW_AT_defaulted): New function.
	(is_valid_DW_AT_calling_convention_for_type): New function.
	* gdbtypes.h: Include dwarf2.h.
	(struct fn_field)<defaulted>: New field to store the
	DW_AT_defaulted attribute.
	(struct fn_field)<is_deleted>: New field to store the
	DW_AT_deleted attribute.
	(struct cplus_struct_type)<calling_convention>: New field to store
	the DW_AT_calling_convention attribute.
	(TYPE_FN_FIELD_DEFAULTED): New macro.
	(TYPE_FN_FIELD_DELETED): New macro.
	(TYPE_CPLUS_CALLING_CONVENTION): New macro.
	* gdbtypes.c (dump_fn_fieldlists): Update for the changes made
	to the .h file.
	(print_cplus_stuff): Likewise.

Change-Id: I54192f363115b78ec7435a8563b73fcace420765
---
M gdb/dwarf2read.c
M gdb/gdbtypes.c
M gdb/gdbtypes.h
3 files changed, 89 insertions(+), 1 deletion(-)



diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index cac719a..7fc3937 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -15436,6 +15436,25 @@
 	  && (type_name[len] == '\0' || type_name[len] == '<'));
 }
 
+/* Check if the given VALUE is a recognized enum
+   dwarf_defaulted_attribute constant according to DWARF5 spec,
+   Table 7.24.  */
+
+static bool
+is_valid_DW_AT_defaulted (ULONGEST value)
+{
+  switch (value)
+    {
+    case DW_DEFAULTED_no:
+    case DW_DEFAULTED_in_class:
+    case DW_DEFAULTED_out_of_class:
+      return true;
+    }
+
+  complaint (_("unrecognized DW_AT_defaulted value (%lu)"), value);
+  return false;
+}
+
 /* Add a member function to the proper fieldlist.  */
 
 static void
@@ -15548,6 +15567,16 @@
   if (attr && DW_UNSND (attr) != 0)
     fnp->is_artificial = 1;
 
+  /* Check for defaulted methods.  */
+  attr = dwarf2_attr (die, DW_AT_defaulted, cu);
+  if (attr != nullptr && is_valid_DW_AT_defaulted (DW_UNSND (attr)))
+    fnp->defaulted = (enum dwarf_defaulted_attribute) DW_UNSND (attr);
+
+  /* Check for deleted methods.  */
+  attr = dwarf2_attr (die, DW_AT_deleted, cu);
+  if (attr != nullptr && DW_UNSND (attr) != 0)
+    fnp->is_deleted = 1;
+
   fnp->is_constructor = dwarf2_is_constructor (die, cu);
 
   /* Get index in virtual function table if it is a virtual member
@@ -15787,6 +15816,26 @@
 	       objfile_name (cu->per_cu->dwarf2_per_objfile->objfile));
 }
 
+/* Check if the given VALUE is a valid enum dwarf_calling_convention
+   constant for a type, according to DWARF5 spec, Table 5.5.  */
+
+static bool
+is_valid_DW_AT_calling_convention_for_type (ULONGEST value)
+{
+  switch (value)
+    {
+    case DW_CC_normal:
+    case DW_CC_pass_by_reference:
+    case DW_CC_pass_by_value:
+      return true;
+
+    default:
+      complaint (_("unrecognized DW_AT_calling_convention value "
+		   "(%lu) for a type"), value);
+      return false;
+    }
+}
+
 /* Called when we find the DIE that starts a structure or union scope
    (definition) to create a type for the structure or union.  Fill in
    the type's name and general properties; the members will not be
@@ -15868,6 +15917,18 @@
   if (cu->language == language_cplus && die->tag == DW_TAG_class_type)
     TYPE_DECLARED_CLASS (type) = 1;
 
+  /* Store the calling convention in the type if it's available in
+     the die.  Otherwise the calling convention remains set to
+     the default value DW_CC_normal.  */
+  attr = dwarf2_attr (die, DW_AT_calling_convention, cu);
+  if (attr != nullptr
+      && is_valid_DW_AT_calling_convention_for_type (DW_UNSND (attr)))
+    {
+      ALLOCATE_CPLUS_STRUCT_TYPE (type);
+      TYPE_CPLUS_CALLING_CONVENTION (type)
+	= (enum dwarf_calling_convention) (DW_UNSND (attr));
+    }
+
   attr = dwarf2_attr (die, DW_AT_byte_size, cu);
   if (attr)
     {
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index fd1c765..d5448cf 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -4394,6 +4394,10 @@
 			    TYPE_FN_FIELD_PROTECTED (f, overload_idx));
 	  printfi_filtered (spaces + 8, "is_stub %d\n",
 			    TYPE_FN_FIELD_STUB (f, overload_idx));
+	  printfi_filtered (spaces + 8, "defaulted %d\n",
+			    TYPE_FN_FIELD_DEFAULTED (f, overload_idx));
+	  printfi_filtered (spaces + 8, "is_deleted %d\n",
+			    TYPE_FN_FIELD_DELETED (f, overload_idx));
 	  printfi_filtered (spaces + 8, "voffset %u\n",
 			    TYPE_FN_FIELD_VOFFSET (f, overload_idx));
 	}
@@ -4457,6 +4461,9 @@
     {
       dump_fn_fieldlists (type, spaces);
     }
+
+  printfi_filtered (spaces, "calling_convention %d\n",
+		    TYPE_CPLUS_CALLING_CONVENTION (type));
 }
 
 /* Print the contents of the TYPE's type_specific union, assuming that
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 6d6ff59..24628e7 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -50,6 +50,7 @@
 #include "gdbsupport/enum-flags.h"
 #include "gdbsupport/underlying.h"
 #include "gdbsupport/print-utils.h"
+#include "dwarf2.h"
 
 /* Forward declarations for prototypes.  */
 struct field;
@@ -940,9 +941,18 @@
 
   unsigned int is_constructor : 1;
 
+  /* * True if this function is deleted, false otherwise.  */
+
+  unsigned int is_deleted : 1;
+
+  /* * DW_AT_defaulted attribute for this function.  The value is one
+     of the DW_DEFAULTED constants.  */
+
+  ENUM_BITFIELD (dwarf_defaulted_attribute) defaulted : 2;
+
   /* * Unused.  */
 
-  unsigned int dummy:9;
+  unsigned int dummy:6;
 
   /* * Index into that baseclass's virtual function table, minus 2;
      else if static: VOFFSET_STATIC; else: 0.  */
@@ -1016,6 +1026,12 @@
 
     int is_dynamic : 2;
 
+    /* * The calling convention for this type, fetched from the
+       DW_AT_calling_convention attribute.  The value is one of the
+       DW_CC constants.  */
+
+    ENUM_BITFIELD (dwarf_calling_convention) calling_convention : 8;
+
     /* * The base class which defined the virtual function table pointer.  */
 
     struct type *vptr_basetype;
@@ -1414,6 +1430,8 @@
     ? (struct cplus_struct_type*)&cplus_struct_default \
     : TYPE_RAW_CPLUS_SPECIFIC(thistype))
 #define TYPE_RAW_CPLUS_SPECIFIC(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.cplus_stuff
+#define TYPE_CPLUS_CALLING_CONVENTION(thistype) \
+  TYPE_MAIN_TYPE(thistype)->type_specific.cplus_stuff->calling_convention
 #define TYPE_FLOATFORMAT(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.floatformat
 #define TYPE_GNAT_SPECIFIC(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.gnat_stuff
 #define TYPE_DESCRIPTIVE_TYPE(thistype) TYPE_GNAT_SPECIFIC(thistype)->descriptive_type
@@ -1530,6 +1548,8 @@
 #define TYPE_FN_FIELD_VOFFSET(thisfn, n) ((thisfn)[n].voffset-2)
 #define TYPE_FN_FIELD_VIRTUAL_P(thisfn, n) ((thisfn)[n].voffset > 1)
 #define TYPE_FN_FIELD_STATIC_P(thisfn, n) ((thisfn)[n].voffset == VOFFSET_STATIC)
+#define TYPE_FN_FIELD_DEFAULTED(thisfn, n) ((thisfn)[n].defaulted)
+#define TYPE_FN_FIELD_DELETED(thisfn, n) ((thisfn)[n].is_deleted)
 
 /* Accessors for typedefs defined by a class.  */
 #define TYPE_TYPEDEF_FIELD_ARRAY(thistype) \

-- 
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: I54192f363115b78ec7435a8563b73fcace420765
Gerrit-Change-Number: 135
Gerrit-PatchSet: 3
Gerrit-Owner: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Gerrit-Reviewer: Andrew Burgess <andrew.burgess@embecosm.com>
Gerrit-Reviewer: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Gerrit-CC: Simon Marchi <simon.marchi@polymtl.ca>
Gerrit-CC: Tom Tromey <tromey@sourceware.org>
Gerrit-MessageType: newpatchset

References:
- [review] gdb: recognize new DWARF attributes: defaulted, deleted, calling conv.
  - From: Tankut Baris Aktemur (Code Review)

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