gdb: move call site types to call-site.h

I hesitated between putting  the file in the dwarf2 directory (as
gdb/dwarf2/call-site.h) or in the common directory (as gdb/call-site.h).
The concept of call site is not DWARF-specific, another debug info
reader could provide this information.  But as it is, the implementation
is a bit DWARF-specific, as one form it can take is a DWARF expression
and parameters can be defined using a DWARF register number.  So I ended up
choosing to put it under dwarf2/.  If another debug info reader ever
wants to provide call site information, we can introduce a layer of
abstraction between the "common" call site and the "dwarf2" call site.

The copyright start year comes from the date `struct call_site` was
introduced.

Change-Id: I1cd84aa581fbbf729edc91b20f7d7a6e0377014d
Reviewed-By: Bruno Larsen <blarsen@redhat.com>

1 files changed, 244 insertions, 0 deletions

diff --git a/gdb/dwarf2/call-site.h b/gdb/dwarf2/call-site.h
new file mode 100644
index 0000000..f5bee967
--- /dev/null
+++ b/gdb/dwarf2/call-site.h
@@ -0,0 +1,244 @@
+/* Call site information.
+
+   Copyright (C) 2011-2022 Free Software Foundation, Inc.
+
+   Contributed by Cygnus Support, using pieces from other GDB modules.
+
+   This file is part of GDB.
+
+   This program 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 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef CALL_SITE_H
+#define CALL_SITE_H
+
+#include "dwarf2/types.h"
+#include "gdbsupport/function-view.h"
+#include "frame-info.h"
+
+struct dwarf2_locexpr_baton;
+struct dwarf2_per_cu_data;
+struct dwarf2_per_objfile;
+
+/* struct call_site_parameter can be referenced in callees by several ways.  */
+
+enum call_site_parameter_kind
+{
+  /* * Use field call_site_parameter.u.dwarf_reg.  */
+  CALL_SITE_PARAMETER_DWARF_REG,
+
+  /* * Use field call_site_parameter.u.fb_offset.  */
+  CALL_SITE_PARAMETER_FB_OFFSET,
+
+  /* * Use field call_site_parameter.u.param_offset.  */
+  CALL_SITE_PARAMETER_PARAM_OFFSET
+};
+
+struct call_site_target
+{
+  /* The kind of location held by this call site target.  */
+  enum kind
+  {
+    /* An address.  */
+    PHYSADDR,
+    /* A name.  */
+    PHYSNAME,
+    /* A DWARF block.  */
+    DWARF_BLOCK,
+    /* An array of addresses.  */
+    ADDRESSES,
+  };
+
+  void set_loc_physaddr (CORE_ADDR physaddr)
+  {
+    m_loc_kind = PHYSADDR;
+    m_loc.physaddr = physaddr;
+  }
+
+  void set_loc_physname (const char *physname)
+    {
+      m_loc_kind = PHYSNAME;
+      m_loc.physname = physname;
+    }
+
+  void set_loc_dwarf_block (dwarf2_locexpr_baton *dwarf_block)
+    {
+      m_loc_kind = DWARF_BLOCK;
+      m_loc.dwarf_block = dwarf_block;
+    }
+
+  void set_loc_array (unsigned length, const CORE_ADDR *data)
+  {
+    m_loc_kind = ADDRESSES;
+    m_loc.addresses.length = length;
+    m_loc.addresses.values = data;
+  }
+
+  /* Callback type for iterate_over_addresses.  */
+
+  using iterate_ftype = gdb::function_view<void (CORE_ADDR)>;
+
+  /* Call CALLBACK for each DW_TAG_call_site's DW_AT_call_target
+     address.  CALLER_FRAME (for registers) can be NULL if it is not
+     known.  This function always may throw NO_ENTRY_VALUE_ERROR.  */
+
+  void iterate_over_addresses (struct gdbarch *call_site_gdbarch,
+			       const struct call_site *call_site,
+			       frame_info_ptr caller_frame,
+			       iterate_ftype callback) const;
+
+private:
+
+  union
+  {
+    /* Address.  */
+    CORE_ADDR physaddr;
+    /* Mangled name.  */
+    const char *physname;
+    /* DWARF block.  */
+    struct dwarf2_locexpr_baton *dwarf_block;
+    /* Array of addresses.  */
+    struct
+    {
+      unsigned length;
+      const CORE_ADDR *values;
+    } addresses;
+  } m_loc;
+
+  /* * Discriminant for union field_location.  */
+  enum kind m_loc_kind;
+};
+
+union call_site_parameter_u
+{
+  /* * DW_TAG_formal_parameter's DW_AT_location's DW_OP_regX
+     as DWARF register number, for register passed
+     parameters.  */
+
+  int dwarf_reg;
+
+  /* * Offset from the callee's frame base, for stack passed
+     parameters.  This equals offset from the caller's stack
+     pointer.  */
+
+  CORE_ADDR fb_offset;
+
+  /* * Offset relative to the start of this PER_CU to
+     DW_TAG_formal_parameter which is referenced by both
+     caller and the callee.  */
+
+  cu_offset param_cu_off;
+};
+
+struct call_site_parameter
+{
+  ENUM_BITFIELD (call_site_parameter_kind) kind : 2;
+
+  union call_site_parameter_u u;
+
+  /* * DW_TAG_formal_parameter's DW_AT_call_value.  It is never NULL.  */
+
+  const gdb_byte *value;
+  size_t value_size;
+
+  /* * DW_TAG_formal_parameter's DW_AT_call_data_value.
+     It may be NULL if not provided by DWARF.  */
+
+  const gdb_byte *data_value;
+  size_t data_value_size;
+};
+
+/* * A place where a function gets called from, represented by
+   DW_TAG_call_site.  It can be looked up from symtab->call_site_htab.  */
+
+struct call_site
+{
+  call_site (CORE_ADDR pc, dwarf2_per_cu_data *per_cu,
+	     dwarf2_per_objfile *per_objfile)
+    : per_cu (per_cu), per_objfile (per_objfile), m_unrelocated_pc (pc)
+  {}
+
+  static int
+  eq (const call_site *a, const call_site *b)
+  {
+    return a->m_unrelocated_pc == b->m_unrelocated_pc;
+  }
+
+  static hashval_t
+  hash (const call_site *a)
+  {
+    return a->m_unrelocated_pc;
+  }
+
+  static int
+  eq (const void *a, const void *b)
+  {
+    return eq ((const call_site *)a, (const call_site *)b);
+  }
+
+  static hashval_t
+  hash (const void *a)
+  {
+    return hash ((const call_site *)a);
+  }
+
+  /* Return the address of the first instruction after this call.  */
+
+  CORE_ADDR pc () const;
+
+  /* Call CALLBACK for each target address.  CALLER_FRAME (for
+     registers) can be NULL if it is not known.  This function may
+     throw NO_ENTRY_VALUE_ERROR.  */
+
+  void iterate_over_addresses (struct gdbarch *call_site_gdbarch,
+			       frame_info_ptr caller_frame,
+			       call_site_target::iterate_ftype callback)
+    const
+  {
+    return target.iterate_over_addresses (call_site_gdbarch, this,
+					  caller_frame, callback);
+  }
+
+  /* * List successor with head in FUNC_TYPE.TAIL_CALL_LIST.  */
+
+  struct call_site *tail_call_next = nullptr;
+
+  /* * Describe DW_AT_call_target.  Missing attribute uses
+     FIELD_LOC_KIND_DWARF_BLOCK with FIELD_DWARF_BLOCK == NULL.  */
+
+  struct call_site_target target {};
+
+  /* * Size of the PARAMETER array.  */
+
+  unsigned parameter_count = 0;
+
+  /* * CU of the function where the call is located.  It gets used
+     for DWARF blocks execution in the parameter array below.  */
+
+  dwarf2_per_cu_data *const per_cu = nullptr;
+
+  /* objfile of the function where the call is located.  */
+
+  dwarf2_per_objfile *const per_objfile = nullptr;
+
+private:
+  /* Unrelocated address of the first instruction after this call.  */
+  const CORE_ADDR m_unrelocated_pc;
+
+public:
+  /* * Describe DW_TAG_call_site's DW_TAG_formal_parameter.  */
+
+  struct call_site_parameter parameter[];
+};
+
+#endif /* CALL_SITE_H */