Handle multiple addresses in call_site_target

A large customer program has a function that is partitioned into hot
and cold parts.  A variable in a callee of this function is described
using DW_OP_GNU_entry_value, but gdb gets confused when trying to find
the caller.  I tracked this down to dwarf2_get_pc_bounds interpreting
the function's changes so that the returned low PC is the "wrong"
function.

Intead, when processing DW_TAG_call_site, the low PC of each range in
DW_AT_ranges should be preserved in the call_site_target.  This fixes
the variable lookup in the test case I have.

I didn't write a standalone test for this as it seemed excessively
complicated.

2 files changed, 47 insertions, 0 deletions

diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
index 37e5a16..5cfd5a2 100644
--- a/gdb/dwarf2/loc.c
+++ b/gdb/dwarf2/loc.c
@@ -726,6 +726,18 @@ call_site_target::iterate_over_addresses
       }
       break;
 
+    case call_site_target::ADDRESSES:
+      {
+	dwarf2_per_objfile *per_objfile = call_site->per_objfile;
+	compunit_symtab *cust = per_objfile->get_symtab (call_site->per_cu);
+	int sect_idx = cust->block_line_section ();
+	CORE_ADDR delta = per_objfile->objfile->section_offsets[sect_idx];
+
+	for (unsigned i = 0; i < m_loc.addresses.length; ++i)
+	  callback (m_loc.addresses.values[i] + delta);
+      }
+      break;
+
     default:
       internal_error (__FILE__, __LINE__, _("invalid call site target kind"));
     }
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index f9c942d..6c41ede 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -13311,6 +13311,11 @@ read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
   cu->get_builder ()->set_local_using_directives (cstk.local_using_directives);
 }
 
+static void dwarf2_ranges_read_low_addrs (unsigned offset,
+					  struct dwarf2_cu *cu,
+					  dwarf_tag tag,
+					  std::vector<CORE_ADDR> &result);
+
 /* Read in DW_TAG_call_site and insert it to CU->call_site_htab.  */
 
 static void
@@ -13474,6 +13479,10 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
 
       target_die = follow_die_ref (die, attr, &target_cu);
       gdb_assert (target_cu->per_objfile->objfile == objfile);
+
+      struct attribute *ranges_attr
+	= dwarf2_attr (target_die, DW_AT_ranges, target_cu);
+
       if (die_is_declaration (target_die, target_cu))
 	{
 	  const char *target_physname;
@@ -13489,6 +13498,18 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
 	  else
 	    call_site->target.set_loc_physname (target_physname);
 	}
+      else if (ranges_attr != nullptr && ranges_attr->form_is_unsigned ())
+	{
+	  ULONGEST ranges_offset = (ranges_attr->as_unsigned ()
+				    + target_cu->gnu_ranges_base);
+	  std::vector<CORE_ADDR> addresses;
+	  dwarf2_ranges_read_low_addrs (ranges_offset, target_cu,
+					target_die->tag, addresses);
+	  CORE_ADDR *saved = XOBNEWVAR (&objfile->objfile_obstack, CORE_ADDR,
+					addresses.size ());
+	  std::copy (addresses.begin (), addresses.end (), saved);
+	  call_site->target.set_loc_array (addresses.size (), saved);
+	}
       else
 	{
 	  CORE_ADDR lowpc;
@@ -14062,6 +14083,20 @@ dwarf2_ranges_read (unsigned offset, CORE_ADDR *low_return,
   return 1;
 }
 
+/* Process ranges and fill in a vector of the low PC values only.  */
+
+static void
+dwarf2_ranges_read_low_addrs (unsigned offset, struct dwarf2_cu *cu,
+			      dwarf_tag tag,
+			      std::vector<CORE_ADDR> &result)
+{
+  dwarf2_ranges_process (offset, cu, tag,
+			 [&] (CORE_ADDR start, CORE_ADDR end)
+    {
+      result.push_back (start);
+    });
+}
+
 /* Get low and high pc attributes from a die.  See enum pc_bounds_kind
    definition for the return value.  *LOWPC and *HIGHPC are set iff
    neither PC_BOUNDS_NOT_PRESENT nor PC_BOUNDS_INVALID are returned.  */