libdw: Support DW_OP_addrx/constx and split DWARF addrx/constx support.

DW_OP_addrx/constx and GNU DebugFission DW_OP_GNU_addr/const_index take
as argument an index into the .debug_addr section for the associated CU.
This index gets resolved through dwarf_getlocation_attr. A new fake addr
CU is created per Dwarf for use with this new attribute. For split DWARF
files, the IDX_debug_addr gets replaced with the skeleton section and the
addr base is resolved immediately when constructing the split DWARF CU.
Move __libdw_cu_addr_base to libdwP.h to share with eu-readelf. Also
make it possible to resolve addrx[1234]/GNU_addr_index also as constant
indexes to (also) show when displaying these attributes in eu-readelf.

A new varlocs tests is added to test the resolving for both the DWARF4
and DWARF5 DW_OP variants. And now that addrx forms are resolved in
split DWARF files add the new DIEs with "single ranges" (those DIEs that
have a lowpc/highpc attribute pair) to run-all-dwarf-ranges.sh.

Signed-off-by: Mark Wielaard <mark@klomp.org>

2 files changed, 66 insertions, 7 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index e1872775..1a9f4a33 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2018-01-21  Mark Wielaard  <mark@klomp.org>
+
+	* readelf.c (get_indexed_addr): New function.
+	(print_ops): Handle DW_OP_addrx, DW_OP_GNU_addr_index,
+	DW_OP_constx, DW_OP_GNU_const_index separately and resolve
+	address.
+	(attr_callback): Print index and address for
+	DW_FORM_GNU_addr_index and DW_FORM_addrx[1234].
+
 2018-01-19  Mark Wielaard  <mark@klomp.org>
 
 	* readelf.c (options): Add info+.
diff --git a/src/readelf.c b/src/readelf.c
index 466d941e..18588022 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -4180,6 +4180,29 @@ print_bytes (size_t n, const unsigned char *bytes)
     }
 }
 
+static int
+get_indexed_addr (Dwarf_CU *cu, Dwarf_Word idx, Dwarf_Addr *addr)
+{
+  Elf_Data *debug_addr = cu->dbg->sectiondata[IDX_debug_addr];
+  if (debug_addr == NULL)
+    return -1;
+
+  Dwarf_Off base = __libdw_cu_addr_base (cu);
+  Dwarf_Word off = idx * cu->address_size;
+  if (base > debug_addr->d_size
+      || off > debug_addr->d_size - base
+      || cu->address_size > debug_addr->d_size - base - off)
+    return -1;
+
+  const unsigned char *addrp = debug_addr->d_buf + base + off;
+  if (cu->address_size == 4)
+    *addr = read_4ubyte_unaligned (cu->dbg, addrp);
+  else
+    *addr = read_8ubyte_unaligned (cu->dbg, addrp);
+
+  return 0;
+}
+
 static void
 print_ops (Dwfl_Module *dwflmod, Dwarf *dbg, int indent, int indentrest,
 	   unsigned int vers, unsigned int addrsize, unsigned int offset_size,
@@ -4348,19 +4371,36 @@ print_ops (Dwfl_Module *dwflmod, Dwarf *dbg, int indent, int indentrest,
 	case DW_OP_piece:
 	case DW_OP_regx:
 	case DW_OP_plus_uconst:
-	case DW_OP_constu:
+	case DW_OP_constu:;
+	  const unsigned char *start = data;
+	  uint64_t uleb;
+	  NEED (1);
+	  get_uleb128 (uleb, data, data + len);
+	  printf ("%*s[%2" PRIuMAX "] %s %" PRIu64 "\n",
+		  indent, "", (uintmax_t) offset, op_name, uleb);
+	  CONSUME (data - start);
+	  offset += 1 + (data - start);
+	  break;
+
 	case DW_OP_addrx:
 	case DW_OP_GNU_addr_index:
 	case DW_OP_constx:
 	case DW_OP_GNU_const_index:;
-	  const unsigned char *start = data;
-	  uint64_t uleb;
+	  start = data;
 	  NEED (1);
 	  get_uleb128 (uleb, data, data + len);
-	  printf ("%*s[%2" PRIuMAX "] %s %" PRIu64 "\n",
+	  printf ("%*s[%2" PRIuMAX "] %s [%" PRIu64 "] ",
 		  indent, "", (uintmax_t) offset, op_name, uleb);
 	  CONSUME (data - start);
 	  offset += 1 + (data - start);
+	  if (get_indexed_addr (cu, uleb, &addr) != 0)
+	    printf ("???\n");
+	  else
+	    {
+	      a = format_dwarf_addr (dwflmod, 0, addr, addr);
+	      printf ("%s\n", a);
+	      free (a);
+	    }
 	  break;
 
 	case DW_OP_bit_piece:
@@ -6148,9 +6188,19 @@ attr_callback (Dwarf_Attribute *attrp, void *arg)
 	    }
 	  char *a = format_dwarf_addr (cbargs->dwflmod, cbargs->addrsize,
 				       addr, addr);
-	  printf ("           %*s%-20s (%s) %s\n",
-		  (int) (level * 2), "", dwarf_attr_name (attr),
-		  dwarf_form_name (form), a);
+	  if (form != DW_FORM_addr )
+	    {
+	      Dwarf_Word index;
+	      if (dwarf_formudata (attrp, &index) != 0)
+		goto attrval_out;
+	      printf ("           %*s%-20s (%s) [%" PRIx64 "] %s\n",
+		      (int) (level * 2), "", dwarf_attr_name (attr),
+		      dwarf_form_name (form), index, a);
+	    }
+	  else
+	    printf ("           %*s%-20s (%s) %s\n",
+		    (int) (level * 2), "", dwarf_attr_name (attr),
+		    dwarf_form_name (form), a);
 	  free (a);
 	}
       break;