readelf: print actual DW_OP_GNU_parameter_ref DIE offset.

DW_OP_GNU_parameter_ref takes as argument a CU relative offset to
a DW_TAG_formal_parameter DIE. Printing just that relative offset
makes it hard to find the actual DIE in the output. Now print the
actual DIE offset instead (unless -U is given). We already passed
around the base address of the CU. Now we pass around the actual
CU so we can use it to find both the base address and the CU offset.

Signed-off-by: Mark Wielaard <[email protected]>

1 files changed, 49 insertions, 32 deletions

diff --git a/src/readelf.c b/src/readelf.c
index 236d0887..d6208cbd 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -3749,7 +3749,7 @@ print_block (size_t n, const void *block)
 static void
 print_ops (Dwfl_Module *dwflmod, Dwarf *dbg, int indent, int indentrest,
 	   unsigned int vers, unsigned int addrsize, unsigned int offset_size,
-	   Dwarf_Word len, const unsigned char *data)
+	   struct Dwarf_CU *cu, Dwarf_Word len, const unsigned char *data)
 {
   const unsigned int ref_size = vers < 3 ? addrsize : offset_size;
 
@@ -4035,7 +4035,7 @@ print_ops (Dwfl_Module *dwflmod, Dwarf *dbg, int indent, int indentrest,
 		  indent, "", (uintmax_t) offset, op_name);
 	  NEED (uleb);
 	  print_ops (dwflmod, dbg, indent + 6, indent + 6, vers,
-		     addrsize, offset_size, uleb, data);
+		     addrsize, offset_size, cu, uleb, data);
 	  data += uleb;
 	  CONSUME (data - start);
 	  offset += 1 + (data - start);
@@ -4094,9 +4094,11 @@ print_ops (Dwfl_Module *dwflmod, Dwarf *dbg, int indent, int indentrest,
 	  /* 4 byte CU relative reference to the abstract optimized away
 	     DW_TAG_formal_parameter.  */
 	  NEED (4);
+	  uintmax_t param_off = (uintmax_t) read_4ubyte_unaligned (dbg, data);
+	  if (! print_unresolved_addresses && cu != NULL)
+	    param_off += cu->start;
 	  printf ("%*s[%4" PRIuMAX "] %s [%6" PRIxMAX "]\n",
-		  indent, "", (uintmax_t) offset, op_name,
-		  (uintmax_t) read_4ubyte_unaligned (dbg, data));
+		  indent, "", (uintmax_t) offset, op_name, param_off);
 	  CONSUME (4);
 	  data += 4;
 	  offset += 5;
@@ -4127,12 +4129,32 @@ struct listptr
   bool addr64:1;
   bool dwarf64:1;
   bool warned:1;
-  Dwarf_Addr base;
+  struct Dwarf_CU *cu;
 };
 
 #define listptr_offset_size(p)	((p)->dwarf64 ? 8 : 4)
 #define listptr_address_size(p)	((p)->addr64 ? 8 : 4)
 
+static Dwarf_Addr
+listptr_base (struct listptr *p)
+{
+  Dwarf_Addr base;
+  Dwarf_Die cu = CUDIE (p->cu);
+  /* Find the base address of the compilation unit.  It will normally
+     be specified by DW_AT_low_pc.  In DWARF-3 draft 4, the base
+     address could be overridden by DW_AT_entry_pc.  It's been
+     removed, but GCC emits DW_AT_entry_pc and not DW_AT_lowpc for
+     compilation units with discontinuous ranges.  */
+  if (unlikely (dwarf_lowpc (&cu, &base) != 0))
+    {
+      Dwarf_Attribute attr_mem;
+      if (dwarf_formaddr (dwarf_attr (&cu, DW_AT_entry_pc, &attr_mem),
+			  &base) != 0)
+	base = 0;
+    }
+  return base;
+}
+
 static int
 compare_listptr (const void *a, const void *b, void *arg)
 {
@@ -4161,7 +4183,7 @@ compare_listptr (const void *a, const void *b, void *arg)
 		 gettext ("%s %#" PRIx64 " used with different offset sizes"),
 		 name, (uint64_t) p1->offset);
 	}
-      if (p1->base != p2->base)
+      if (listptr_base (p1) != listptr_base (p2))
 	{
 	  p1->warned = p2->warned = true;
 	  error (0, 0,
@@ -4194,7 +4216,7 @@ reset_listptr (struct listptr_table *table)
 static void
 notice_listptr (enum section_e section, struct listptr_table *table,
 		uint_fast8_t address_size, uint_fast8_t offset_size,
-		Dwarf_Addr base, Dwarf_Off offset)
+		struct Dwarf_CU *cu, Dwarf_Off offset)
 {
   if (print_debug_sections & section)
     {
@@ -4215,7 +4237,7 @@ notice_listptr (enum section_e section, struct listptr_table *table,
 	  .addr64 = address_size == 8,
 	  .dwarf64 = offset_size == 8,
 	  .offset = offset,
-	  .base = base
+	  .cu = cu
 	};
       assert (p->offset == offset);
     }
@@ -4232,7 +4254,7 @@ sort_listptr (struct listptr_table *table, const char *name)
 static bool
 skip_listptr_hole (struct listptr_table *table, size_t *idxp,
 		   uint_fast8_t *address_sizep, uint_fast8_t *offset_sizep,
-		   Dwarf_Addr *base, ptrdiff_t offset,
+		   Dwarf_Addr *base, struct Dwarf_CU **cu, ptrdiff_t offset,
 		   unsigned char **readp, unsigned char *endp)
 {
   if (table->n == 0)
@@ -4265,7 +4287,9 @@ skip_listptr_hole (struct listptr_table *table, size_t *idxp,
   if (offset_sizep != NULL)
     *offset_sizep = listptr_offset_size (p);
   if (base != NULL)
-    *base = p->base;
+    *base = listptr_base (p);
+  if (cu != NULL)
+    *cu = p->cu;
 
   return false;
 }
@@ -4594,7 +4618,7 @@ print_debug_ranges_section (Dwfl_Module *dwflmod,
       ptrdiff_t offset = readp - (unsigned char *) data->d_buf;
 
       if (first && skip_listptr_hole (&known_rangelistptr, &listptr_idx,
-				      &address_size, NULL, &base,
+				      &address_size, NULL, &base, NULL,
 				      offset, &readp, endp))
 	continue;
 
@@ -4796,7 +4820,8 @@ print_cfa_program (const unsigned char *readp, const unsigned char *const endp,
 	    // XXX overflow check
 	    get_uleb128 (op1, readp);	/* Length of DW_FORM_block.  */
 	    printf ("     def_cfa_expression %" PRIu64 "\n", op1);
-	    print_ops (dwflmod, dbg, 10, 10, version, ptr_size, 0, op1, readp);
+	    print_ops (dwflmod, dbg, 10, 10, version, ptr_size, 0, NULL,
+		       op1, readp);
 	    readp += op1;
 	    break;
 	  case DW_CFA_expression:
@@ -4805,7 +4830,8 @@ print_cfa_program (const unsigned char *readp, const unsigned char *const endp,
 	    get_uleb128 (op2, readp);	/* Length of DW_FORM_block.  */
 	    printf ("     expression r%" PRIu64 " (%s) \n",
 		    op1, regname (op1));
-	    print_ops (dwflmod, dbg, 10, 10, version, ptr_size, 0, op2, readp);
+	    print_ops (dwflmod, dbg, 10, 10, version, ptr_size, 0, NULL,
+		       op2, readp);
 	    readp += op2;
 	    break;
 	  case DW_CFA_offset_extended_sf:
@@ -4848,7 +4874,8 @@ print_cfa_program (const unsigned char *readp, const unsigned char *const endp,
 	    get_uleb128 (op2, readp);	/* Length of DW_FORM_block.  */
 	    printf ("     val_expression r%" PRIu64 " (%s)\n",
 		    op1, regname (op1));
-	    print_ops (dwflmod, dbg, 10, 10, version, ptr_size, 0, op2, readp);
+	    print_ops (dwflmod, dbg, 10, 10, version, ptr_size, 0,
+		       NULL, op2, readp);
 	    readp += op2;
 	    break;
 	  case DW_CFA_MIPS_advance_loc8:
@@ -5423,7 +5450,7 @@ struct attrcb_args
   unsigned int version;
   unsigned int addrsize;
   unsigned int offset_size;
-  Dwarf_Addr cu_base;
+  struct Dwarf_CU *cu;
 };
 
 
@@ -5558,7 +5585,7 @@ attr_callback (Dwarf_Attribute *attrp, void *arg)
 	case DW_AT_GNU_call_site_target_clobbered:
 	  notice_listptr (section_loc, &known_loclistptr,
 			  cbargs->addrsize, cbargs->offset_size,
-			  cbargs->cu_base, num);
+			  cbargs->cu, num);
 	  if (!cbargs->silent)
 	    printf ("           %*s%-20s (%s) location list [%6" PRIxMAX "]\n",
 		    (int) (level * 2), "", dwarf_attr_name (attr),
@@ -5568,7 +5595,7 @@ attr_callback (Dwarf_Attribute *attrp, void *arg)
 	case DW_AT_ranges:
 	  notice_listptr (section_ranges, &known_rangelistptr,
 			  cbargs->addrsize, cbargs->offset_size,
-			  cbargs->cu_base, num);
+			  cbargs->cu, num);
 	  if (!cbargs->silent)
 	    printf ("           %*s%-20s (%s) range list [%6" PRIxMAX "]\n",
 		    (int) (level * 2), "", dwarf_attr_name (attr),
@@ -5707,7 +5734,7 @@ attr_callback (Dwarf_Attribute *attrp, void *arg)
 	  print_ops (cbargs->dwflmod, cbargs->dbg,
 		     12 + level * 2, 12 + level * 2,
 		     cbargs->version, cbargs->addrsize, cbargs->offset_size,
-		     block.length, block.data);
+		     attrp->cu, block.length, block.data);
 	  break;
 	}
       break;
@@ -5806,18 +5833,7 @@ print_debug_units (Dwfl_Module *dwflmod,
       goto do_return;
     }
 
-  /* Find the base address of the compilation unit.  It will
-     normally be specified by DW_AT_low_pc.  In DWARF-3 draft 4,
-     the base address could be overridden by DW_AT_entry_pc.  It's
-     been removed, but GCC emits DW_AT_entry_pc and not DW_AT_lowpc
-     for compilation units with discontinuous ranges.  */
-  if (unlikely (dwarf_lowpc (&dies[0], &args.cu_base) != 0))
-    {
-      Dwarf_Attribute attr_mem;
-      if (dwarf_formaddr (dwarf_attr (&dies[0], DW_AT_entry_pc, &attr_mem),
-			  &args.cu_base) != 0)
-	args.cu_base = 0;
-    }
+  args.cu = dies[0].cu;
 
   do
     {
@@ -6509,6 +6525,7 @@ print_debug_loc_section (Dwfl_Module *dwflmod,
   uint_fast8_t offset_size = 4;
 
   bool first = true;
+  struct Dwarf_CU *cu = NULL;
   Dwarf_Addr base = 0;
   unsigned char *readp = data->d_buf;
   unsigned char *const endp = (unsigned char *) data->d_buf + data->d_size;
@@ -6518,7 +6535,7 @@ print_debug_loc_section (Dwfl_Module *dwflmod,
 
       if (first && skip_listptr_hole (&known_loclistptr, &listptr_idx,
 				      &address_size, &offset_size, &base,
-				      offset, &readp, endp))
+				      &cu, offset, &readp, endp))
 	continue;
 
       if (unlikely (data->d_size - offset < address_size * 2))
@@ -6580,7 +6597,7 @@ print_debug_loc_section (Dwfl_Module *dwflmod,
 	    }
 
 	  print_ops (dwflmod, dbg, 1, 18 + (address_size * 4),
-		     3 /*XXX*/, address_size, offset_size, len, readp);
+		     3 /*XXX*/, address_size, offset_size, cu, len, readp);
 
 	  first = false;
 	  readp += len;