diff mbox series

[Ada] Fix DWARF parsing for 32-bit targets on 64-bit hosts

Message ID 20220518084322.GA3361482@adacore.com
State New
Headers show
Series [Ada] Fix DWARF parsing for 32-bit targets on 64-bit hosts | expand

Commit Message

Pierre-Marie de Rodat May 18, 2022, 8:43 a.m. UTC 
Currently, a 64-bit gnatsymbolize fails to output line numbers and
accurate symbol names when run on 32-bit executables (and vice-versa).
This is because a couple of spots in System.Dwarf_Lines expect the
Address_Size found in the DWARF data to match the host Address'Size.

This patch corrects that assumption.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* libgnat/s-dwalin.adb (Aranges_Lookup, Enable_Cache): Adapt to
	changes in the signature of Read_Aranges_*.
	(Debug_Info_Lookup): Do not control address size read from
	DWARF.
	(Read_Aranges_Header): Do not control address size read from
	DWARF; return this size.
	(Read_Aranges_Entry): Use the size returned by
	Read_Aranges_Header.
diff mbox series

Patch

diff --git a/gcc/ada/libgnat/s-dwalin.adb b/gcc/ada/libgnat/s-dwalin.adb
--- a/gcc/ada/libgnat/s-dwalin.adb
+++ b/gcc/ada/libgnat/s-dwalin.adb
@@ -44,8 +44,6 @@  with System.Storage_Elements;  use System.Storage_Elements;
 
 package body System.Dwarf_Lines is
 
-   SSU : constant := System.Storage_Unit;
-
    function Get_Load_Displacement (C : Dwarf_Context) return Storage_Offset;
    --  Return the displacement between the load address present in the binary
    --  and the run-time address at which it is loaded (i.e. non-zero for PIE).
@@ -76,14 +74,16 @@  package body System.Dwarf_Lines is
    --  Read an entry format array, as specified by 6.2.4.1
 
    procedure Read_Aranges_Entry
-     (C     : in out Dwarf_Context;
-      Start :    out Address;
-      Len   :    out Storage_Count);
+     (C         : in out Dwarf_Context;
+      Addr_Size :        Natural;
+      Start     :    out Address;
+      Len       :    out Storage_Count);
    --  Read a single .debug_aranges pair
 
    procedure Read_Aranges_Header
      (C           : in out Dwarf_Context;
       Info_Offset :    out Offset;
+      Addr_Size   :    out Natural;
       Success     :    out Boolean);
    --  Read .debug_aranges header
 
@@ -1069,12 +1069,13 @@  package body System.Dwarf_Lines is
       Info_Offset :    out Offset;
       Success     :    out Boolean)
    is
+      Addr_Size : Natural;
    begin
       Info_Offset := 0;
       Seek (C.Aranges, 0);
 
       while Tell (C.Aranges) < Length (C.Aranges) loop
-         Read_Aranges_Header (C, Info_Offset, Success);
+         Read_Aranges_Header (C, Info_Offset, Addr_Size, Success);
          exit when not Success;
 
          loop
@@ -1082,7 +1083,7 @@  package body System.Dwarf_Lines is
                Start : Address;
                Len   : Storage_Count;
             begin
-               Read_Aranges_Entry (C, Start, Len);
+               Read_Aranges_Entry (C, Addr_Size, Start, Len);
                exit when Start = 0 and Len = 0;
                if Addr >= Start
                  and then Addr < Start + Len
@@ -1280,9 +1281,6 @@  package body System.Dwarf_Lines is
          Unit_Type := Read (C.Info);
 
          Addr_Sz := Read (C.Info);
-         if Addr_Sz /= (Address'Size / SSU) then
-            return;
-         end if;
 
          Read_Section_Offset (C.Info, Abbrev_Offset, Is64);
 
@@ -1290,9 +1288,6 @@  package body System.Dwarf_Lines is
          Read_Section_Offset (C.Info, Abbrev_Offset, Is64);
 
          Addr_Sz := Read (C.Info);
-         if Addr_Sz /= (Address'Size / SSU) then
-            return;
-         end if;
 
       else
          return;
@@ -1354,6 +1349,7 @@  package body System.Dwarf_Lines is
    procedure Read_Aranges_Header
      (C           : in out Dwarf_Context;
       Info_Offset :    out Offset;
+      Addr_Size   :    out Natural;
       Success     :    out Boolean)
    is
       Unit_Length : Offset;
@@ -1376,10 +1372,7 @@  package body System.Dwarf_Lines is
 
       --  Read address_size (ubyte)
 
-      Sz := Read (C.Aranges);
-      if Sz /= (Address'Size / SSU) then
-         return;
-      end if;
+      Addr_Size := Natural (uint8'(Read (C.Aranges)));
 
       --  Read segment_size (ubyte)
 
@@ -1392,7 +1385,7 @@  package body System.Dwarf_Lines is
 
       declare
          Cur_Off : constant Offset := Tell (C.Aranges);
-         Align   : constant Offset := 2 * Address'Size / SSU;
+         Align   : constant Offset := 2 * Offset (Addr_Size);
          Space   : constant Offset := Cur_Off mod Align;
       begin
          if Space /= 0 then
@@ -1408,14 +1401,15 @@  package body System.Dwarf_Lines is
    ------------------------
 
    procedure Read_Aranges_Entry
-     (C     : in out Dwarf_Context;
-      Start :    out Address;
-      Len   :    out Storage_Count)
+     (C         : in out Dwarf_Context;
+      Addr_Size :        Natural;
+      Start     :    out Address;
+      Len       :    out Storage_Count)
    is
    begin
       --  Read table
 
-      if Address'Size = 32 then
+      if Addr_Size = 4 then
          declare
             S, L : uint32;
          begin
@@ -1425,7 +1419,7 @@  package body System.Dwarf_Lines is
             Len   := Storage_Count (L);
          end;
 
-      elsif Address'Size = 64 then
+      elsif Addr_Size = 8 then
          declare
             S, L : uint64;
          begin
@@ -1520,6 +1514,7 @@  package body System.Dwarf_Lines is
       declare
          Info_Offset : Offset;
          Line_Offset : Offset;
+         Addr_Size   : Natural;
          Success     : Boolean;
          Ar_Start    : Address;
          Ar_Len      : Storage_Count;
@@ -1531,7 +1526,7 @@  package body System.Dwarf_Lines is
          Seek (C.Aranges, 0);
 
          while Tell (C.Aranges) < Length (C.Aranges) loop
-            Read_Aranges_Header (C, Info_Offset, Success);
+            Read_Aranges_Header (C, Info_Offset, Addr_Size, Success);
             exit when not Success;
 
             Debug_Info_Lookup (C, Info_Offset, Line_Offset, Success);
@@ -1540,7 +1535,7 @@  package body System.Dwarf_Lines is
             --  Read table
 
             loop
-               Read_Aranges_Entry (C, Ar_Start, Ar_Len);
+               Read_Aranges_Entry (C, Addr_Size, Ar_Start, Ar_Len);
                exit when Ar_Start = Null_Address and Ar_Len = 0;
 
                Len   := uint32 (Ar_Len);