diff options
Diffstat (limited to 'src/ortho/mcode/binary_file-memory.adb')
| -rw-r--r-- | src/ortho/mcode/binary_file-memory.adb | 47 |
1 files changed, 45 insertions, 2 deletions
diff --git a/src/ortho/mcode/binary_file-memory.adb b/src/ortho/mcode/binary_file-memory.adb index c9bb8ae2d..99789c602 100644 --- a/src/ortho/mcode/binary_file-memory.adb +++ b/src/ortho/mcode/binary_file-memory.adb @@ -21,17 +21,60 @@ package body Binary_File.Memory is -- Absolute section. Sect_Abs : Section_Acc; + -- PLT section (for x86-64). + Sect_Plt : Section_Acc; + procedure Set_Symbol_Address (Sym : Symbol; Addr : System.Address) is begin - Set_Symbol_Value (Sym, To_Pc_Type (Addr)); + if Arch = Arch_X86_64 and then Is_Symbol_Code (Sym) then + -- Branches are limited on x86-64 to a 32 bit offset. Create a + -- trampoline so that functions created outside of the module could + -- be reached using the standard ABI. + -- + -- This works only for code, not for data. Therefore we assume that + -- data symbols are correctly handled. + declare + V : Unsigned_64; + Pc : constant Pc_Type := Sect_Plt.Pc; + begin + Set_Current_Section (Sect_Plt); + Prealloc (16); + + -- Emit: movabs $ADDR, %r11 + V := Unsigned_64 (To_Pc_Type (Addr)); + Sect_Plt.Data (Pc + 0) := 16#49#; + Sect_Plt.Data (Pc + 1) := 16#BB#; + for I in Pc_Type range 0 .. 7 loop + Sect_Plt.Data (Pc + 2 + I) := Byte (V and 16#ff#); + V := Shift_Right (V, 8); + end loop; + + -- Emit: jmp *%r11 + Sect_Plt.Data (Pc + 10) := 16#41#; + Sect_Plt.Data (Pc + 11) := 16#FF#; + Sect_Plt.Data (Pc + 12) := 16#E3#; + + Sect_Plt.Pc := Pc + 13; + Set_Symbol_Value (Sym, Pc); + Set_Section (Sym, Sect_Plt); + end; + else + Set_Symbol_Value (Sym, To_Pc_Type (Addr)); + Set_Section (Sym, Sect_Abs); + end if; + + -- Symbol is not anymore undefined. Set_Scope (Sym, Sym_Global); - Set_Section (Sym, Sect_Abs); end Set_Symbol_Address; procedure Write_Memory_Init is begin Create_Section (Sect_Abs, "*ABS*", Section_Exec); Sect_Abs.Vaddr := 0; + + if Arch = Arch_X86_64 then + Create_Section (Sect_Plt, ".plt", Section_Exec); + end if; end Write_Memory_Init; procedure Write_Memory_Relocate (Error : out Boolean) |