arm64-hide-symbols-for-stricter-binutils

    AArch64 GOT fixed

Gbp-Pq: Name 0011-arm64-hide-symbols-for-stricter-binutils.patch

diff --git a/Changes b/Changes
index cc59f635ebb9a35f9958f3330e9ac9abc0d9bcaa..4c0eac7a7a1056ecc0c33efbd1da0969a886b8f0 100644 (file)
--- a/Changes
+++ b/Changes
@@ -135,6 +135,10 @@ OCaml 4.05.0 (13 Jul 2017):
   (Hannes Mehnert, Guillaume Bury,
    review by Daniel Bünzli, Gabriel Scherer, Damien Doligez)
 
+- GPR#1330: when generating dynamically-linkable code on AArch64, always
+  reference symbols (even locally-defined ones) through the GOT.
+  (Mark Shinwell, review by Xavier Leroy)
+
 ### Standard library:
 
 - MPR#6975, GPR#902: Truncate function added to stdlib Buffer module

diff --git a/asmcomp/arm64/emit.mlp b/asmcomp/arm64/emit.mlp
index f75646e123dd6e0414f281d4e8067911bca6abf8..729096c576331972fa362035d5aaa4a15030d3b1 100644 (file)
--- a/asmcomp/arm64/emit.mlp
+++ b/asmcomp/arm64/emit.mlp
@@ -114,6 +114,7 @@ let emit_addressing addr r =
   | Iindexed ofs ->
       `[{emit_reg r}, #{emit_int ofs}]`
   | Ibased(s, ofs) ->
+      assert (not !Clflags.dlcode);  (* see selection.ml *)
       `[{emit_reg r}, #:lo12:{emit_symbol_offset s ofs}]`
 
 (* Record live pointers at call points *)
@@ -323,7 +324,7 @@ let emit_literals() =
 (* Emit code to load the address of a symbol *)
 
 let emit_load_symbol_addr dst s =
-  if (not !Clflags.dlcode) || Compilenv.symbol_in_current_unit s then begin
+  if not !Clflags.dlcode then begin
     `  adrp    {emit_reg dst}, {emit_symbol s}\n`;
     `  add     {emit_reg dst}, {emit_reg dst}, #:lo12:{emit_symbol s}\n`
   end else begin
@@ -609,6 +610,7 @@ let emit_instr i =
           match addr with
           | Iindexed _ -> i.arg.(0)
           | Ibased(s, ofs) ->
+              assert (not !Clflags.dlcode);  (* see selection.ml *)
               `        adrp    {emit_reg reg_tmp1}, {emit_symbol_offset s ofs}\n`;
               reg_tmp1 in
         begin match size with
@@ -636,6 +638,7 @@ let emit_instr i =
           match addr with
           | Iindexed _ -> i.arg.(1)
           | Ibased(s, ofs) ->
+              assert (not !Clflags.dlcode);
               `        adrp    {emit_reg reg_tmp1}, {emit_symbol_offset s ofs}\n`;
               reg_tmp1 in
         begin match size with
@@ -924,7 +927,15 @@ let fundecl fundecl =
 
 let emit_item = function
   | Cglobal_symbol s -> `      .globl  {emit_symbol s}\n`;
-  | Cdefine_symbol s -> `{emit_symbol s}:\n`
+  | Cdefine_symbol s ->
+    if !Clflags.dlcode then begin
+      (* GOT relocations against non-global symbols don't seem to work
+         properly: GOT entries are not created for the symbols and the
+         relocations evaluate to random other GOT entries.  For the moment
+         force all symbols to be global. *)
+      `        .globl  {emit_symbol s}\n`;
+    end;
+    `{emit_symbol s}:\n`
   | Cint8 n -> `       .byte   {emit_int n}\n`
   | Cint16 n -> `      .short  {emit_int n}\n`
   | Cint32 n -> `      .long   {emit_nativeint n}\n`

diff --git a/asmcomp/arm64/selection.ml b/asmcomp/arm64/selection.ml
index d8ea7f83bf8a392ad215d3517bcd54a36e967bf6..b714d0032cf59b552fefd2df0db175959c44e923 100644 (file)
--- a/asmcomp/arm64/selection.ml
+++ b/asmcomp/arm64/selection.ml
@@ -82,8 +82,8 @@ let inline_ops =
   [ "sqrt"; "caml_bswap16_direct"; "caml_int32_direct_bswap";
     "caml_int64_direct_bswap"; "caml_nativeint_direct_bswap" ]
 
-let use_direct_addressing symb =
-  (not !Clflags.dlcode) || Compilenv.symbol_in_current_unit symb
+let use_direct_addressing _symb =
+  not !Clflags.dlcode
 
 (* Instruction selection *)