From 69ae63d4b02b15d47ab90a4bf96880329601f116 Mon Sep 17 00:00:00 2001
From: Graydon Hoare <graydon@mozilla.com>
Date: Tue, 12 Oct 2010 16:51:27 -0700
Subject: Fix horribly embarassing signedness bug in backend, plus related
 regressions.

---
 src/boot/be/asm.ml   |  5 +++--
 src/boot/be/il.ml    |  6 ++++++
 src/boot/be/x86.ml   |  5 ++++-
 src/boot/me/trans.ml | 12 +++++++++---
 4 files changed, 22 insertions(+), 6 deletions(-)

(limited to 'src')

diff --git a/src/boot/be/asm.ml b/src/boot/be/asm.ml
index 4b05e347..939b297c 100644
--- a/src/boot/be/asm.ml
+++ b/src/boot/be/asm.ml
@@ -590,8 +590,9 @@ and lower_frag
       | WORD (m,e) ->
           iflog sess
             (fun _ ->
-               log sess "lowering word %s"
-                 (string_of_ty_mach m));
+               log sess "lowering word %s with val %s"
+                 (string_of_ty_mach m)
+                 (fmt_to_str fmt_frag frag));
           word (bytes_of_ty_mach m) (mach_is_signed m) e
 
       | ALIGN_FILE (n, frag) ->
diff --git a/src/boot/be/il.ml b/src/boot/be/il.ml
index 0888f8e8..9a63576e 100644
--- a/src/boot/be/il.ml
+++ b/src/boot/be/il.ml
@@ -812,6 +812,12 @@ let umov (dst:cell) (src:operand) : quad' =
     else unary UMOV dst src
 ;;
 
+let imov (dst:cell) (src:operand) : quad' =
+    if (cell_is_nil dst || operand_is_nil src)
+    then Dead
+    else unary IMOV dst src
+;;
+
 let zero (dst:cell) (count:operand) : quad' =
   unary ZERO dst count
 ;;
diff --git a/src/boot/be/x86.ml b/src/boot/be/x86.ml
index d2d70ea2..c9b13d04 100644
--- a/src/boot/be/x86.ml
+++ b/src/boot/be/x86.ml
@@ -663,6 +663,7 @@ let emit_c_call
 
   let emit = Il.emit e in
   let mov dst src = emit (Il.umov dst src) in
+  let imov dst src = emit (Il.imov dst src) in
   let binary op dst imm = emit (Il.binary op dst (c dst) (immi imm)) in
 
   (* rust calls get task as arg0  *)
@@ -702,6 +703,8 @@ let emit_c_call
                         mov (r tmp1) arg;
                         mov (word_n (h esp) i) (c (r tmp1));
                 end
+            | Il.Imm (_, tm) when mach_is_signed tm ->
+                imov (word_n (h esp) i) arg
             | _ ->
                 mov (word_n (h esp) i) arg
       end
@@ -2151,7 +2154,7 @@ let mov (signed:bool) (dst:Il.cell) (src:Il.operand) : Asm.frag =
 
     (* rm32 <- imm32 *)
     | (_, _, Il.Imm (i, _)) when is_rm32 dst || is_r8 dst ->
-        let t = if signed then TY_u32 else TY_i32 in
+        let t = if signed then TY_i32 else TY_u32 in
           insn_rm_r_imm 0xc7 dst slash0 t i
 
     | _ -> raise Unrecognized
diff --git a/src/boot/me/trans.ml b/src/boot/me/trans.ml
index cb0b7c83..67a96030 100644
--- a/src/boot/me/trans.ml
+++ b/src/boot/me/trans.ml
@@ -316,6 +316,10 @@ let trans_visitor
     Il.Mem (mem, Il.ScalarTy (Il.ValTy word_bits))
   in
 
+  let imov (dst:Il.cell) (src:Il.operand) : unit =
+    emit (Il.imov dst src)
+  in
+
   let mov (dst:Il.cell) (src:Il.operand) : unit =
     emit (Il.umov dst src)
   in
@@ -398,8 +402,10 @@ let trans_visitor
     (in_quad_category "crate_rel -> ptr"
        (fun _ ->
           let cell = next_vreg_cell (Il.AddrTy rty) in
+          let diff = next_vreg_cell (Il.AddrTy rty) in
             mov cell (Il.Cell (curr_crate_ptr()));
-            add_to cell rel;
+            imov diff rel;
+            add_to cell (Il.Cell diff);
             cell))
 
   (* 
@@ -1566,7 +1572,7 @@ let trans_visitor
       Abi.load_fixup_addr (emitter())
         crate_ptr_reg cx.ctxt_crate_fixup Il.OpaqueTy;
       mov (word_at (fp_imm frame_crate_ptr)) (Il.Cell (crate_ptr_cell));
-      mov (word_at (fp_imm frame_fns_disp)) frame_fns
+      imov (word_at (fp_imm frame_fns_disp)) frame_fns
 
   and check_interrupt_flag _ =
     if cx.ctxt_sess.Session.sess_minimal
@@ -2307,7 +2313,7 @@ let trans_visitor
                 else Il.JL
               in
                 (* Start with assumption lhs < rhs *)
-                mov result neg_one;
+                imov result neg_one;
                 let lhs_lt_rhs_jmps =
                   trans_compare ~ty_params ~cjmp ~ty lhs rhs
                 in
-- 
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