Fix PR#6878: AArch64 conditional branches out of range. (Introduces n…

…ew, generic branch relaxation module.)

git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@16168 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

.depend

@@ -597,6 +597,8 @@ asmcomp/asmgen.cmi : bytecomp/lambda.cmi asmcomp/cmm.cmi
 asmcomp/asmlibrarian.cmi :
 asmcomp/asmlink.cmi : asmcomp/cmx_format.cmi
 asmcomp/asmpackager.cmi : typing/env.cmi
+asmcomp/branch_relaxation.cmi : asmcomp/linearize.cmi \
+    asmcomp/branch_relaxation_intf.cmo
 asmcomp/clambda.cmi : bytecomp/lambda.cmi typing/ident.cmi \
     asmcomp/debuginfo.cmi parsing/asttypes.cmi
 asmcomp/closure.cmi : bytecomp/lambda.cmi asmcomp/clambda.cmi
@@ -686,6 +688,14 @@ asmcomp/asmpackager.cmx : typing/typemod.cmx bytecomp/translmod.cmx \
     utils/config.cmx asmcomp/compilenv.cmx asmcomp/cmx_format.cmi \
     utils/clflags.cmx utils/ccomp.cmx asmcomp/asmlink.cmx asmcomp/asmgen.cmx \
     asmcomp/asmpackager.cmi
+asmcomp/branch_relaxation_intf.cmo : asmcomp/linearize.cmi asmcomp/arch.cmo
+asmcomp/branch_relaxation_intf.cmx : asmcomp/linearize.cmx asmcomp/arch.cmx
+asmcomp/branch_relaxation.cmo : utils/misc.cmi asmcomp/mach.cmi \
+    asmcomp/linearize.cmi asmcomp/cmm.cmi asmcomp/branch_relaxation_intf.cmo \
+    asmcomp/branch_relaxation.cmi
+asmcomp/branch_relaxation.cmx : utils/misc.cmx asmcomp/mach.cmx \
+    asmcomp/linearize.cmx asmcomp/cmm.cmx asmcomp/branch_relaxation_intf.cmx \
+    asmcomp/branch_relaxation.cmi
 asmcomp/clambda.cmo : bytecomp/lambda.cmi typing/ident.cmi \
     asmcomp/debuginfo.cmi parsing/asttypes.cmi asmcomp/clambda.cmi
 asmcomp/clambda.cmx : bytecomp/lambda.cmx typing/ident.cmx \
@@ -759,13 +769,13 @@ asmcomp/emitaux.cmx : asmcomp/linearize.cmx asmcomp/debuginfo.cmx \
 asmcomp/emit.cmo : asmcomp/reg.cmi asmcomp/proc.cmi utils/misc.cmi \
     asmcomp/mach.cmi asmcomp/linearize.cmi bytecomp/lambda.cmi \
     asmcomp/emitaux.cmi asmcomp/debuginfo.cmi utils/config.cmi \
-    asmcomp/compilenv.cmi asmcomp/cmm.cmi utils/clflags.cmi asmcomp/arch.cmo \
-    asmcomp/emit.cmi
+    asmcomp/compilenv.cmi asmcomp/cmm.cmi utils/clflags.cmi \
+    asmcomp/branch_relaxation.cmi asmcomp/arch.cmo asmcomp/emit.cmi
 asmcomp/emit.cmx : asmcomp/reg.cmx asmcomp/proc.cmx utils/misc.cmx \
     asmcomp/mach.cmx asmcomp/linearize.cmx bytecomp/lambda.cmx \
     asmcomp/emitaux.cmx asmcomp/debuginfo.cmx utils/config.cmx \
-    asmcomp/compilenv.cmx asmcomp/cmm.cmx utils/clflags.cmx asmcomp/arch.cmx \
-    asmcomp/emit.cmi
+    asmcomp/compilenv.cmx asmcomp/cmm.cmx utils/clflags.cmx \
+    asmcomp/branch_relaxation.cmx asmcomp/arch.cmx asmcomp/emit.cmi
 asmcomp/interf.cmo : asmcomp/reg.cmi asmcomp/proc.cmi asmcomp/mach.cmi \
     asmcomp/interf.cmi
 asmcomp/interf.cmx : asmcomp/reg.cmx asmcomp/proc.cmx asmcomp/mach.cmx \

Changes

@@ -200,6 +200,9 @@ Bug fixes:
 - PR#6872: Type-directed propagation fails to disambiguate variants
   that are also exception constructors
   (Jacques Garrigue, report by Romain Beauxis)
+- PR#6878: AArch64 backend generates invalid asm: conditional branch
+  out of range (Mark Shinwell, report by Richard Jones, testing by Richard
+  Jones and Xavier Leroy, code review by Xavier Leroy and Thomas Refis)
 - PR#6879: Wrong optimization of 1 mod n
   (Mark Shinwell, report by Jean-Christophe Filliâtre)
 - PR#6884: The __CYGWIN32__ #define should be replaced with __CYGWIN__

Makefile

@@ -94,6 +94,8 @@ ASMCOMP=asmcomp/arch.cmo asmcomp/debuginfo.cmo \
   asmcomp/deadcode.cmo \
   asmcomp/printlinear.cmo asmcomp/linearize.cmo \
   asmcomp/schedgen.cmo asmcomp/scheduling.cmo \
+  asmcomp/branch_relaxation_intf.cmo \
+  asmcomp/branch_relaxation.cmo \
   asmcomp/emitaux.cmo asmcomp/emit.cmo asmcomp/asmgen.cmo \
   asmcomp/asmlink.cmo asmcomp/asmlibrarian.cmo asmcomp/asmpackager.cmo \
   driver/opterrors.cmo driver/optcompile.cmo

asmcomp/amd64/emit.mlp

@@ -20,6 +20,12 @@ open Mach
 open Linearize
 open Emitaux
 
+(* [Branch_relaxation] is not used in this file, but is required by
+   emit.mlp files for certain other targets; the reference here ensures
+   that when releases are being prepared the .depend files are correct
+   for all targets. *)
+open! Branch_relaxation
+
 let macosx = (Config.system = "macosx")
 let mingw64 = (Config.system = "mingw64")
 let cygwin = (Config.system = "cygwin")

asmcomp/arm64/arch.ml

@@ -34,8 +34,12 @@ type addressing_mode =
 (* Specific operations *)
 
 type specific_operation =
+  | Ifar_alloc of int
+  | Ifar_intop_checkbound
+  | Ifar_intop_imm_checkbound of int
   | Ishiftarith of arith_operation * int
   | Ishiftcheckbound of int
+  | Ifar_shiftcheckbound of int
   | Imuladd       (* multiply and add *)
   | Imulsub       (* multiply and subtract *)
   | Inegmulf      (* floating-point negate and multiply *)
@@ -91,6 +95,12 @@ let print_addressing printreg addr ppf arg =
 
 let print_specific_operation printreg op ppf arg =
   match op with
+  | Ifar_alloc n ->
+    fprintf ppf "(far) alloc %i" n
+  | Ifar_intop_checkbound ->
+    fprintf ppf "%a (far) check > %a" printreg arg.(0) printreg arg.(1)
+  | Ifar_intop_imm_checkbound n ->
+    fprintf ppf "%a (far) check > %i" printreg arg.(0) n
   | Ishiftarith(op, shift) ->
       let op_name = function
       | Ishiftadd -> "+"
@@ -103,6 +113,9 @@ let print_specific_operation printreg op ppf arg =
        printreg arg.(0) (op_name op) printreg arg.(1) shift_mark
   | Ishiftcheckbound n ->
       fprintf ppf "check %a >> %i > %a" printreg arg.(0) n printreg arg.(1)
+  | Ifar_shiftcheckbound n ->
+      fprintf ppf
+        "(far) check %a >> %i > %a" printreg arg.(0) n printreg arg.(1)
   | Imuladd ->
       fprintf ppf "(%a * %a) + %a"
         printreg arg.(0)