Add ocaml-common-4_14-a09-debuggasx86 patch

Fixes #8

Author: jonahbeckford

src/p/ocaml-common-4_14-a09-debuggasx86.md

@@ -0,0 +1,40 @@
+# GNU as x86/x86_64 debugging
+
+The `asmcomp/x86_gas.ml` module (used by both IA-64 and IA-32) places `.file ""` at the top
+of each GNU `as` assembly source file.
+That is done to create reproducible builds: <https://github.com/ocaml/ocaml/issues/7037>.
+
+However, we get:
+
+```text
+./BOOT_OCAMLC -stdlib.s: Assembler messages:
+stdlib.s:1009: Error: file number 1 already allocated
+File "/work/build/DkSDKFiles/cfg-Debug/o/src/ocaml/stdlib/stdlib.ml", line 1:
+Error: Assembler error, input left in file /work/build/DkSDKFiles/cfg-Debug/o/src/ocaml/stdlib/stdlib.s
+make[2]: *** [stdlib.cmx] Error 2
+make[1]: *** [libraryopt] Error 2
+make: *** [opt-core] Error 2
+FATAL: make opt-core -j6 -l6 failed
+```
+
+That is because the `.file ""` seems to be treated as an implicit file number 1,
+which is re-used in:
+
+```asm
+; ...
+ .globl camlStdlib__failwith_7
+camlStdlib__failwith_7:
+ .file 1 "stdlib.ml"
+ .loc 1 29 13
+; ...
+.L352:
+ movl %eax, %edx
+ movl %edx, (%esp)
+ .file 2 "camlinternalAtomic.ml"
+ .loc 2 27 13
+```
+
+The patch does the following:
+
+1. Starts the file numbering from 2, not 1.
+2. Changes `.file ""` to `.file 1 ""` to avoid `Error: unassigned file number 1`.

src/p/ocaml-common-4_14-a09-debuggasx86.patch

@@ -0,0 +1,66 @@
+diff --git a/asmcomp/amd64/emit.mlp b/asmcomp/amd64/emit.mlp
+index 3c58633..f69d42e 100644
+--- a/asmcomp/amd64/emit.mlp
++++ b/asmcomp/amd64/emit.mlp
+@@ -922,7 +922,7 @@ let data l =
+ 
+ let begin_assembly() =
+   X86_proc.reset_asm_code ();
+-  reset_debug_info();                   (* PR#5603 *)
++  reset_debug_info_at_file_num 2;       (* A09. PR#5603 *)
+   reset_imp_table();
+   float_constants := [];
+   all_functions := [];
+diff --git a/asmcomp/emitaux.ml b/asmcomp/emitaux.ml
+index d3587c1..0dca6a9 100644
+--- a/asmcomp/emitaux.ml
++++ b/asmcomp/emitaux.ml
+@@ -341,6 +341,10 @@ let reset_debug_info () =
+   file_pos_nums := [];
+   file_pos_num_cnt := 1
+ 
++let reset_debug_info_at_file_num file_num =
++  file_pos_nums := [];
++  file_pos_num_cnt := file_num
++
+ (* We only display .file if the file has not been seen before. We
+    display .loc for every instruction. *)
+ let emit_debug_info_gen dbg file_emitter loc_emitter =
+diff --git a/asmcomp/emitaux.mli b/asmcomp/emitaux.mli
+index df0b019..34d1ac1 100644
+--- a/asmcomp/emitaux.mli
++++ b/asmcomp/emitaux.mli
+@@ -32,6 +32,7 @@ val emit_float32_directive: string -> int32 -> unit
+ 
+ val reset : unit -> unit
+ val reset_debug_info: unit -> unit
++val reset_debug_info_at_file_num: int -> unit
+ val emit_debug_info: Debuginfo.t -> unit
+ val emit_debug_info_gen :
+   Debuginfo.t ->
+diff --git a/asmcomp/i386/emit.mlp b/asmcomp/i386/emit.mlp
+index b76af36..69489a2 100644
+--- a/asmcomp/i386/emit.mlp
++++ b/asmcomp/i386/emit.mlp
+@@ -948,7 +948,7 @@ let data l =
+ 
+ let begin_assembly() =
+   X86_proc.reset_asm_code ();
+-  reset_debug_info();                   (* PR#5603 *)
++  reset_debug_info_at_file_num 2;       (* A09. PR#5603 *)
+   float_constants := [];
+   if system = S_win32 then begin
+     D.mode386 ();
+diff --git a/asmcomp/x86_gas.ml b/asmcomp/x86_gas.ml
+index 6d2363a..9548e91 100644
+--- a/asmcomp/x86_gas.ml
++++ b/asmcomp/x86_gas.ml
+@@ -300,7 +300,7 @@ let print_line b = function
+ 
+ let generate_asm oc lines =
+   let b = Buffer.create 10000 in
+-  output_string oc "\t.file \"\"\n"; (* PR#7037 *)
++  output_string oc "\t.file 1 \"\"\n"; (* A09. PR#7037 *)
+   List.iter
+     (fun i ->
+        Buffer.clear b;