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String literals in asm files: use asm quoting conventions, not OCaml's #588

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Merged
xavierleroy merged 2 commits into from
Jul 14, 2026
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String literals in asm files: use asm quoting conventions, not OCaml's #588

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7ba07bc
String literals in asm files: use asm quoting conventions, not OCaml's
xavierleroy Jul 11, 2026
fcda834
PrintAsmaux.quote_string: use `\n` and `\t` escapes
xavierleroy Jul 14, 2026
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2 changes: 1 addition & 1 deletion aarch64/TargetPrinter.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -612,7 +612,7 @@ module Target(System: SYSTEM): TARGET =
| EF_annot(kind,txt, targs) ->
begin match (P.to_int kind) with
| 1 -> let annot = annot_text preg_annot "sp" txt args in
fprintf oc "%s annotation: %S\n" comment annot
fprintf oc "%s annotation: %s\n" comment (quote_string annot)
| 2 -> let lbl = new_label () in
fprintf oc "%a:\n" label lbl;
add_ais_annot lbl preg_annot "sp" txt args
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2 changes: 1 addition & 1 deletion arm/TargetPrinter.ml
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Expand Up @@ -477,7 +477,7 @@ struct
| EF_annot(kind,txt, targs) ->
begin match (P.to_int kind) with
| 1 -> let annot = annot_text preg_annot "sp" txt args in
fprintf oc "%s annotation: %S\n" comment annot
fprintf oc "%s annotation: %s\n" comment (quote_string annot)
| 2 -> let lbl = new_label () in
fprintf oc "%a:\n" label lbl;
AisAnnot.add_ais_annot lbl preg_annot "r13" txt args
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5 changes: 3 additions & 2 deletions backend/Fileinfo.ml
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Expand Up @@ -12,6 +12,7 @@
(* *********************************************************************)

open Printf
open PrintAsmaux

(* Printing annotations in asm syntax *)

Expand Down Expand Up @@ -47,7 +48,7 @@ let print_file oc file =
Hashtbl.find filename_info file
with Not_found ->
let (filenum, filebuf as res) = enter_filename file in
fprintf oc " .file %d %S\n" filenum file;
fprintf oc " .file %d %s\n" filenum (quote_string file);
res

let print_file_line oc pref file line =
Expand All @@ -70,7 +71,7 @@ let print_file_line_d2 oc pref file line =
with Not_found ->
enter_filename file in
if file <> !last_file then begin
fprintf oc " .d2file %S\n" file;
fprintf oc " .d2file %s\n" (quote_string file);
last_file := file
end;
fprintf oc " .d2line %d\n" line;
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2 changes: 1 addition & 1 deletion backend/PrintAsm.ml
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Expand Up @@ -180,7 +180,7 @@ module Printer(Target:TARGET) =
print_addr oc Target.label lbl
| AisAnnot.Symbol symb ->
print_addr oc Target.symbol symb
| AisAnnot.String a -> fprintf oc " .ascii %S\n" a in
| AisAnnot.String a -> fprintf oc " .ascii %s\n" (quote_string a) in
let annot oc str =
List.iter (annot_part oc) str
in
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23 changes: 22 additions & 1 deletion backend/PrintAsmaux.ml
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Expand Up @@ -289,6 +289,27 @@ let print_inline_asm print_preg oc txt sg args res =
List.iter print_fragment (Str.full_split re_asm_param_1 txt);
fprintf oc "\n"

(** Quote the given string, using C string literal syntax.
The resulting string is enclosed in double quotes.
Double quotes and backslash are backslash-escaped.
Newline and tabs are written as [\n] and [\t].
Other control characters are octal-encoded. *)

let quote_string s =
let b = Buffer.create (String.length s + 10) in
Buffer.add_char b '"';
String.iter
(fun c ->
match c with
| '"' | '\\' -> Buffer.add_char b '\\'; Buffer.add_char b c
| '\n' -> Buffer.add_string b "\\n"
| '\t' -> Buffer.add_string b "\\t"
| '\x00' .. '\x1F' -> Printf.bprintf b "\\%03o" (Char.code c)

@m-schmidt m-schmidt Jul 13, 2026

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What about quoting at least newline and tab as "\n" and "\t" instead of octal for readability?

@xavierleroy xavierleroy Jul 14, 2026

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Yes, let's do that. Commit fcda834.

@m-schmidt m-schmidt Jul 14, 2026

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Looks good. Thanks!

| _ -> Buffer.add_char b c)
s;
Buffer.add_char b '"';
Buffer.contents b

(** This is [String.exists] in OCaml 4.13 and up. Temporarily included here
to support older OCaml versions. *)

Expand All @@ -308,7 +329,7 @@ let quote_argument s =
if string_exists
(function '\x00'..'\x1F' | ' ' | '"' -> true | _ -> false)
s
then "\"" ^ String.escaped s ^ "\""
then quote_string s
else s

(** Print CompCert version and command-line as asm comment *)
Expand Down
8 changes: 4 additions & 4 deletions debug/DwarfPrinter.ml
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Expand Up @@ -322,10 +322,10 @@ module DwarfPrinter(Target: DWARF_TARGET):

let print_string oc c = function
| Simple_string s ->
fprintf oc " .asciz %S%a\n" s print_comment c
fprintf oc " .asciz %s%a\n" (quote_string s) print_comment c
| Offset_string (o,s) ->
let c = sprintf "%s %s" c s in
print_loc_ref oc c o
let c = sprintf "%s %s" c (quote_string s) in
print_loc_ref oc c o

let print_uleb128 oc c d =
fprintf oc " .uleb128 %d%a\n" d print_comment c
Expand Down Expand Up @@ -693,7 +693,7 @@ module DwarfPrinter(Target: DWARF_TARGET):
let s = List.sort (fun (a,_) (b,_) -> compare a b) entries.string_table in
List.iter (fun (id,s) ->
print_label oc (loc_to_label id);
fprintf oc " .asciz %S\n" s) s)
fprintf oc " .asciz %s\n" (quote_string s)) s)


(* Print the debug info and abbrev section *)
Expand Down
2 changes: 1 addition & 1 deletion powerpc/TargetPrinter.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -812,7 +812,7 @@ module Target (System : SYSTEM):TARGET =
| EF_annot(kind,txt, targs) ->
begin match (P.to_int kind) with
| 1 -> let annot = annot_text preg_annot "sp" txt args in
fprintf oc "%s annotation: %S\n" comment annot
fprintf oc "%s annotation: %s\n" comment (quote_string annot)

| 2 -> let lbl = new_label () in
fprintf oc "%a:\n" label lbl;
Expand Down
2 changes: 1 addition & 1 deletion riscV/TargetPrinter.ml
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Expand Up @@ -543,7 +543,7 @@ module Target : TARGET =
| EF_annot(kind,txt, targs) ->
begin match (P.to_int kind) with
| 1 -> let annot = annot_text preg_annot "x2" txt args in
fprintf oc "%s annotation: %S\n" comment annot
fprintf oc "%s annotation: %s\n" comment (quote_string annot)
| 2 -> let lbl = new_label () in
fprintf oc "%a:\n" label lbl;
add_ais_annot lbl preg_annot "x2" txt args
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2 changes: 1 addition & 1 deletion x86/TargetPrinter.ml
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Expand Up @@ -864,7 +864,7 @@ module Target(System: SYSTEM):TARGET =
| EF_annot(kind,txt, targs) ->
begin match (P.to_int kind) with
| 1 -> let annot = annot_text preg_annot "esp" txt args in
fprintf oc "%s annotation: %S\n" comment annot
fprintf oc "%s annotation: %s\n" comment (quote_string annot)
| 2 -> let lbl = new_label () in
fprintf oc "%a:\n" label lbl;
let sp = if Archi.ptr64 then "rsp" else "esp" in
Expand Down
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