Hello,This patch proposes a solution to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53929, and is required by https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80881.
I have so far bootstrapped master on i686-w64-mingw32 with DWARF2 exception model, and on x86_64-w64-mingw32 with SEH exception model, both patched to use Intel syntax by default. I have also bootstrapped on x86_64-linux-gnu with default AT&T syntax, and verified that it produces expected assembly with `-masm=intel`.
-- Best regards, LIU Hao
From 07baacbc7de1f5dc5db9e834b030c1b642774a37 Mon Sep 17 00:00:00 2001 From: LIU Hao <lh_mo...@126.com> Date: Thu, 20 Feb 2025 18:12:14 +0800 Subject: [PATCH] i386: Quote user-defined symbols in assembly in Intel syntax With `-masm=intel`, GCC generates registers without % prefixes. If a user-declared symbol happens to match a register, it will confuse the assembler. User-defined symbols should be quoted, so they are not to be mistaken for registers or operators. Support for quoted symbols were added in Binutils 2.26, originally for ARM assembly, where registers are also unprefixed: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d02603dc201f80cd9d2a1f4b1a16110b1e04222b This change is required for `@SECREL32` to work in Intel syntax when targeting Windows, where `@` is allowed as part of a symbol. GNU AS fails to parse a plain symbol with that suffix: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80881#c79 gcc/config/: PR target/53929 PR target/80881 * gcc/config/i386/i386-protos.h (ix86_asm_output_labelref): Declare new function for quoting user-defined symbols in Intel syntax. * gcc/config/i386/i386.cc (ix86_asm_output_labelref): Implement it. * gcc/config/i386/i386.h (ASM_OUTPUT_LABELREF): Use it. * gcc/config/i386/cygming.h (ASM_OUTPUT_LABELREF): Use it. --- gcc/config/i386/cygming.h | 5 +++-- gcc/config/i386/i386-protos.h | 1 + gcc/config/i386/i386.cc | 22 ++++++++++++++++++++++ gcc/config/i386/i386.h | 7 +++++++ 4 files changed, 33 insertions(+), 2 deletions(-) diff --git a/gcc/config/i386/cygming.h b/gcc/config/i386/cygming.h index 3ddcbecb22fd..4a192900045a 100644 --- a/gcc/config/i386/cygming.h +++ b/gcc/config/i386/cygming.h @@ -247,9 +247,10 @@ do { \ #undef ASM_OUTPUT_LABELREF #define ASM_OUTPUT_LABELREF(STREAM, NAME) \ do { \ + const char* prefix = ""; \ if ((NAME)[0] != FASTCALL_PREFIX) \ - fputs (user_label_prefix, (STREAM)); \ - fputs ((NAME), (STREAM)); \ + prefix = user_label_prefix; \ + ix86_asm_output_labelref ((STREAM), prefix, (NAME)); \ } while (0) /* This does much the same in memory rather than to a stream. */ diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h index bea3fd4b2e2a..3b9e28ced91c 100644 --- a/gcc/config/i386/i386-protos.h +++ b/gcc/config/i386/i386-protos.h @@ -198,6 +198,7 @@ extern int ix86_attr_length_vex_default (rtx_insn *, bool, bool); extern rtx ix86_libcall_value (machine_mode); extern bool ix86_function_arg_regno_p (int); extern void ix86_asm_output_function_label (FILE *, const char *, tree); +extern void ix86_asm_output_labelref (FILE *, const char *, const char *); extern void ix86_call_abi_override (const_tree); extern int ix86_reg_parm_stack_space (const_tree); diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index 3128973ba79c..6cbed7e4906e 100644 --- a/gcc/config/i386/i386.cc +++ b/gcc/config/i386/i386.cc @@ -1709,6 +1709,28 @@ ix86_asm_output_function_label (FILE *out_file, const char *fname, } } +/* Output a user-defined label. In AT&T syntax, registers are prefixed + with %, so labels require no punctuation. In Intel syntax, registers + are unprefixed, so labels may clash with registers or other operators, + and require quoting. */ +void +ix86_asm_output_labelref (FILE *file, const char *prefix, const char *label) +{ + if (ASSEMBLER_DIALECT != ASM_INTEL) + fprintf (file, "%s%s", prefix, label); + else + { + /* When generating DWARF2 debug info, GCC may emit an expression + like `label+42`, where only `label` shall be quoted. */ + const char* op = strpbrk (label, "+-"); + if (op == NULL) + fprintf (file, "\"%s%s\"", prefix, label); + else + fprintf (file, "\"%s%.*s\"%s", + prefix, static_cast<int> (op - label), label, op); + } +} + /* Implementation of call abi switching target hook. Specific to FNDECL the specific call register sets are set. See also ix86_conditional_register_usage for more details. */ diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h index 40b1aa4e6dfe..79a1afdde02c 100644 --- a/gcc/config/i386/i386.h +++ b/gcc/config/i386/i386.h @@ -2251,6 +2251,13 @@ extern unsigned int const svr4_debugger_register_map[FIRST_PSEUDO_REGISTER]; } while (0) #endif +/* In Intel syntax, we have to quote user-defined labels that would + match (unprefixed) registers or operators. */ + +#undef ASM_OUTPUT_LABELREF +#define ASM_OUTPUT_LABELREF(STREAM, NAME) \ + ix86_asm_output_labelref ((STREAM), user_label_prefix, (NAME)) + /* Under some conditions we need jump tables in the text section, because the assembler cannot handle label differences between sections. */ -- 2.48.1
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