Hi!
In AT&T syntax leading $ is special, so if we have identifiers that start
with dollar, we usually fail to assemble it (or assemble incorrectly).
As mentioned in the PR, what works is wrapping the identifiers inside of
parens, like:
movl $($a), %eax
leaq ($a)(,%rdi,4), %rax
movl ($a)(%rip), %eax
movl ($a)+16(%rip), %eax
.globl $a
.type $a, @object
.size $a, 72
$a:
.string "$a"
.quad ($a)
(this is x86_64 -fno-pic -O2). In some places ($a) is not accepted,
like as .globl operand, in .type, .size, so the patch overrides
ASM_OUTPUT_SYMBOL_REF rather than e.g. ASM_OUTPUT_LABELREF.
I didn't want to duplicate what assemble_name is doing (following
transparent aliases), so split assemble_name into two parts; just
mere looking at the first character of a name before calling assemble_name
wouldn't be good enough, a transparent alias could lead from a name
not starting with $ to one starting with it and vice versa.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2020-01-18 Jakub Jelinek <ja...@redhat.com>
PR target/91298
* output.h (assemble_name_resolve): Declare.
* varasm.c (assemble_name_resolve): New function.
(assemble_name): Use it.
* config/i386/i386.h (ASM_OUTPUT_SYMBOL_REF): Define.
* gcc.target/i386/pr91298-1.c: New test.
* gcc.target/i386/pr91298-2.c: New test.
--- gcc/output.h.jj 2020-01-12 11:54:36.692409199 +0100
+++ gcc/output.h 2020-01-17 09:51:27.606873017 +0100
@@ -237,6 +237,12 @@ extern void assemble_label (FILE *, cons
addition of an underscore). */
extern void assemble_name_raw (FILE *, const char *);
+/* Return NAME that should actually be emitted, looking through
+ transparent aliases. If NAME refers to an entity that is also
+ represented as a tree (like a function or variable), mark the entity
+ as referenced. */
+extern const char *assemble_name_resolve (const char *);
+
/* Like assemble_name_raw, but should be used when NAME might refer to
an entity that is also represented as a tree (like a function or
variable). If NAME does refer to such an entity, that entity will
--- gcc/varasm.c.jj 2020-01-12 11:54:38.533381424 +0100
+++ gcc/varasm.c 2020-01-17 09:53:14.430239885 +0100
@@ -2589,20 +2589,16 @@ assemble_name_raw (FILE *file, const cha
ASM_OUTPUT_LABELREF (file, name);
}
-/* Like assemble_name_raw, but should be used when NAME might refer to
- an entity that is also represented as a tree (like a function or
- variable). If NAME does refer to such an entity, that entity will
- be marked as referenced. */
-
-void
-assemble_name (FILE *file, const char *name)
+/* Return NAME that should actually be emitted, looking through
+ transparent aliases. If NAME refers to an entity that is also
+ represented as a tree (like a function or variable), mark the entity
+ as referenced. */
+const char *
+assemble_name_resolve (const char *name)
{
- const char *real_name;
- tree id;
+ const char *real_name = targetm.strip_name_encoding (name);
+ tree id = maybe_get_identifier (real_name);
- real_name = targetm.strip_name_encoding (name);
-
- id = maybe_get_identifier (real_name);
if (id)
{
tree id_orig = id;
@@ -2614,7 +2610,18 @@ assemble_name (FILE *file, const char *n
gcc_assert (! TREE_CHAIN (id));
}
- assemble_name_raw (file, name);
+ return name;
+}
+
+/* Like assemble_name_raw, but should be used when NAME might refer to
+ an entity that is also represented as a tree (like a function or
+ variable). If NAME does refer to such an entity, that entity will
+ be marked as referenced. */
+
+void
+assemble_name (FILE *file, const char *name)
+{
+ assemble_name_raw (file, assemble_name_resolve (name));
}
/* Allocate SIZE bytes writable static space with a gensym name
--- gcc/config/i386/i386.h.jj 2020-01-17 09:22:47.524148012 +0100
+++ gcc/config/i386/i386.h 2020-01-17 10:21:10.822480641 +0100
@@ -2258,6 +2258,31 @@ extern int const svr4_dbx_register_map[F
#define ASM_OUTPUT_FUNCTION_LABEL(FILE, NAME, DECL) \
ix86_asm_output_function_label ((FILE), (NAME), (DECL))
+/* A C statement (sans semicolon) to output a reference to SYMBOL_REF SYM.
+ If not defined, assemble_name will be used to output the name of the
+ symbol. This macro may be used to modify the way a symbol is referenced
+ depending on information encoded by TARGET_ENCODE_SECTION_INFO. */
+
+#ifndef ASM_OUTPUT_SYMBOL_REF
+#define ASM_OUTPUT_SYMBOL_REF(FILE, SYM) \
+ do { \
+ const char *name \
+ = assemble_name_resolve (XSTR (x, 0)); \
+ /* In -masm=att wrap identifiers that start with $ \
+ into parens. */ \
+ if (name[0] == '$' \
+ && user_label_prefix[0] == '\0' \
+ && ASSEMBLER_DIALECT == ASM_ATT) \
+ { \
+ fputc ('(', (FILE)); \
+ assemble_name_raw ((FILE), name); \
+ fputc (')', (FILE)); \
+ } \
+ else \
+ assemble_name_raw ((FILE), name); \
+ } while (0)
+#endif
+
/* Under some conditions we need jump tables in the text section,
because the assembler cannot handle label differences between
sections. This is the case for x86_64 on Mach-O for example. */
--- gcc/testsuite/gcc.target/i386/pr91298-1.c.jj 2020-01-17
10:45:24.172222204 +0100
+++ gcc/testsuite/gcc.target/i386/pr91298-1.c 2020-01-17 10:44:46.388800409
+0100
@@ -0,0 +1,14 @@
+/* PR target/91298 */
+/* { dg-do assemble } */
+/* { dg-options "-O2 -g -fdollars-in-identifiers" } */
+
+int $a[18];
+int *foo (void) { return &$a[0]; }
+int *bar (int x) { return &$a[x]; }
+int baz (void) { return $a[0]; }
+int qux (void) { return $a[4]; }
+int $quux (void) { return 1; }
+int corge (void) { return $quux (); }
+int grault (void) { return $quux () + 1; }
+typedef int (*fn) (void);
+fn foobar (void) { return $quux; }
--- gcc/testsuite/gcc.target/i386/pr91298-2.c.jj 2020-01-17
10:45:30.834120262 +0100
+++ gcc/testsuite/gcc.target/i386/pr91298-2.c 2020-01-17 10:45:57.460712790
+0100
@@ -0,0 +1,5 @@
+/* PR target/91298 */
+/* { dg-do assemble { target fpic } } */
+/* { dg-options "-O2 -g -fdollars-in-identifiers -fpic" } */
+
+#include "pr91298-1.c"
Jakub
