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* [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry
@ 2021-02-23 11:37 huangpei at loongson dot cn
2021-02-23 19:44 ` [Bug target/99217] " pinskia at gcc dot gnu.org
` (6 more replies)
0 siblings, 7 replies; 8+ messages in thread
From: huangpei at loongson dot cn @ 2021-02-23 11:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
Bug ID: 99217
Summary: [MIPS] wrong function entry with
-fpatchable-function-entry
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: huangpei at loongson dot cn
Target Milestone: ---
On Debian AMD64 unstable,
-----------------
depaulose@localhost:~$ cat a.c
void f() {}
depaulose@localhost:~$ gcc -fpatchable-function-entry=3 -c a.c
depaulose@localhost:~$ objdump -d a.o
a.o: file format elf64-tradlittlemips
Disassembly of section .text:
0000000000000000 <f-0xc>:
...
000000000000000c <f>:
c: 67bdfff0 daddiu sp,sp,-16
10: ffbe0008 sd s8,8(sp)
14: 03a0f025 move s8,sp
18: 00000000 nop
1c: 03c0e825 move sp,s8
20: dfbe0008 ld s8,8(sp)
24: 67bd0010 daddiu sp,sp,16
28: 03e00008 jr ra
2c: 00000000 nop
depaulose@localhost:~$ readelf -s a.o
Symbol table '.symtab' contains 14 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS a.c
2: 0000000000000000 0 SECTION LOCAL DEFAULT 1
3: 0000000000000000 0 SECTION LOCAL DEFAULT 2
4: 0000000000000000 0 SECTION LOCAL DEFAULT 3
5: 0000000000000000 0 SECTION LOCAL DEFAULT 8
6: 0000000000000000 0 SECTION LOCAL DEFAULT 9
7: 0000000000000000 0 SECTION LOCAL DEFAULT 12
8: 0000000000000000 0 SECTION LOCAL DEFAULT 4
9: 0000000000000000 0 SECTION LOCAL DEFAULT 5
10: 0000000000000000 0 SECTION LOCAL DEFAULT 6
11: 0000000000000000 0 SECTION LOCAL DEFAULT 11
12: 0000000000000000 0 SECTION LOCAL DEFAULT 13
13: 000000000000000c 36 FUNC GLOBAL DEFAULT 1 f
depaulose@localhost:~$ gcc --version
gcc (Debian 10.2.1-6) 10.2.1 20210110
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
depaulose@localhost:~$ as --version
GNU assembler (GNU Binutils for Debian) 2.35.2
Copyright (C) 2020 Free Software Foundation, Inc.
This assembler was configured for a target of `mips64el-linux-gnuabi64'.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or later.
This program has absolutely no warranty.
This assembler was configured for a target of `mips64el-linux-gnuabi64'.
------------------
It turned out that function address is wrong. It is expected that the function
entry is 0 not 0xc
On Debian 10 , for arm64, same file
--------------------------
ambrosehua@ambrosehua-HP-xw6600-Workstation:Downloads$ aarch64-linux-gnu-gcc-8
-fpatchable-function-entry=3 -c a.c
ambrosehua@ambrosehua-HP-xw6600-Workstation:Downloads$
aarch64-linux-gnu-objdump -d a.o
a.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <f>:
0: d503201f nop
4: d503201f nop
8: d503201f nop
c: d503201f nop
10: d65f03c0 ret
ambrosehua@ambrosehua-HP-xw6600-Workstation:Downloads$ readelf -s a.o
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS a.c
2: 0000000000000000 0 SECTION LOCAL DEFAULT 1
3: 0000000000000000 0 SECTION LOCAL DEFAULT 2
4: 0000000000000000 0 SECTION LOCAL DEFAULT 3
5: 0000000000000000 0 NOTYPE LOCAL DEFAULT 1 $x
6: 0000000000000000 0 SECTION LOCAL DEFAULT 4
7: 0000000000000000 0 SECTION LOCAL DEFAULT 7
8: 0000000000000014 0 NOTYPE LOCAL DEFAULT 8 $d
9: 0000000000000000 0 SECTION LOCAL DEFAULT 8
10: 0000000000000000 0 SECTION LOCAL DEFAULT 6
11: 0000000000000000 20 FUNC GLOBAL DEFAULT 1 f
----------------------
here function address of f is right
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
@ 2021-02-23 19:44 ` pinskia at gcc dot gnu.org
2021-03-04 2:07 ` huangpei at loongson dot cn
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-02-23 19:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Component|c |target
Keywords| |wrong-code
Last reconfirmed| |2021-02-23
Target| |mips*-linux-gnu
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
.globl f
.section __patchable_function_entries,"aw",@progbits
.align 3
.8byte .LPFE1
.text
.LPFE1:
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.LFB0 = .
.cfi_startproc
.set nomips16
.set nomicromips
.ent f
.type f, @function
f:
---- CUT ---
AARCH64 does:
f:
.section __patchable_function_entries,"aw",@progbits
.align 3
.8byte .LPFE1
.text
.LPFE1:
nop
nop
nop
.LFB0:
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
2021-02-23 19:44 ` [Bug target/99217] " pinskia at gcc dot gnu.org
@ 2021-03-04 2:07 ` huangpei at loongson dot cn
2021-03-04 3:20 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: huangpei at loongson dot cn @ 2021-03-04 2:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
--- Comment #2 from huangpei at loongson dot cn <huangpei at loongson dot cn> ---
my colleague Xu Chenghua (xuchenghua@loongson.cn) add a patch to address this
--------------------
diff --git a/src/gcc/config/mips/mips-protos.h
b/src/gcc/config/mips/mips-protos.h
index aba1f8222..253c5b6f5 100644
--- a/src/gcc/config/mips/mips-protos.h
+++ b/src/gcc/config/mips/mips-protos.h
@@ -394,4 +394,6 @@ extern void mips_expand_vec_cond_expr (machine_mode,
machine_mode, rtx *);
/* Routines implemented in mips-d.c */
extern void mips_d_target_versions (void);
+extern void mips_declare_function_name (FILE *, const char *, tree);
+
#endif /* ! GCC_MIPS_PROTOS_H */
diff --git a/src/gcc/config/mips/mips.c b/src/gcc/config/mips/mips.c
index de69400d1..f94028e55 100644
--- a/src/gcc/config/mips/mips.c
+++ b/src/gcc/config/mips/mips.c
@@ -12002,6 +12002,23 @@ mips_output_cplocal (void)
output_asm_insn (".cplocal %+", 0);
}
+/* Implement ASM_DECLARE_FUNCTION_NAME. */
+
+void mips_declare_function_name(FILE *stream ATTRIBUTE_UNUSED,
+ const char *name, tree fndecl ATTRIBUTE_UNUSED)
+{
+
+ /* Get the function name the same way that toplev.c does before calling
+ assemble_start_function. This is needed so that the name used here
+ exactly matches the name used in ASM_DECLARE_FUNCTION_NAME. */
+ //fnname = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
+ mips_start_function_definition (name, TARGET_MIPS16);
+
+ //ASM_OUTPUT_TYPE_DIRECTIVE (stream, name, "function");
+ //ASM_OUTPUT_LABEL (stream, name);
+}
+
+
/* Implement TARGET_OUTPUT_FUNCTION_PROLOGUE. */
static void
@@ -12016,12 +12033,6 @@ mips_output_function_prologue (FILE *file)
&& crtl->args.info.fp_code != 0)
mips16_build_function_stub ();
- /* Get the function name the same way that toplev.c does before calling
- assemble_start_function. This is needed so that the name used here
- exactly matches the name used in ASM_DECLARE_FUNCTION_NAME. */
- fnname = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
- mips_start_function_definition (fnname, TARGET_MIPS16);
-
/* Output MIPS-specific frame information. */
if (!flag_inhibit_size_directive)
{
diff --git a/src/gcc/config/mips/mips.h b/src/gcc/config/mips/mips.h
index dccfae52c..cb8ab602a 100644
--- a/src/gcc/config/mips/mips.h
+++ b/src/gcc/config/mips/mips.h
@@ -2955,7 +2955,8 @@ while (0)
is not declared before the .ent directive elsewhere. */
#undef ASM_DECLARE_FUNCTION_NAME
-#define ASM_DECLARE_FUNCTION_NAME(STREAM,NAME,DECL)
+#define ASM_DECLARE_FUNCTION_NAME(STREAM,NAME,DECL) \
+ mips_declare_function_name(STREAM,NAME,DECL)
/* This is how to store into the string LABEL
the symbol_ref name of an internal numbered label where
diff --git a/src/gcc/targhooks.c b/src/gcc/targhooks.c
index fafcc6c51..9a6baaf4b 100644
--- a/src/gcc/targhooks.c
+++ b/src/gcc/targhooks.c
@@ -1806,7 +1806,7 @@ default_print_patchable_function_entry (FILE *file,
unsigned i;
for (i = 0; i < patch_area_size; ++i)
- fprintf (file, "\t%s\n", nop_templ);
+ output_asm_insn (nop_templ, NULL);
}
bool
--------------------------
With this and fix for bug 93242, -fpatchable-function-entry works on linux
kernel 5.10
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
2021-02-23 19:44 ` [Bug target/99217] " pinskia at gcc dot gnu.org
2021-03-04 2:07 ` huangpei at loongson dot cn
@ 2021-03-04 3:20 ` pinskia at gcc dot gnu.org
2021-03-05 7:22 ` huangpei at loongson dot cn
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-03-04 3:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |pinskia at gcc dot gnu.org
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to huangpei@loongson.cn from comment #2)
> my colleague Xu Chenghua (xuchenghua@loongson.cn) add a patch to address this
This patch is close, though it needs to move the call to
mips16_build_function_stub also.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
` (2 preceding siblings ...)
2021-03-04 3:20 ` pinskia at gcc dot gnu.org
@ 2021-03-05 7:22 ` huangpei at loongson dot cn
2021-12-04 7:54 ` huangpei at loongson dot cn
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: huangpei at loongson dot cn @ 2021-03-05 7:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
--- Comment #4 from huangpei at loongson dot cn <huangpei at loongson dot cn> ---
what do you mean " move the call to mips16_build_function_stub" ?
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
` (3 preceding siblings ...)
2021-03-05 7:22 ` huangpei at loongson dot cn
@ 2021-12-04 7:54 ` huangpei at loongson dot cn
2021-12-15 10:00 ` huangpei at loongson dot cn
2021-12-15 10:01 ` huangpei at loongson dot cn
6 siblings, 0 replies; 8+ messages in thread
From: huangpei at loongson dot cn @ 2021-12-04 7:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
--- Comment #5 from huangpei at loongson dot cn <huangpei at loongson dot cn> ---
Hi, with this fix and bug 93242 fixed, a.c with mips16 is OK,
ambrosehua@3A1000-800M:~$ gcc -fpatchable-function-entry=3 -mips16 -mabi=32
-c a.c -S -o a.1.s
ambrosehua@3A1000-800M:~$ cat a.1.s
.file 1 "a.c"
.section .mdebug.abi32
.previous
.nan legacy
.module fp=xx
.module nooddspreg
.abicalls
.text
.align 2
.globl f
.set mips16
.set nomicromips
.ent f
.type f, @function
f:
.section __patchable_function_entries,"a",@progbits
.4byte $LPFE1
.text
$LPFE1:
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.frame $17,8,$31 # vars= 0, regs= 1/0, args= 0, gp= 0
.mask 0x00020000,-4
.fmask 0x00000000,0
save 8,$17
move $17,$sp
.set noreorder
nop
.set reorder
move $sp,$17
restore 8,$17
jr $31
.end f
.size f, .-f
.ident "GCC: (Debian 8.3.0-8.lnd.4) 8.3.0"
ambrosehua@3A1000-800M:~$ objdump -tdr a.1.o
a.1.o: file format elf32-tradlittlemips
SYMBOL TABLE:
00000000 l df *ABS* 00000000 a.c
00000000 l d .text 00000000 .text
00000000 l d .data 00000000 .data
00000000 l d .bss 00000000 .bss
00000000 l d .mdebug.abi32 00000000 .mdebug.abi32
00000000 l d __patchable_function_entries 00000000
__patchable_function_entries
00000000 l .text 00000000 0xf0 $LPFE1
00000000 l d .reginfo 00000000 .reginfo
00000000 l d .MIPS.abiflags 00000000 .MIPS.abiflags
00000000 l d .pdr 00000000 .pdr
00000000 l d .comment 00000000 .comment
00000000 l d .gnu.attributes 00000000 .gnu.attributes
00000000 g F .text 00000012 f
Disassembly of section .text:
00000000 <f>:
0: 6500 nop
2: 6500 nop
4: 6500 nop
6: 6491 save 8,s1
8: 673d move s1,sp
a: 6500 nop
c: 65b9 move sp,s1
e: 6411 restore 8,s1
10: e8a0 jrc ra
12: 6500 nop
14: 6500 nop
16: 6500 nop
18: 6500 nop
1a: 6500 nop
1c: 6500 nop
1e: 6500 nop
but， with b.c,
ambrosehua@3A1000-800M:~$ cat b.c
void f(float a, float b)
{
}
it is much more complicated.
ambrosehua@3A1000-800M:~$ gcc -fpatchable-function-entry=3 -mips16 -mabi=32
-c b.c -S -o b.1.s
ambrosehua@3A1000-800M:~$ cat b.1.s
.section .mdebug.abi32
.previous
.nan legacy
.module fp=xx
.module nooddspreg
.abicalls
.text
.align 2
.globl f
.set mips16
.set nomicromips
.ent f
.type f, @function
f:
.section __patchable_function_entries,"a",@progbits
.4byte $LPFE1
.text
$LPFE1:
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
# Stub function for f (float, float)
.section .mips16.fn.f,"ax",@progbits
.align 2
.set mips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.section __patchable_function_entries
.4byte $LPFE2
.section .mips16.fn.f
$LPFE2:
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set nomips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.set noreorder
.cpload $25
.set reorder
.reloc 0,R_MIPS_NONE,f
la $25,__fn_local_f
mfc1 $4,$f12
mfc1 $5,$f14
jr $25
.end __fn_stub_f
__fn_local_f = f
.text
.frame $17,8,$31 # vars= 0, regs= 1/0, args= 0, gp= 0
.mask 0x00020000,-4
.fmask 0x00000000,0
save 8,$17
move $17,$sp
sw $4,8($17)
sw $5,12($17)
.set noreorder
nop
.set reorder
move $sp,$17
restore 8,$17
jr $31
.end f
.size f, .-f
.ident "GCC: (Debian 8.3.0-8.lnd.4) 8.3.0"
for comparison， without -fpatchable-function-entry=3
ambrosehua@3A1000-800M:~$ gcc -mips16 -mabi=32 -c b.c -S -o b.2.s
ambrosehua@3A1000-800M:~$ cat b.2.s
.file 1 "b.c"
.section .mdebug.abi32
.previous
.nan legacy
.module fp=xx
.module nooddspreg
.abicalls
.text
.align 2
.globl f
.set mips16
.set nomicromips
.ent f
.type f, @function
f:
# Stub function for f (float, float)
.section .mips16.fn.f,"ax",@progbits
.align 2
.set mips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.set nomips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.set noreorder
.cpload $25
.set reorder
.reloc 0,R_MIPS_NONE,f
la $25,__fn_local_f
mfc1 $4,$f12
mfc1 $5,$f14
jr $25
.end __fn_stub_f
__fn_local_f = f
.text
.frame $17,8,$31 # vars= 0, regs= 1/0, args= 0, gp= 0
.mask 0x00020000,-4
.fmask 0x00000000,0
save 8,$17
move $17,$sp
sw $4,8($17)
sw $5,12($17)
.set noreorder
nop
.set reorder
move $sp,$17
restore 8,$17
jr $31
.end f
.size f, .-f
.ident "GCC: (Debian 8.3.0-8.lnd.4) 8.3.0"
with original gcc 8.3 in Debian10,
depaulose@3A1000-800M:/home/ambrosehua$ gcc -mabi=32 -c b.c -S -o b.3.s
-mips16
depaulose@3A1000-800M:/home/ambrosehua$ cat b.3.s
.file 1 "b.c"
.section .mdebug.abi32
.previous
.nan legacy
.module fp=xx
.module nooddspreg
.abicalls
.text
.align 2
.globl f
# Stub function for f (float, float)
.section .mips16.fn.f,"ax",@progbits
.align 2
.set nomips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.set noreorder
.cpload $25
.set reorder
.reloc 0,R_MIPS_NONE,f
la $25,__fn_local_f
mfc1 $4,$f12
mfc1 $5,$f14
jr $25
.end __fn_stub_f
__fn_local_f = f
.text
.set mips16
.set nomicromips
.ent f
.type f, @function
f:
.frame $17,8,$31 # vars= 0, regs= 1/0, args= 0, gp= 0
.mask 0x00020000,-4
.fmask 0x00000000,0
save 8,$17
move $17,$sp
sw $4,8($17)
sw $5,12($17)
.set noreorder
nop
.set reorder
move $sp,$17
restore 8,$17
jr $31
.end f
.size f, .-f
.ident "GCC: (Debian 8.3.0-6) 8.3.0"
I think there is somthing wrong here with handling stub for O32 MIPS16 floating
parameter.
+. Point 1, with b.3.s, the func entry should be __fn_stub_f instead of f,
which I mean the f in symbol table should point to the __fn_stub_f in the b.3.s
, and __fn_local_f in symbol table should point to the f in the b.3.s ;
+. Point 2, if Point 1 is right, the b.2.s should be just like Point 1, but it
is not right now, and we need fix this at first;
+. Point 3, if Point 1 is right, b.1.s should has only 3 nops in the mip32 32
stub code, instead of both in mips32 stub code and mip16 code.
Did I get it right?
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
` (4 preceding siblings ...)
2021-12-04 7:54 ` huangpei at loongson dot cn
@ 2021-12-15 10:00 ` huangpei at loongson dot cn
2021-12-15 10:01 ` huangpei at loongson dot cn
6 siblings, 0 replies; 8+ messages in thread
From: huangpei at loongson dot cn @ 2021-12-15 10:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
huangpei at loongson dot cn <huangpei at loongson dot cn> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |huangpei at loongson dot cn
--- Comment #6 from huangpei at loongson dot cn <huangpei at loongson dot cn> ---
Created attachment 52005
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52005&action=edit
fix -fpatch-function-entry on MIPS
Patch 0001 fix -fpatchable-function-entry on non-MIPS16, but it cause
compiling b.c (see previous comment) with duplicate __fn_stub_f* in asm output
in MIPS16
Patch 0002 remove the duplicate __fn_stub_f* by filter __fn_stub_ in
ASM_DECLARE_FUNCTION_NAME. However, implenmenting ASM_DECLARE_FUNCTION_NAME
cause asm generation of function f interleave with __fn_stub_f, which cause
error even without -fpatchable-function-entry on MIPS16. Patch 0002
separates asm generation of f from its stub by delay
"mips16_build_function_stub" till "mips_output_function_epilogue", and no error
on MIPS16 without -fpatchable-function-entry.
But it is not perfect.
+. without -fpatchable-function-entry, asm output of b.c like this
.file 1 "b.c"
.section .mdebug.abi32
.previous
.nan legacy
.module fp=32
.module oddspreg
.abicalls
.text
.align 2
.globl f
.set mips16
.set nomicromips
.ent f
.type f, @function
f:
.frame $17,8,$31 # vars= 0, regs= 1/0, args= 0, gp= 0
.mask 0x00020000,-4
.fmask 0x00000000,0
save 8,$17
move $17,$sp
sw $4,8($17)
sw $5,12($17)
.set noreorder
nop
.set reorder
move $sp,$17
restore 8,$17
jr $31
.end f
!!!! .size f, .-f should be here
# Stub function for f (float, float)
.section .mips16.fn.f,"ax",@progbits
.align 2
.set nomips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.set noreorder
.cpload $25
.set reorder
.reloc 0,R_MIPS_NONE,f
la $25,__fn_local_f
mfc1 $4,$f12
mfc1 $5,$f14
jr $25
.end __fn_stub_f
__fn_local_f = f
.text
.size f, .-f !!! .size should be not be here
.ident "GCC: (GNU) 8.3.0"
+. with -fpatchable-functione-entry=3, asm output of b.c like this,
.section .mdebug.abi32
.previous
.nan legacy
.module fp=32
.module oddspreg
.abicalls
.text
.align 2
.globl f
.set mips16
.set nomicromips
.ent f
.type f, @function
f:
.section __patchable_function_entries,"a",@progbits
.4byte $LPFE1
.text
!!! f should not be patched with nop, since this is the first entry from
caller's point
$LPFE1:
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.frame $17,8,$31 # vars= 0, regs= 1/0, args= 0, gp= 0
.mask 0x00020000,-4
.fmask 0x00000000,0
save 8,$17
move $17,$sp
sw $4,8($17)
sw $5,12($17)
.set noreorder
nop
.set reorder
move $sp,$17
restore 8,$17
jr $31
.end f
# Stub function for f (float, float)
.section .mips16.fn.f,"ax",@progbits
.align 2
.section __patchable_function_entries
.4byte $LPFE2
.section .mips16.fn.f
$LPFE2:
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set noreorder
nop
.set reorder
.set nomips16
.set nomicromips
.ent __fn_stub_f
.type __fn_stub_f, @function
__fn_stub_f:
.set noreorder
.cpload $25
.set reorder
.reloc 0,R_MIPS_NONE,f
la $25,__fn_local_f
mfc1 $4,$f12
mfc1 $5,$f14
jr $25
.end __fn_stub_f
__fn_local_f = f
.text
.size f, .-f
.ident "GCC: (GNU) 8.3.0"
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug target/99217] [MIPS] wrong function entry with -fpatchable-function-entry
2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
` (5 preceding siblings ...)
2021-12-15 10:00 ` huangpei at loongson dot cn
@ 2021-12-15 10:01 ` huangpei at loongson dot cn
6 siblings, 0 replies; 8+ messages in thread
From: huangpei at loongson dot cn @ 2021-12-15 10:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99217
--- Comment #7 from huangpei at loongson dot cn <huangpei at loongson dot cn> ---
Created attachment 52006
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52006&action=edit
patch 0001
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-12-15 10:01 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2021-02-23 11:37 [Bug c/99217] New: [MIPS] wrong function entry with -fpatchable-function-entry huangpei at loongson dot cn
2021-02-23 19:44 ` [Bug target/99217] " pinskia at gcc dot gnu.org
2021-03-04 2:07 ` huangpei at loongson dot cn
2021-03-04 3:20 ` pinskia at gcc dot gnu.org
2021-03-05 7:22 ` huangpei at loongson dot cn
2021-12-04 7:54 ` huangpei at loongson dot cn
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