[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 Martin Decky changed: What|Removed |Added Version|4.6.0 |4.6.1 --- Comment #1 from Martin Decky 2011-06-29 15:01:46 UTC --- The bug is still present in GCC 4.6.1.
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 --- Comment #2 from Martin Decky 2011-06-30 16:03:08 UTC --- Created attachment 24646 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24646 Initial proposed patch The attached patch works as a temporary workaround and might also hint where exactly the problem is. Now, guys, please don't crucify me for this patch. I am well aware that this patch is no more than a dirty hack and probably breaks other thinks. I present it here only to provoke some reaction from somebody who knows GCC sources well enough to propose a real solution. I have just spent some 4 hours browsing the sources, analysing relevant functions such as output_asm_insn(), ix86_print_operand(), print_reg() and similar to figure out how to change the way the tail call instruction is generated for this particular case. But I would really appreciate a little help from a senior GCC developer who not only knows what and how, but also why. Thanks in advance!
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 H.J. Lu changed: What|Removed |Added Status|UNCONFIRMED |WAITING Last reconfirmed||2011.06.30 22:59:32 CC||hjl.tools at gmail dot com Ever Confirmed|0 |1 --- Comment #3 from H.J. Lu 2011-06-30 22:59:32 UTC --- Please provide a small testcase.
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 H.J. Lu changed: What|Removed |Added Status|WAITING |NEW --- Comment #4 from H.J. Lu 2011-06-30 23:01:37 UTC --- Confirmed.
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385
--- Comment #5 from H.J. Lu 2011-06-30 23:11:09
UTC ---
[hjl@gnu-33 delta]$ cat testcase.c
typedef unsigned char uint8_t;
typedef unsigned long int uint64_t;
typedef uint64_t size_t;
typedef uint64_t uintptr_t;
typedef uint8_t bool;
typedef struct {
unsigned int unused:
1;
unsigned int addr_12_31 : 30;
unsigned int addr_32_51 : 21;
} __attribute__ ((packed)) pte_t;
typedef struct {
pte_t *page_table;
} as_genarch_t;
typedef struct as {
as_genarch_t genarch;
} as_t;
void pt_mapping_remove(as_t *as, uintptr_t page) {
pte_t *ptl0 = (pte_t *) (((uintptr_t) ((uintptr_t) as->genarch.page_table)) +
0x8000UL);
pte_t *ptl1 = (pte_t *) (((uintptr_t) (((pte_t *) uint64_t) ((pte_t *)
(ptl0))[page) >> 39) & 0x1ffU))].addr_12_31) << 12) | (((uint64_t) ((pte_t
*) (ptl0))[page) >> 39) & 0x1ffU))].addr_32_51) << 32) +
0x8000UL);
pte_t *ptl2 = (pte_t *) (((uintptr_t) (((pte_t *) uint64_t) ((pte_t *)
(ptl1))[page) >> 30) & 0x1ffU))].addr_12_31) << 12) | (((uint64_t) ((pte_t
*) (ptl1))[page) >> 30) & 0x1ffU))].addr_32_51) << 32) +
0x8000UL);
pte_t *ptl3 = (pte_t *) (((uintptr_t) (((pte_t *) uint64_t) ((pte_t *)
(ptl2))[page) >> 21) & 0x1ffU))].addr_12_31) << 12) | (((uint64_t) ((pte_t
*) (ptl2))[page) >> 21) & 0x1ffU))].addr_32_51) << 32) +
0x8000UL);
memsetb(&ptl3[(((page) >> 12) & 0x1ffU)], sizeof(pte_t), 0);
bool empty = 1;
unsigned int i;
for (i = 0;
i < 512;
i++) {
if ((*((uint64_t *) ((&ptl3[i]))) != 0)) {
empty = 0;
}
}
for (i = 0;
i < 512;
i++) {
if ((*((uint64_t *) ((&ptl2[i]))) != 0)) {
empty = 0;
}
}
if (empty) {
frame_freeuintptr_t) ((uintptr_t) ptl1)) - 0x8000UL));
memsetb(&ptl0[(((page) >> 39) & 0x1ffU)], sizeof(pte_t), 0);
}
}
[hjl@gnu-33 delta]$
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 --- Comment #6 from Martin Decky 2011-07-01 02:53:18 UTC --- Created attachment 24650 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24650 Short test case Thanks, H.J. Lu, for providing the short test case. I have just added three extern declarations to make it compile in my freestanding setup and I confirm that it demonstrates the bug in my environment. I'll post the save-temps output shortly.
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385
Martin Decky changed:
What|Removed |Added
Attachment #23836|0 |1
is obsolete||
--- Comment #7 from Martin Decky 2011-07-01 02:57:21
UTC ---
Created attachment 24651
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24651
Preprocessed file for the short test case
Output of /usr/local/cross/amd64/bin/amd64-linux-gnu-gcc -v:
Using built-in specs.
COLLECT_GCC=/usr/local/cross/amd64/bin/amd64-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/usr/local/cross/amd64/libexec/gcc/amd64-linux-gnu/4.6.1/lto-wrapper
Target: amd64-linux-gnu
Configured with: /root/install/cross/amd64/gcc-4.6.1/configure
--target=amd64-linux-gnu --prefix=/usr/local/cross/amd64
--program-prefix=amd64-linux-gnu- --with-gnu-as --with-gnu-ld --disable-nls
--disable-threads --enable-languages=c,objc,c++,obj-c++ --disable-multilib
--disable-libgcj --without-headers --disable-shared --enable-lto
Thread model: single
gcc version 4.6.1 (GCC)
Command line that triggered the bug:
/usr/local/cross/amd64/bin/amd64-linux-gnu-gcc -DKERNEL -DRELEASE=0.4.3
"-DNAME=Sashimi" -D__64_BITS__ -D__LE__ -Igeneric/include -O3 -imacros
../config.h -fexec-charset=UTF-8 -fwide-exec-charset=UTF-32LE
-finput-charset=UTF-8 -ffreestanding -fno-builtin -nostdlib -nostdinc
-std=gnu99 -Wall -Wextra -Wno-unused-parameter -Wmissing-prototypes
-Werror-implicit-function-declaration -Wwrite-strings -pipe -Werror -m64
-mcmodel=large -mno-red-zone -fno-unwind-tables -fno-omit-frame-pointer
-march=opteron -Itest/ -mno-sse -mno-sse2 -c -o genarch/src/mm/page_pt.o
genarch/src/mm/page_pt.c
Compiler output:
{standard input}: Assembler messages:
{standard input}:284: Error: immediate operand illegal with absolute jump
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 --- Comment #8 from Mikael Pettersson 2012-11-07 19:47:58 UTC --- This was fixed for gcc-4.6.2 in r176841, the 4.6 fix for the essentially identical issue reported as PR49866. The generated assembly for the test case in comment #7 changed as follows in r176841: --- pr48385.s-r176840 2012-11-07 20:33:29.0 +0100 +++ pr48385.s-r176841 2012-11-07 20:37:54.0 +0100 @@ -205,7 +205,8 @@ popq%r15 .cfi_def_cfa_offset 8 movl$7, %esi - jmp *$memsetb + movabsq $memsetb, %rax + jmp *%rax .cfi_endproc .LFE0: .size pt_mapping_remove, .-pt_mapping_remove The test case also works fine with gcc-4.7.2 (contrary to what the known-to-fail line states). I think this should be closed as a duplicate of PR49886.
[Bug target/48385] x86-64: Tail call recursion optimization with -mcmodel=large can generate invalid assembly (immediate operand illegal with absolute jump)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 Martin Decky changed: What|Removed |Added Status|NEW |RESOLVED Resolution||FIXED Known to fail|4.7.2, 4.8.0| --- Comment #9 from Martin Decky 2012-11-08 10:24:06 UTC --- I can confirm that the bug is no longer present in 4.7.2, as noted in comment #8. Therefore I am closing this bug as resolved/fixed. I am not marking it as duplicate of 49866 since this bug was reported earlier and to a different version (but feel free to change this). Thanks for fixing this!
