d0p1/tcc-stupidos
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int main()

Browse source 
{
	struct st {
		int aa:16;
		int bb:16;
	} s;
	s.aa = 1;
	s.bb = 2;
	return 0;
}
objdump -d:
elf64-x86-64
Disassembly of section .text:

0000000000000000 <main>:
   0:	55                   	push   %rbp
   1:	48 89 e5             	mov    %rsp,%rbp
   4:	48 81 ec 10 00 00 00 	sub    $0x10,%rsp
   b:	b8 01 00 00 00       	mov    $0x1,%eax
  10:	48 89 c1             	mov    %rax,%rcx
  13:	81 e1 ff ff 00 00    	and    $0xffff,%ecx
  19:	8b 55 fc             	mov    -0x4(%rbp),%edx
  1c:	81 e2 00 00 ff ff    	and    $0xffff0000,%edx
  22:	09 d1                	or     %edx,%ecx
  24:	89 4d fc             	mov    %ecx,-0x4(%rbp)
  27:	b8 02 00 00 00       	mov    $0x2,%eax
  2c:	48 89 c1             	mov    %rax,%rcx
  2f:	81 e1 ff ff 00 00    	and    $0xffff,%ecx
  35:	c1 e1 10             	shl    $0x10,%ecx
  38:	8b 55 fc             	mov    -0x4(%rbp),%edx
  3b:	81 e2 ff ff 00 00    	and    $0xffff,%edx
  41:	09 d1                	or     %edx,%ecx
  43:	89 4d fc             	mov    %ecx,-0x4(%rbp)
  46:	b8 00 00 00 00       	mov    $0x0,%eax
  4b:	e9 00 00 00 00       	jmpq   50 <main+0x50>
  50:	c9                   	leaveq
  51:	c3                   	retq

After the patch

Disassembly of section .text:

0000000000000000 <main>:
   0:	55                   	push   %rbp
   1:	48 89 e5             	mov    %rsp,%rbp
   4:	48 81 ec 10 00 00 00 	sub    $0x10,%rsp
   b:	8b 45 fc             	mov    -0x4(%rbp),%eax
   e:	81 e0 00 00 ff ff    	and    $0xffff0000,%eax
  14:	83 c8 01             	or     $0x1,%eax
  17:	89 45 fc             	mov    %eax,-0x4(%rbp)
  1a:	8b 45 fc             	mov    -0x4(%rbp),%eax
  1d:	81 e0 ff ff 00 00    	and    $0xffff,%eax
  23:	81 c8 00 00 02 00    	or     $0x20000,%eax
  29:	89 45 fc             	mov    %eax,-0x4(%rbp)
  2c:	b8 00 00 00 00       	mov    $0x0,%eax
  31:	e9 00 00 00 00       	jmpq   36 <main+0x36>
  36:	c9                   	leaveq
  37:	c3                   	retq
This commit is contained in:
jiang 2014-05-17 12:32:00 +08:00
parent a94ed43094
commit e5e7f488e2
1 changed files with 10 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
tccgen.c
View file

@ -1019,6 +1019,7 @@ ST_FUNC void lexpand_nr(void)
}
#endif
#ifndef TCC_TARGET_X86_64
/* build a long long from two ints */
static void lbuild(int t)
{
@ -1027,6 +1028,7 @@ static void lbuild(int t)
vtop[-1].type.t = t;
vpop();
}
#endif
/* rotate n first stack elements to the bottom
I1 ... In -> I2 ... In I1 [top is right]
@ -1088,8 +1090,8 @@ static void gv_dup(void)
{
int rc, t, r, r1;
SValue sv;
t = vtop->type.t;
#ifndef TCC_TARGET_X86_64
if ((t & VT_BTYPE) == VT_LLONG) {
lexpand();
gv_dup();
@ -1099,15 +1101,14 @@ static void gv_dup(void)
vrotb(4);
/* stack: H L L1 H1 */
lbuild(t);
vrotb(3);
vrotb(3);
vrott(3);
vswap();
lbuild(t);
vswap();
} else {
} else
#endif
{
/* duplicate value */
rc = RC_INT;
sv.type.t = VT_INT;
if (is_float(t)) {
rc = RC_FLOAT;
#ifdef TCC_TARGET_X86_64
@ -1115,8 +1116,9 @@ static void gv_dup(void)
rc = RC_ST0;
}
#endif
sv.type.t = t;
}
}else
rc = RC_INT;
sv.type.t = t;
r = gv(rc);
r1 = get_reg(rc);
sv.r = r;
@ -2549,11 +2551,6 @@ ST_FUNC void vstore(void)
/* remove bit field info to avoid loops */
vtop[-1].type.t = ft & ~(VT_BITFIELD | (-1 << VT_STRUCT_SHIFT));
/* duplicate source into other register */
gv_dup();
vswap();
vrott(3);
if((ft & VT_BTYPE) == VT_BOOL) {
gen_cast(&vtop[-1].type);
vtop[-1].type.t = (vtop[-1].type.t & ~VT_BTYPE) | (VT_BYTE | VT_UNSIGNED);
@ -2585,10 +2582,6 @@ ST_FUNC void vstore(void)
gen_op('|');
/* store result */
vstore();
/* pop off shifted source from "duplicate source..." above */
vpop();
} else {
#ifdef CONFIG_TCC_BCHECK
/* bound check case */