OSO/TinyCC
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix stack overwrite on structure return

Browse Source 
The common code to move a returned structure packed into
registers into memory on the caller side didn't take the
register size into account when allocating local storage,
so sometimes that lead to stack overwrites (e.g. in 73_arm64.c),
on x86_64.  This fixes it by generally making gfunc_sret also return
the register size.
This commit is contained in:
Michael Matz
2015-03-09 00:19:59 +01:00
parent d73b488401
commit 50899e30ab
7 changed files with 26 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
x86_64-gen.c
View File

@ -662,9 +662,10 @@ void gen_offs_sp(int b, int r, int d)
/* Return the number of registers needed to return the struct, or 0 if
returning via struct pointer. */
ST_FUNC int gfunc_sret(CType *vt, int variadic, CType *ret, int *ret_align)
ST_FUNC int gfunc_sret(CType *vt, int variadic, CType *ret, int *ret_align, int *regsize)
{
int size, align;
*regsize = 8;
*ret_align = 1; // Never have to re-align return values for x86-64
size = type_size(vt, &align);
ret->ref = NULL;
@ -1069,10 +1070,11 @@ ST_FUNC int classify_x86_64_va_arg(CType *ty)
/* Return the number of registers needed to return the struct, or 0 if
returning via struct pointer. */
ST_FUNC int gfunc_sret(CType *vt, int variadic, CType *ret, int *ret_align)
ST_FUNC int gfunc_sret(CType *vt, int variadic, CType *ret, int *ret_align, int *regsize)
{
int size, align, reg_count;
*ret_align = 1; // Never have to re-align return values for x86-64
*regsize = 8;
return (classify_x86_64_arg(vt, ret, &size, &align, &reg_count) != x86_64_mode_memory);
}