Re: [Tinycc-devel] RUNTIME_PLTGOT question

[Michael Matz]

Hello,

On Mon, 7 Nov 2016, Thomas Stalder wrote:

> I have tested with latests TinyCC git commit and sometimes i have the error
> (with DEBUG_RELOC) :
> 
> reloc 1: x=0xfffffe val=0x1eddc  newx=0xfdaf7d70 name=printf
> tcc: error: can't relocate value at 2527064,1

Out of range jump because no PLT is used for defined symbols, which can be 
a problem when compiling to memory and running from there when the 
compiled code calls functions defined in the executable itself but the 
code buffer is allocated too far away from those definitions.  I fixed a 
similar problem for aarch64 in 682ecc17, probably arm needs something 
similar.  Untested patch below, which possibly works around this, please 
try.


Ciao,
Michael.

diff --git a/tccelf.c b/tccelf.c
index 1e05bfb..a027700 100644
--- a/tccelf.c
+++ b/tccelf.c
@@ -828,7 +828,8 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
             {
                 int x, is_thumb, is_call, h, blx_avail, is_bl, th_ko;
                 x = (*(int *) ptr) & 0xffffff;
-               if (sym->st_shndx == SHN_UNDEF)
+               if (sym->st_shndx == SHN_UNDEF
+                   || s1->output_type == TCC_OUTPUT_MEMORY)
                    val = s1->plt->sh_addr;
 #ifdef DEBUG_RELOC
                printf ("reloc %d: x=0x%x val=0x%x ", type, x, val);
@@ -1578,7 +1579,8 @@ ST_FUNC void build_got_entries(TCCState *s1)
                 sym_index = ELFW(R_SYM)(rel->r_info);
                 sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
                if (type != R_ARM_GOTOFF && type != R_ARM_GOTPC
-                   && sym->st_shndx == SHN_UNDEF) {
+                   && (sym->st_shndx == SHN_UNDEF
+                       || s1->output_type == TCC_OUTPUT_MEMORY)) {
                     unsigned long ofs;
                     /* look at the symbol got offset. If none, then add one */
                     if (type == R_ARM_GOT32)