Fix initializing members multiple times

When intializing members where the initializer needs relocations
and the member is initialized multiple times we can't allow
that to lead to multiple relocations to the same place.  The last
one must win.

1 files changed, 37 insertions, 0 deletions

diff --git a/tccelf.c b/tccelf.c
index c97d742..003797c 100644
--- a/tccelf.c
+++ b/tccelf.c
@@ -535,6 +535,43 @@ ST_FUNC void put_elf_reloc(Section *symtab, Section *s, unsigned long offset,
     put_elf_reloca(symtab, s, offset, type, symbol, 0);
 }
 
+/* Remove relocations for section S->reloc starting at oldrelocoffset
+   that are to the same place, retaining the last of them.  As side effect
+   the relocations are sorted.  Possibly reduces the number of relocs.  */
+ST_FUNC void squeeze_multi_relocs(Section *s, size_t oldrelocoffset)
+{
+    Section *sr = s->reloc;
+    ElfW_Rel *r, *dest;
+    ssize_t a;
+    ElfW(Addr) addr;
+
+    if (oldrelocoffset + sizeof(*r) >= sr->data_offset)
+      return;
+    /* The relocs we're dealing with are the result of initializer parsing.
+       So they will be mostly in order and there aren't many of them.
+       Secondly we need a stable sort (which qsort isn't).  We use
+       a simple insertion sort.  */
+    for (a = oldrelocoffset + sizeof(*r); a < sr->data_offset; a += sizeof(*r)) {
+	ssize_t i = a - sizeof(*r);
+	addr = ((ElfW_Rel*)(sr->data + a))->r_offset;
+	for (; i >= (ssize_t)oldrelocoffset &&
+	       ((ElfW_Rel*)(sr->data + i))->r_offset > addr; i -= sizeof(*r)) {
+	    ElfW_Rel tmp = *(ElfW_Rel*)(sr->data + a);
+	    *(ElfW_Rel*)(sr->data + a) = *(ElfW_Rel*)(sr->data + i);
+	    *(ElfW_Rel*)(sr->data + i) = tmp;
+	}
+    }
+
+    r = (ElfW_Rel*)(sr->data + oldrelocoffset);
+    dest = r;
+    for (; r < (ElfW_Rel*)(sr->data + sr->data_offset); r++) {
+	if (dest->r_offset != r->r_offset)
+	  dest++;
+	*dest = *r;
+    }
+    sr->data_offset = (unsigned char*)dest - sr->data + sizeof(*r);
+}
+
 /* put stab debug information */
 
 ST_FUNC void put_stabs(const char *str, int type, int other, int desc,