Only create GOT or GOT entry when needed

Currently we always build a GOT when we recognize a relocation in
build_got_entries even if the relocation does not require one. In the
same spirit, when the relocation does require one we always create a GOT
entry even if not entry is necessary. This patch restricts the creation
of a GOT and a GOT entry to relocations that needs it, ie:
- do not create a GOT if relocation is not related to GOT and symbol is
  not UNDEF
- do not create a GOT entry if relocation only relates to beginning of
  GOT

1 files changed, 27 insertions, 22 deletions

diff --git a/tccelf.c b/tccelf.c
index e0eaea5..63e8111 100644
--- a/tccelf.c
+++ b/tccelf.c
@@ -1032,6 +1032,8 @@ ST_FUNC void build_got_entries(TCCState *s1)
             continue;
         for_each_elem(s, 0, rel, ElfW_Rel) {
             type = ELFW(R_TYPE)(rel->r_info);
+            sym_index = ELFW(R_SYM)(rel->r_info);
+            sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
             switch(type) {
 #if defined(TCC_TARGET_I386)
             case R_386_PC16:
@@ -1041,15 +1043,17 @@ ST_FUNC void build_got_entries(TCCState *s1)
             case R_386_GOTOFF:
             case R_386_GOTPC:
             case R_386_PLT32:
+                if (sym->st_shndx != SHN_UNDEF && type != R_386_GOT32 &&
+                    type != R_386_GOT32X && type != R_386_GOTOFF &&
+                    type != R_386_GOTPC && type != R_386_PLT32)
+                    break;
+
                 if (!s1->got)
                     build_got(s1);
-                if (type == R_386_GOT32 || type == R_386_GOT32X ||
-                    type == R_386_PLT32) {
-                    sym_index = ELFW(R_SYM)(rel->r_info);
-                    sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
+
+                if (type != R_386_GOTOFF && type != R_386_GOTPC) {
                     /* look at the symbol got offset. If none, then add one */
-                    if (type == R_386_GOT32 || type == R_386_GOT32X ||
-                        type == R_386_16 || type == R_386_32)
+                    if (type == R_386_GOT32 || type == R_386_GOT32X)
                         reloc_type = R_386_GLOB_DAT;
                     else
                         reloc_type = R_386_JMP_SLOT;
@@ -1073,11 +1077,13 @@ ST_FUNC void build_got_entries(TCCState *s1)
             case R_ARM_GOTOFF:
             case R_ARM_GOT32:
             case R_ARM_V4BX:
+                if (sym->st_shndx != SHN_UNDEF && type != R_ARM_GOT32 &&
+                    type != R_ARM_GOTOFF && type != R_ARM_GOTPC &&
+                    type != R_ARM_PLT32)
+                    break;
 
                 if (!s1->got)
                     build_got(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
                         || s1->output_type == TCC_OUTPUT_MEMORY)) {
@@ -1206,22 +1212,21 @@ ST_FUNC void build_got_entries(TCCState *s1)
             case R_X86_64_PLT32:
                 sym_index = ELFW(R_SYM)(rel->r_info);
                 sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
-		if (type == R_X86_64_PLT32 &&
-		    ELFW(ST_VISIBILITY)(sym->st_other) != STV_DEFAULT)
-		  {
-		    rel->r_info = ELFW(R_INFO)(sym_index, R_X86_64_PC32);
-		    break;
-		  }
+                if ((type == R_X86_64_32 || type == R_X86_64_32S ||
+                     type == R_X86_64_64 || type == R_X86_64_PC32) &&
+                    sym->st_shndx != SHN_UNDEF)
+                    break;
 
-                if (!s1->got) {
-                    build_got(s1);
-                    sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
+                if (type == R_X86_64_PLT32 &&
+                    ELFW(ST_VISIBILITY)(sym->st_other) != STV_DEFAULT) {
+                    rel->r_info = ELFW(R_INFO)(sym_index, R_X86_64_PC32);
+                    break;
                 }
-                if (type == R_X86_64_GOT32 || type == R_X86_64_GOTPCREL ||
-		    type == R_X86_64_GOTPCRELX ||
-		    type == R_X86_64_REX_GOTPCRELX ||
-                    type == R_X86_64_PLT32) {
-		    unsigned long ofs;
+
+                if (!s1->got)
+                    build_got(s1);
+                if (type != R_X86_64_GOTTPOFF) {
+                    unsigned long ofs;
                     /* look at the symbol got offset. If none, then add one */
                     if (type == R_X86_64_GOT32 || type == R_X86_64_GOTPCREL ||
                         type == R_X86_64_GOTPCRELX ||