From 8833dcbcb071f44dcb06871b0b0a0640028eb58e Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@cs.stanford.edu>
Date: Mon, 7 Jun 2021 15:24:03 +0900
Subject: [PATCH] Fix relocations for i386 PIC

---
 arch_i386.cc        | 32 ++++++++++++++++----------------
 test/i386-shared.sh | 45 +++++++++++++++++++++++++++++++++++++++++++++
 test/i386-tls-gd.sh |  4 ++--
 test/tls-gd.sh      |  4 ++--
 4 files changed, 65 insertions(+), 20 deletions(-)
 create mode 100755 test/i386-shared.sh

diff --git a/arch_i386.cc b/arch_i386.cc
index 608d9586..b3743681 100644
--- a/arch_i386.cc
+++ b/arch_i386.cc
@@ -47,7 +47,7 @@ void PltSection<I386>::copy_buf(Context<I386> &ctx) {
         0xe9, 0,    0, 0, 0,    // jmp .PLT0@PC
       };
       memcpy(ent, data, sizeof(data));
-      *(u32 *)(ent + 2) = sym->get_gotplt_addr(ctx) - ctx.got->shdr.sh_addr;
+      *(u32 *)(ent + 2) = sym->get_gotplt_addr(ctx) - ctx.gotplt->shdr.sh_addr;
     } else {
       static const u8 data[] = {
         0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOT
@@ -76,7 +76,7 @@ void PltGotSection<I386>::copy_buf(Context<I386> &ctx) {
     for (i64 i = 0; i < symbols.size(); i++) {
       u8 *ent = buf + i * sizeof(data);
       memcpy(ent, data, sizeof(data));
-      *(u32 *)(ent + 2) = symbols[i]->get_got_addr(ctx) - ctx.got->shdr.sh_addr;
+      *(u32 *)(ent + 2) = symbols[i]->get_got_addr(ctx) - ctx.gotplt->shdr.sh_addr;
     }
   } else {
     static const u8 data[] = {
@@ -164,11 +164,11 @@ void InputSection<I386>::apply_reloc_alloc(Context<I386> &ctx, u8 *base) {
       write_val(ctx, rel.r_type, loc, val);
     };
 
-#define S   (ref ? ref->frag->get_addr(ctx) : sym.get_addr(ctx))
-#define A   (ref ? ref->addend : 0)
-#define P   (output_section->shdr.sh_addr + offset + rel.r_offset)
-#define G   (sym.get_got_addr(ctx) - ctx.got->shdr.sh_addr)
-#define GOT ctx.got->shdr.sh_addr
+#define S      (ref ? ref->frag->get_addr(ctx) : sym.get_addr(ctx))
+#define A      (ref ? ref->addend : 0)
+#define P      (output_section->shdr.sh_addr + offset + rel.r_offset)
+#define G      (sym.get_got_addr(ctx) - ctx.got->shdr.sh_addr)
+#define GOTPLT ctx.gotplt->shdr.sh_addr
 
     switch (rel_types[i]) {
     case R_NONE:
@@ -188,34 +188,34 @@ void InputSection<I386>::apply_reloc_alloc(Context<I386> &ctx, u8 *base) {
       write(S + A - P);
       break;
     case R_GOT:
-      write(G + A);
+      write(sym.get_got_addr(ctx) + A - GOTPLT);
       break;
     case R_GOTOFF:
-      write(S + A - GOT);
+      write(S + A - GOTPLT);
       break;
     case R_GOTPC:
-      write(GOT + A - P);
+      write(GOTPLT + A - P);
       break;
     case R_GOTPCREL:
-      write(G + GOT + A - P);
+      write(G + GOTPLT + A - P);
       break;
     case R_TLS_GOTIE:
-      write(sym.get_gottp_addr(ctx) + A - GOT);
+      write(sym.get_gottp_addr(ctx) + A - GOTPLT);
       break;
     case R_TLS_LE:
       write(S + A - ctx.tls_end);
       break;
     case R_TLS_GD:
-      write(sym.get_tlsgd_addr(ctx) + A - GOT);
+      write(sym.get_tlsgd_addr(ctx) + A - GOTPLT);
       break;
     case R_TLS_LD:
-      write(ctx.got->get_tlsld_addr(ctx) + A - GOT);
+      write(ctx.got->get_tlsld_addr(ctx) + A - GOTPLT);
       break;
     case R_TPOFF:
       write(S + A - ctx.tls_begin);
       break;
     case R_TLS_GOTDESC:
-      write(sym.get_tlsdesc_addr(ctx) + A - GOT);
+      write(sym.get_tlsdesc_addr(ctx) + A - GOTPLT);
       break;
     case R_TLS_GOTDESC_RELAX: {
       static const u8 insn[] = {
@@ -241,7 +241,7 @@ void InputSection<I386>::apply_reloc_alloc(Context<I386> &ctx, u8 *base) {
 #undef A
 #undef P
 #undef G
-#undef GOT
+#undef GOTPLT
   }
 }
 
diff --git a/test/i386-shared.sh b/test/i386-shared.sh
new file mode 100755
index 00000000..663f4819
--- /dev/null
+++ b/test/i386-shared.sh
@@ -0,0 +1,45 @@
+#!/bin/bash
+set -e
+cd $(dirname $0)
+echo -n "Testing $(basename -s .sh $0) ... "
+t=$(pwd)/tmp/$(basename -s .sh $0)
+mkdir -p $t
+
+cat <<EOF | clang -fPIC -c -o $t/a.o -xc - -m32
+int foo = 5;
+void set_foo(int x) { foo = x; }
+int get_foo() { return foo; }
+
+static int bar = 7;
+void set_bar(int x) { bar = x; }
+int get_bar() { return bar; }
+EOF
+
+clang -fuse-ld=`pwd`/../mold -o $t/b.so -shared $t/a.o -m32
+
+cat <<EOF > $t/c.c
+#include <stdio.h>
+
+int get_foo();
+int get_bar();
+
+int baz = 2;
+
+int main() {
+  printf("%d %d %d\n", get_foo(), get_bar(), baz);
+}
+EOF
+
+clang -c -o $t/d.o $t/c.c -fno-PIC -m32
+clang -fuse-ld=`pwd`/../mold -o $t/exe $t/d.o $t/b.so -m32
+$t/exe | grep -q '5 7 2'
+
+clang -c -o $t/e.o $t/c.c -fPIE -m32
+clang -fuse-ld=`pwd`/../mold -o $t/exe $t/e.o $t/b.so -m32
+$t/exe | grep -q '5 7 2'
+
+clang -c -o $t/f.o $t/c.c -fPIC -m32
+clang -fuse-ld=`pwd`/../mold -o $t/exe $t/f.o $t/b.so -m32
+$t/exe | grep -q '5 7 2'
+
+echo OK
diff --git a/test/i386-tls-gd.sh b/test/i386-tls-gd.sh
index 22210ecf..47780cc3 100755
--- a/test/i386-tls-gd.sh
+++ b/test/i386-tls-gd.sh
@@ -36,8 +36,8 @@ static _Thread_local int x6 = 6;
 int get_x6() { return x6; }
 EOF
 
-clang -shared -o $t/d.so $t/b.o -m32
-clang -shared -o $t/e.so $t/c.o -Wl,--no-relax -m32
+clang -fuse-ld=`pwd`/../mold -shared -o $t/d.so $t/b.o -m32
+clang -fuse-ld=`pwd`/../mold -shared -o $t/e.so $t/c.o -Wl,--no-relax -m32
 
 clang -fuse-ld=`pwd`/../mold -o $t/exe $t/a.o $t/d.so $t/e.so -m32
 $t/exe | grep -q '1 2 3 4 5 6'
diff --git a/test/tls-gd.sh b/test/tls-gd.sh
index a3e442be..8665392a 100755
--- a/test/tls-gd.sh
+++ b/test/tls-gd.sh
@@ -36,8 +36,8 @@ static _Thread_local int x6 = 6;
 int get_x6() { return x6; }
 EOF
 
-clang -shared -o $t/d.so $t/b.o
-clang -shared -o $t/e.so $t/c.o -Wl,--no-relax
+clang -fuse-ld=`pwd`/../mold -shared -o $t/d.so $t/b.o
+clang -fuse-ld=`pwd`/../mold -shared -o $t/e.so $t/c.o -Wl,--no-relax
 
 clang -fuse-ld=`pwd`/../mold -o $t/exe $t/a.o $t/d.so $t/e.so
 $t/exe | grep -q '1 2 3 4 5 6'