From cb273fdad891d312c15110cd4eab95f5db39dcb2 Mon Sep 17 00:00:00 2001
From: Thomas Preud'homme <robotux@celest.fr>
Date: Sat, 12 Nov 2016 23:16:06 +0800
Subject: Do section relocation in architecture backend

---
 x86_64-link.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 x86_64-link.c

(limited to 'x86_64-link.c')

diff --git a/x86_64-link.c b/x86_64-link.c
new file mode 100644
index 0000000..2a9e9b0
--- /dev/null
+++ b/x86_64-link.c
@@ -0,0 +1,99 @@
+#include "tcc.h"
+#define HAVE_SECTION_RELOC
+
+static ElfW_Rel *qrel; /* ptr to next reloc entry reused */
+
+void relocate_init(Section *sr)
+{
+    qrel = (ElfW_Rel *) sr->data;
+}
+
+void relocate(TCCState *s1, ElfW_Rel *rel, int type, char *ptr, addr_t addr, addr_t val)
+{
+    int sym_index, esym_index;
+
+    sym_index = ELFW(R_SYM)(rel->r_info);
+
+    switch (type) {
+        case R_X86_64_64:
+            if (s1->output_type == TCC_OUTPUT_DLL) {
+                esym_index = s1->symtab_to_dynsym[sym_index];
+                qrel->r_offset = rel->r_offset;
+                if (esym_index) {
+                    qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_64);
+		    qrel->r_addend = rel->r_addend;
+                    qrel++;
+                    break;
+                } else {
+		    qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
+		    qrel->r_addend = read64le(ptr) + val;
+                    qrel++;
+                }
+            }
+            add64le(ptr, val);
+            break;
+        case R_X86_64_32:
+        case R_X86_64_32S:
+            if (s1->output_type == TCC_OUTPUT_DLL) {
+                /* XXX: this logic may depend on TCC's codegen
+                   now TCC uses R_X86_64_32 even for a 64bit pointer */
+                qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
+                /* Use sign extension! */
+                qrel->r_addend = (int)read32le(ptr) + val;
+                qrel++;
+            }
+            add32le(ptr, val);
+            break;
+
+        case R_X86_64_PC32:
+            if (s1->output_type == TCC_OUTPUT_DLL) {
+                /* DLL relocation */
+                esym_index = s1->symtab_to_dynsym[sym_index];
+                if (esym_index) {
+                    qrel->r_offset = rel->r_offset;
+                    qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC32);
+                    /* Use sign extension! */
+                    qrel->r_addend = (int)read32le(ptr) + rel->r_addend;
+                    qrel++;
+                    break;
+                }
+            }
+            goto plt32pc32;
+
+        case R_X86_64_PLT32:
+	    /* We've put the PLT slot offset into r_addend when generating
+	       it, and that's what we must use as relocation value (adjusted
+	       by section offset of course).  */
+	    val = s1->plt->sh_addr + rel->r_addend;
+	    /* fallthrough.  */
+
+	plt32pc32:
+	{
+            long long diff;
+            diff = (long long)val - addr;
+            if (diff < -2147483648LL || diff > 2147483647LL) {
+                tcc_error("internal error: relocation failed");
+            }
+            add32le(ptr, diff);
+        }
+            break;
+        case R_X86_64_GLOB_DAT:
+        case R_X86_64_JUMP_SLOT:
+            /* They don't need addend */
+            write64le(ptr, val - rel->r_addend);
+            break;
+        case R_X86_64_GOTPCREL:
+	case R_X86_64_GOTPCRELX:
+	case R_X86_64_REX_GOTPCRELX:
+            add32le(ptr, s1->got->sh_addr - addr +
+                         s1->sym_attrs[sym_index].got_offset - 4);
+            break;
+        case R_X86_64_GOTTPOFF:
+            add32le(ptr, val - s1->got->sh_addr);
+            break;
+        case R_X86_64_GOT32:
+            /* we load the got offset */
+            add32le(ptr, s1->sym_attrs[sym_index].got_offset);
+            break;
+    }
+}
-- 
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