Re: [Tinycc-devel] Win64 PE JIT codegen: Bad unwind info / runtime function tables

[grischka]

Janus Lynggaard Thorborg wrote:
> Okay, so I thought everything was good, but it turns out one of the real
> issues was adding mixing object files and compilations into one tcc state,
> something my unit tests didn't cover. So here's a dump of the
> RUNTIME_FUNCTION array passed to RtlAddFunctionTable, where I compiled some
> stuff using *tcc_compile_string* and *tcc_add_file("someobject.o")*:
> [...]
> As can be seen, from runtime function 14, the function entries start to
> overlap again. Probably, there's a missing segment/section offset somewhere
> when TCC adds runtime functions from different contexts/sections/object
> files?

Yes, I already wondered how it can work if for file output (exe/dll)
we handle R_XXX_RELATIVE in pe_relocate_rva() but don't do anything
like that for -run.  Not surprisingly it doesn't work.

Attached is a patch to correct this.  It removes pe_relocate_rva()
altogether and instead handles R_XXX_RELATIVE in the relocate backends
(as it should be).

It also sets the uw_pdata section in case it was not set by any
compilation, that is if you wanted to run just already compiled
object files.

If it works I'll push that later.

--- grischka

commit 7354711b9b6ba022f3b5f4959e057859b877e9cb
Author: grischka <grischka>
Date:   Mon Nov 6 10:45:43 2017 +0100

    win32/64: integrate pe_relocate_rva
    
    This fixes relocation of the unwind data on win64

diff --git a/arm-link.c b/arm-link.c
index aee35af..92a24eb 100644
--- a/arm-link.c
+++ b/arm-link.c
@@ -382,6 +382,12 @@ void relocate(TCCState *s1, ElfW_Rel *rel, int type, 
unsigned char *ptr, addr_t
             /* Nothing to do.  Normally used to indicate a dependency
                on a certain symbol (like for exception handling under EABI).  
*/
             return;
+        case R_ARM_RELATIVE:
+#ifdef TCC_TARGET_PE
+            add32le(ptr, val - s1->pe_imagebase);
+#endif
+            /* do nothing */
+            return;
         default:
             fprintf(stderr,"FIXME: handle reloc type %x at %x [%p] to %x\n",
                 type, (unsigned)addr, ptr, (unsigned)val);
diff --git a/arm64-link.c b/arm64-link.c
index 73e503e..59322c5 100644
--- a/arm64-link.c
+++ b/arm64-link.c
@@ -240,6 +240,12 @@ void relocate(TCCState *s1, ElfW_Rel *rel, int type, 
unsigned char *ptr, addr_t
 #endif
             write64le(ptr, val - rel->r_addend);
             return;
+        case R_AARCH64_RELATIVE:
+#ifdef TCC_TARGET_PE
+            add32le(ptr, val - s1->pe_imagebase);
+#endif
+            /* do nothing */
+            return;
         default:
             fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
                     type, (unsigned)addr, ptr, (unsigned)val);
diff --git a/i386-link.c b/i386-link.c
index b446644..aea3c21 100644
--- a/i386-link.c
+++ b/i386-link.c
@@ -226,6 +226,9 @@ void relocate(TCCState *s1, ElfW_Rel *rel, int type, 
unsigned char *ptr, addr_t
             write16le(ptr, read16le(ptr) + val - addr);
             return;
         case R_386_RELATIVE:
+#ifdef TCC_TARGET_PE
+            add32le(ptr, val - s1->pe_imagebase);
+#endif
             /* do nothing */
             return;
         case R_386_COPY:
diff --git a/tcc.h b/tcc.h
index da26298..02f4196 100644
--- a/tcc.h
+++ b/tcc.h
@@ -803,6 +803,7 @@ struct TCCState {
     unsigned pe_characteristics;
     unsigned pe_file_align;
     unsigned pe_stack_size;
+    addr_t pe_imagebase;
 # ifdef TCC_TARGET_X86_64
     Section *uw_pdata;
     int uw_sym;
diff --git a/tccpe.c b/tccpe.c
index a67023d..094e2f3 100644
--- a/tccpe.c
+++ b/tccpe.c
@@ -967,7 +967,7 @@ static void pe_build_exports(struct pe_info *pe)
     for (ord = 0; ord < sym_count; ++ord)
     {
         p = sorted[ord], sym_index = p->index, name = p->name;
-        /* insert actual address later in pe_relocate_rva */
+        /* insert actual address later in relocate_section() */
         put_elf_reloc(symtab_section, pe->thunk,
             func_o, R_XXX_RELATIVE, sym_index);
         *(DWORD*)(pe->thunk->data + name_o)
@@ -1181,26 +1181,6 @@ static int pe_assign_addresses (struct pe_info *pe)
     return 0;
 }
 
-/* ------------------------------------------------------------- */
-static void pe_relocate_rva (struct pe_info *pe, Section *s)
-{
-    Section *sr = s->reloc;
-    ElfW_Rel *rel, *rel_end;
-    rel_end = (ElfW_Rel *)(sr->data + sr->data_offset);
-    for(rel = (ElfW_Rel *)sr->data; rel < rel_end; rel++) {
-        if (ELFW(R_TYPE)(rel->r_info) == R_XXX_RELATIVE) {
-            int sym_index = ELFW(R_SYM)(rel->r_info);
-            DWORD addr = s->sh_addr;
-            if (sym_index) {
-                ElfW(Sym) *sym = (ElfW(Sym) *)symtab_section->data + sym_index;
-                addr = sym->st_value;
-            }
-            // printf("reloc rva %08x %08x %s\n", (DWORD)rel->r_offset, addr, 
s->name);
-            *(DWORD*)(s->data + rel->r_offset) += addr - pe->imagebase;
-        }
-    }
-}
-
 
/*----------------------------------------------------------------------------*/
 
 static int pe_isafunc(int sym_index)
@@ -1633,7 +1613,7 @@ static int pe_load_res(TCCState *s1, int fd)
 {
     struct pe_rsrc_header hdr;
     Section *rsrc_section;
-    int i, ret = -1;
+    int i, ret = -1, sym_index = 0;
     BYTE *ptr;
     unsigned offs;
 
@@ -1651,6 +1631,7 @@ static int pe_load_res(TCCState *s1, int fd)
     if (!read_mem(fd, offs, ptr, hdr.sectionhdr.SizeOfRawData))
         goto quit;
     offs = hdr.sectionhdr.PointerToRelocations;
+    sym_index = put_elf_sym(symtab_section, 0, 0, 0, 0, rsrc_section->sh_num, 
NULL);
     for (i = 0; i < hdr.sectionhdr.NumberOfRelocations; ++i)
     {
         struct pe_rsrc_reloc rel;
@@ -1660,7 +1641,7 @@ static int pe_load_res(TCCState *s1, int fd)
         if (rel.type != RSRC_RELTYPE)
             goto quit;
         put_elf_reloc(symtab_section, rsrc_section,
-            rel.offset, R_XXX_RELATIVE, 0);
+            rel.offset, R_XXX_RELATIVE, sym_index);
         offs += sizeof rel;
     }
     ret = 0;
@@ -1830,7 +1811,7 @@ ST_FUNC void pe_add_unwind_data(unsigned start, unsigned 
end, unsigned stack)
 
     /* put relocations on it */
     for (n = o + sizeof *p; o < n; o += sizeof p->BeginAddress)
-        put_elf_reloc(symtab_section, pd, o,  R_X86_64_RELATIVE, s1->uw_sym);
+        put_elf_reloc(symtab_section, pd, o, R_XXX_RELATIVE, s1->uw_sym);
 }
 #endif
 /* ------------------------------------------------------------- */
@@ -1980,11 +1961,11 @@ ST_FUNC int pe_output_file(TCCState *s1, const char 
*filename)
     else if (filename) {
         pe_assign_addresses(&pe);
         relocate_syms(s1, s1->symtab, 0);
+        s1->pe_imagebase = pe.imagebase;
         for (i = 1; i < s1->nb_sections; ++i) {
             Section *s = s1->sections[i];
             if (s->reloc) {
                 relocate_section(s1, s);
-                pe_relocate_rva(&pe, s);
             }
         }
         pe.start_addr = (DWORD)
@@ -2000,6 +1981,9 @@ ST_FUNC int pe_output_file(TCCState *s1, const char 
*filename)
         pe.thunk = data_section;
         pe_build_imports(&pe);
         s1->runtime_main = pe.start_symbol;
+#ifdef TCC_TARGET_X86_64
+        s1->uw_pdata = find_section(s1, ".pdata");
+#endif
 #endif
     }
 
diff --git a/tccrun.c b/tccrun.c
index d0501a0..bea67eb 100644
--- a/tccrun.c
+++ b/tccrun.c
@@ -239,6 +239,10 @@ static int tcc_relocate_ex(TCCState *s1, void *ptr, addr_t 
ptr_diff)
     if (0 == mem)
         return offset + RUN_SECTION_ALIGNMENT;
 
+#ifdef TCC_TARGET_PE
+    s1->pe_imagebase = mem;
+#endif
+
     /* relocate each section */
     for(i = 1; i < s1->nb_sections; i++) {
         s = s1->sections[i];
@@ -307,11 +311,11 @@ static void *win64_add_function_table(TCCState *s1)
         RtlAddFunctionTable(
             (RUNTIME_FUNCTION*)p,
             s1->uw_pdata->data_offset / sizeof (RUNTIME_FUNCTION),
-            text_section->sh_addr
+            s1->pe_imagebase
             );
         s1->uw_pdata = NULL;
     }
-    return p;;
+    return p;
 }
 
 static void win64_del_function_table(void *p)
diff --git a/x86_64-link.c b/x86_64-link.c
index c0c5e13..a96144c 100644
--- a/x86_64-link.c
+++ b/x86_64-link.c
@@ -287,6 +287,9 @@ void relocate(TCCState *s1, ElfW_Rel *rel, int type, 
unsigned char *ptr, addr_t
             add64le(ptr, val - s1->got->sh_addr);
             break;
         case R_X86_64_RELATIVE:
+#ifdef TCC_TARGET_PE
+            add32le(ptr, val - s1->pe_imagebase);
+#endif
             /* do nothing */
             break;
     }