Win64: IMAGEREL references (SEH support for Win64)

Guess what, SEH again, but in Win64 context, which is completely
different matter from Win32. At lowest level this one boils down to
putting so called imagerel references, or in practical terms
relocations of type ADDR32NB, 0x0003, into .pdata and .xdata
segments. Two possibilities. 1. implement say 'wrt ..imagerel' or 'wrt
..imagebase'. 2. silently enforce ADDR32NB relocations in .pdata and
.xdata segments.

1 files changed, 39 insertions, 22 deletions

diff --git a/output/outcoff.c b/output/outcoff.c
index 259c766..ae880cb 100644
--- a/output/outcoff.c
+++ b/output/outcoff.c
@@ -68,6 +68,9 @@
 /* Flag which version of COFF we are currently outputting. */
 static bool win32, win64;
 
+static int32_t imagebase_sect;
+#define WRT_IMAGEBASE "..imagebase"
+
 struct Reloc {
     struct Reloc *next;
     int32_t address;		/* relative to _start_ of section */
@@ -77,10 +80,18 @@ struct Reloc {
         ABS_SYMBOL,
         REAL_SYMBOLS
     } symbase;                  /* relocation for symbol number :) */
-    bool relative;
-    bool size64;
+    int16_t type;
 };
 
+/* possible values for Reloc->type */
+#define IMAGE_REL_AMD64_ADDR64		0x0001
+#define IMAGE_REL_AMD64_ADDR32		0x0002
+#define IMAGE_REL_AMD64_ADDR32NB	0x0003
+#define IMAGE_REL_AMD64_REL32		0x0004
+#define IMAGE_REL_I386_DIR32		0x0006
+#define IMAGE_REL_I386_DIR32NB		0x0007
+#define IMAGE_REL_I386_REL32		0x0014
+
 struct Symbol {
     char name[9];
     int32_t strpos;		/* string table position of name */
@@ -149,11 +160,15 @@ static void coff_win32_init(FILE * fp, efunc errfunc,
 static void coff_win64_init(FILE * fp, efunc errfunc,
                             ldfunc ldef, evalfunc eval)
 {
+    extern struct ofmt of_win64;
+
     maxbits = 64;
     win32 = false; win64 = true;
     (void)ldef;                 /* placate optimizers */
     (void)eval;
     coff_gen_init(fp, errfunc);
+    imagebase_sect = seg_alloc()+1;
+    ldef(WRT_IMAGEBASE,imagebase_sect,0,NULL,false,false,&of_win64,errfunc);
 }
 
 static void coff_std_init(FILE * fp, efunc errfunc, ldfunc ldef,
@@ -343,6 +358,10 @@ static int32_t coff_section_names(char *name, int pass, int *bits)
                 flags = RDATA_FLAGS;
             else if (!strcmp(name, ".bss"))
                 flags = BSS_FLAGS;
+	    else if (win64 && !strcmp(name, ".pdata"))
+		flags = 0x40300040; /* rdata align=4 */
+	    else if (win64 && !strcmp(name, ".xdata"))
+		flags = 0x40400040; /* rdate align=8 */
             else
                 flags = TEXT_FLAGS;
         }
@@ -371,7 +390,8 @@ static void coff_deflabel(char *name, int32_t segment, int64_t offset,
               " special symbol types");
 
     if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
-        error(ERR_NONFATAL, "unrecognized special symbol `%s'", name);
+	if (strcmp(name,WRT_IMAGEBASE))
+            error(ERR_NONFATAL, "unrecognized special symbol `%s'", name);
         return;
     }
 
@@ -421,12 +441,10 @@ static void coff_deflabel(char *name, int32_t segment, int64_t offset,
 }
 
 static int32_t coff_add_reloc(struct Section *sect, int32_t segment,
-                           int relative, int size64)
+				int16_t type)
 {
     struct Reloc *r;
 
-    (void)size64;
-
     r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
     sect->tail = &r->next;
     r->next = NULL;
@@ -446,7 +464,7 @@ static int32_t coff_add_reloc(struct Section *sect, int32_t segment,
         if (r->symbase == REAL_SYMBOLS)
             r->symbol = raa_read(bsym, segment);
     }
-    r->relative = relative;
+    r->type = type;
 
     sect->nrelocs++;
 
@@ -467,7 +485,7 @@ static void coff_out(int32_t segto, const void *data,
     uint8_t mydata[8], *p;
     int i;
 
-    if (wrt != NO_SEG) {
+    if (wrt != NO_SEG && !win64) {
         wrt = NO_SEG;           /* continue to do _something_ */
         error(ERR_NONFATAL, "WRT not supported by COFF output formats");
     }
@@ -496,6 +514,11 @@ static void coff_out(int32_t segto, const void *data,
             s = sects[nsects - 1];
     }
 
+    /* magically default to 'wrt ..imagebase' in .pdata and .xdata */
+    if (win64 && wrt == NO_SEG &&
+	(!strcmp(s->name,".pdata") || !strcmp(s->name,".xdata")))
+	wrt = imagebase_sect;
+
     if (!s->data && type != OUT_RESERVE) {
         error(ERR_WARNING, "attempt to initialize memory in"
               " BSS section `%s': ignored", s->name);
@@ -533,7 +556,7 @@ static void coff_out(int32_t segto, const void *data,
                         error(ERR_NONFATAL, "COFF format does not support"
                               " segment base references");
                     } else
-                        fix = coff_add_reloc(s, segment, false, false);
+                        fix = coff_add_reloc(s, segment, IMAGE_REL_I386_DIR32);
                 }
                 p = mydata;
                 WRITELONG(p, *(int64_t *)data + fix);
@@ -553,11 +576,13 @@ static void coff_out(int32_t segto, const void *data,
                 } else
                     fix = coff_add_reloc(s, segment, false);
             } */
-                fix = coff_add_reloc(s, segment, false, true);
+                fix = coff_add_reloc(s, segment, IMAGE_REL_AMD64_ADDR64);
                 WRITEDLONG(p, *(int64_t *)data + fix);
                 coff_sect_write(s, mydata, size);
             } else {
-                fix = coff_add_reloc(s, segment, false, false);
+                fix = coff_add_reloc(s, segment,
+			wrt == imagebase_sect ?	IMAGE_REL_AMD64_ADDR32NB:
+						IMAGE_REL_AMD64_ADDR32);
                 WRITELONG(p, *(int64_t *)data + fix);
                 coff_sect_write(s, mydata, size);
             }
@@ -577,7 +602,8 @@ static void coff_out(int32_t segto, const void *data,
                 error(ERR_NONFATAL, "COFF format does not support"
                       " segment base references");
             } else
-                fix = coff_add_reloc(s, segment, true, false);
+                fix = coff_add_reloc(s, segment,
+			win64 ? IMAGE_REL_AMD64_REL32 : IMAGE_REL_I386_REL32);
             p = mydata;
             if (win32 | win64) {
                 WRITELONG(p, *(int64_t *)data + 4 - size + fix);
@@ -858,16 +884,7 @@ static void coff_write_relocs(struct Section *s)
                                 r->symbase == ABS_SYMBOL ? initsym - 1 :
                                 r->symbase == SECT_SYMBOLS ? 2 : 0),
                    coffp);
-        /*
-         * Strange: Microsoft's COFF documentation says 0x03 for an
-         * absolute relocation, but both Visual C++ and DJGPP agree
-         * that in fact it's 0x06. I'll use 0x06 until someone
-         * argues. ***** UPDATE: PE/COFF Ver.8 docs confirm this -kkanios *****
-         */
-        if (win64)
-            fwriteint16_t(r->relative ? 0x04 : r->size64 ? 0x01 : 0x02, coffp);
-        else
-            fwriteint16_t(r->relative ? 0x14 : 0x06, coffp);
+	fwriteint16_t(r->type, coffp);
     }
 }