Windows/x86: Add full exception interoperability.

Contributed by Peter Cawley.

2 files changed, 27 insertions, 3 deletions

diff --git a/src/host/buildvm.c b/src/host/buildvm.c
index 6d9e09e1..57b4dc97 100644
--- a/src/host/buildvm.c
+++ b/src/host/buildvm.c
@@ -110,7 +110,7 @@ static const char *sym_decorate(BuildCtx *ctx,
   if (p) {
 #if LJ_TARGET_X86ORX64
     if (!LJ_64 && (ctx->mode == BUILD_coffasm || ctx->mode == BUILD_peobj))
-      name[0] = '@';
+      name[0] = name[1] == 'R' ? '_' : '@';  /* Just for _RtlUnwind@16. */
     else
       *p = '\0';
 #elif LJ_TARGET_PPC && !LJ_TARGET_CONSOLE
diff --git a/src/host/buildvm_peobj.c b/src/host/buildvm_peobj.c
index e8c927d8..42f6ac84 100644
--- a/src/host/buildvm_peobj.c
+++ b/src/host/buildvm_peobj.c
@@ -109,6 +109,8 @@ enum {
 #if LJ_TARGET_X64
   PEOBJ_SECT_PDATA,
   PEOBJ_SECT_XDATA,
+#elif LJ_TARGET_X86
+  PEOBJ_SECT_SXDATA,
 #endif
   PEOBJ_SECT_RDATA_Z,
   PEOBJ_NSECTIONS
@@ -208,6 +210,13 @@ void emit_peobj(BuildCtx *ctx)
   sofs += (pesect[PEOBJ_SECT_XDATA].nreloc = 1) * PEOBJ_RELOC_SIZE;
   /* Flags: 40 = read, 30 = align4, 40 = initialized data. */
   pesect[PEOBJ_SECT_XDATA].flags = 0x40300040;
+#elif LJ_TARGET_X86
+  memcpy(pesect[PEOBJ_SECT_SXDATA].name, ".sxdata", sizeof(".sxdata")-1);
+  pesect[PEOBJ_SECT_SXDATA].ofs = sofs;
+  sofs += (pesect[PEOBJ_SECT_SXDATA].size = 4);
+  pesect[PEOBJ_SECT_SXDATA].relocofs = sofs;
+  /* Flags: 40 = read, 30 = align4, 02 = lnk_info, 40 = initialized data. */
+  pesect[PEOBJ_SECT_SXDATA].flags = 0x40300240;
 #endif
 
   memcpy(pesect[PEOBJ_SECT_RDATA_Z].name, ".rdata$Z", sizeof(".rdata$Z")-1);
@@ -232,7 +241,7 @@ void emit_peobj(BuildCtx *ctx)
   nrsym = ctx->nrelocsym;
   pehdr.nsyms = 1+PEOBJ_NSECTIONS*2 + 1+ctx->nsym + nrsym;
 #if LJ_TARGET_X64
-  pehdr.nsyms += 1;  /* Symbol for lj_err_unwind_win64. */
+  pehdr.nsyms += 1;  /* Symbol for lj_err_unwind_win. */
 #endif
 
   /* Write PE object header and all sections. */
@@ -312,6 +321,19 @@ void emit_peobj(BuildCtx *ctx)
     reloc.type = PEOBJ_RELOC_ADDR32NB;
     owrite(ctx, &reloc, PEOBJ_RELOC_SIZE);
   }
+#elif LJ_TARGET_X86
+  /* Write .sxdata section. */
+  for (i = 0; i < nrsym; i++) {
+    if (!strcmp(ctx->relocsym[i], "_lj_err_unwind_win")) {
+      uint32_t symidx = 1+2+i;
+      owrite(ctx, &symidx, 4);
+      break;
+    }
+  }
+  if (i == nrsym) {
+    fprintf(stderr, "Error: extern lj_err_unwind_win not used\n");
+    exit(1);
+  }
 #endif
 
   /* Write .rdata$Z section. */
@@ -333,8 +355,10 @@ void emit_peobj(BuildCtx *ctx)
 #if LJ_TARGET_X64
     emit_peobj_sym_sect(ctx, pesect, PEOBJ_SECT_PDATA);
     emit_peobj_sym_sect(ctx, pesect, PEOBJ_SECT_XDATA);
-    emit_peobj_sym(ctx, "lj_err_unwind_win64", 0,
+    emit_peobj_sym(ctx, "lj_err_unwind_win", 0,
                    PEOBJ_SECT_UNDEF, PEOBJ_TYPE_FUNC, PEOBJ_SCL_EXTERN);
+#elif LJ_TARGET_X86
+    emit_peobj_sym_sect(ctx, pesect, PEOBJ_SECT_SXDATA);
 #endif
 
     emit_peobj_sym(ctx, ctx->beginsym, 0,