[PATCH] x86: Use DW_EH_PE_indirect|DW_EH_PE_pcrel encodings for -fno-pic code

[Fangrui Song via Gcc-patches]

Follow aarch64 and riscv ports by using (global ? DW_EH_PE_indirect : 0)
| DW_EH_PE_pcrel for -fno-pic code.  This avoids a canonical PLT entry
for a personality reference in .eh_frame and a copy relocation for a
typeinfo reference in .gcc_except_table, when the definition is in
libstdc++.so.6.

gcc/

    PR target/108622
    * config/i386/i386.cc (asm_preferred_eh_data_format): Always use the
    PIC encoding. Use DW_EH_PE_indirect if global.
---
 gcc/config/i386/i386.cc | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 3cacf738c4a..b572dd46a62 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -22851,22 +22851,13 @@ ix86_stack_protect_fail (void)
 int
 asm_preferred_eh_data_format (int code, int global)
 {
-  /* PE-COFF is effectively always -fPIC because of the .reloc section.  */
-  if (flag_pic || TARGET_PECOFF || !ix86_direct_extern_access)
-    {
-      int type = DW_EH_PE_sdata8;
-      if (ptr_mode == SImode
-         || ix86_cmodel == CM_SMALL_PIC
-         || (ix86_cmodel == CM_MEDIUM_PIC && (global || code)))
-       type = DW_EH_PE_sdata4;
-      return (global ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | type;
-    }
-
-  if (ix86_cmodel == CM_SMALL
-      || (ix86_cmodel == CM_MEDIUM && code))
-    return DW_EH_PE_udata4;
-
-  return DW_EH_PE_absptr;
+  int type = DW_EH_PE_sdata8;
+  if (ptr_mode == SImode || ix86_cmodel == CM_SMALL ||
+      ix86_cmodel == CM_SMALL_PIC ||
+      (ix86_cmodel == CM_MEDIUM && code) ||
+      (ix86_cmodel == CM_MEDIUM_PIC && (global || code)))
+    type = DW_EH_PE_sdata4;
+  return (global ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | type;
 }
 
 /* Implement targetm.vectorize.builtin_vectorization_cost.  */
-- 
2.39.1.456.gfc5497dd1b-goog