DWARF

pablogsal · pablogsal · commit 0d9cdd151527 · 2025-07-10T11:23:51.000+01:00
diff --git a/Python/asm_trampoline.S b/Python/asm_trampoline.S
@@ -12,9 +12,10 @@ _Py_trampoline_func_start:
 #if defined(__CET__) && (__CET__ & 1)
     endbr64
 #endif
-    sub    $8, %rsp
-    call    *%rcx
-    add    $8, %rsp
+    push   %rbp
+    mov    %rsp, %rbp
+    call   *%rcx
+    pop    %rbp
     ret
 #endif // __x86_64__
 #if defined(__aarch64__) && defined(__AARCH64EL__) && !defined(__ILP32__)
diff --git a/Python/perf_jit_trampoline.c b/Python/perf_jit_trampoline.c
@@ -401,10 +401,12 @@ enum {
     DWRF_CFA_nop = 0x0,                    // No operation
     DWRF_CFA_offset_extended = 0x5,        // Extended offset instruction
     DWRF_CFA_def_cfa = 0xc,               // Define CFA rule
+    DWRF_CFA_def_cfa_register = 0xd,      // Define CFA register
     DWRF_CFA_def_cfa_offset = 0xe,        // Define CFA offset
     DWRF_CFA_offset_extended_sf = 0x11,   // Extended signed offset
     DWRF_CFA_advance_loc = 0x40,          // Advance location counter
-    DWRF_CFA_offset = 0x80                // Simple offset instruction
+    DWRF_CFA_offset = 0x80,               // Simple offset instruction
+    DWRF_CFA_restore = 0xc0               // Restore register
 };
 
 /* DWARF Exception Handling pointer encodings */
@@ -868,17 +870,22 @@ static void elf_init_ehframe(ELFObjectContext* ctx) {
          * conventions and register usage patterns.
          */
 #ifdef __x86_64__
-        /* x86_64 calling convention unwinding rules */
+        /* x86_64 calling convention unwinding rules with frame pointer */
 #  if defined(__CET__) && (__CET__ & 1)
-        DWRF_U8(DWRF_CFA_advance_loc | 8);    // Advance location by 8 bytes when CET protection is enabled
-#  else
-        DWRF_U8(DWRF_CFA_advance_loc | 4);    // Advance location by 4 bytes
+        DWRF_U8(DWRF_CFA_advance_loc | 4);    // Advance past endbr64 (4 bytes)
 #  endif
-        DWRF_U8(DWRF_CFA_def_cfa_offset);     // Redefine CFA offset
-        DWRF_UV(16);                          // New offset: SP + 16
-        DWRF_U8(DWRF_CFA_advance_loc | 6);    // Advance location by 6 bytes
-        DWRF_U8(DWRF_CFA_def_cfa_offset);     // Redefine CFA offset
-        DWRF_UV(8);                           // New offset: SP + 8
+        DWRF_U8(DWRF_CFA_advance_loc | 1);    // Advance past push %rbp (1 byte)
+        DWRF_U8(DWRF_CFA_def_cfa_offset);     // def_cfa_offset 16
+        DWRF_UV(16);
+        DWRF_U8(DWRF_CFA_offset | DWRF_REG_BP); // offset r6 at cfa-16
+        DWRF_UV(2);
+        DWRF_U8(DWRF_CFA_advance_loc | 3);    // Advance past mov %rsp,%rbp (3 bytes)
+        DWRF_U8(DWRF_CFA_def_cfa_register);   // def_cfa_register r6
+        DWRF_UV(DWRF_REG_BP);
+        DWRF_U8(DWRF_CFA_advance_loc | 3);    // Advance past call *%rcx (2 bytes) + pop %rbp (1 byte) = 3
+        DWRF_U8(DWRF_CFA_def_cfa);            // def_cfa r7 ofs 8
+        DWRF_UV(DWRF_REG_SP);
+        DWRF_UV(8);
 #elif defined(__aarch64__) && defined(__AARCH64EL__) && !defined(__ILP32__)
         /* AArch64 calling convention unwinding rules */
         DWRF_U8(DWRF_CFA_advance_loc | 1);        // Advance location by 1 instruction (stp x29, x30)
