[llvm] [Sframe] Support cfi_escape directives compatibly with gnu-gas (PR #161927)

[via llvm-commits]

================
@@ -265,8 +413,9 @@ class SFrameEmitterImpl {
       FRE = FDE.SaveState.pop_back_val();
       return true;
     case MCCFIInstruction::OpEscape:
-      // TODO: Implement. Will use FDE.
-      return true;
+      // This is a string of bytes that contains an aribtrary dwarf-expression
+      // that may or may not affect uwnind info.
+      return isCFIEscapeSafe(FDE, FRE, CFI);
     default:
       // Instructions that don't affect the CFA, RA, and SP can be safely
----------------
weiguozhi wrote:

CFA, RA and FP

https://github.com/llvm/llvm-project/pull/161927