[PATCH] D131393: [MC] [Win64EH] Fix the calculation of the end of epilogs

[Martin Storsjö via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG0c52ab39688e: [MC] [Win64EH] Fix the calculation of the end of epilogs (authored by mstorsjo).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D131393/new/

https://reviews.llvm.org/D131393

Files:
  llvm/lib/MC/MCWin64EH.cpp
  llvm/test/MC/AArch64/seh-multi-epilog.s


Index: llvm/test/MC/AArch64/seh-multi-epilog.s
===================================================================
--- /dev/null
+++ llvm/test/MC/AArch64/seh-multi-epilog.s
@@ -0,0 +1,62 @@
+// This test checks that we emit allow multiple consecutive epilogs without
+// triggering failed asserts.unwind info correctly for epilogs that:
+// RUN: llvm-mc -triple aarch64-pc-win32 -filetype=obj %s -o %t.o
+// RUN: llvm-readobj -u %t.o | FileCheck %s
+
+// CHECK-LABEL:UnwindInformation [
+// CHECK-NEXT:  RuntimeFunction {
+// CHECK-NEXT:    Function: multi_epilog (0x0)
+// CHECK-NEXT:    ExceptionRecord: .xdata (0x0)
+// CHECK-NEXT:    ExceptionData {
+// CHECK-NEXT:      FunctionLength: 20
+// CHECK-NEXT:      Version: 0
+// CHECK-NEXT:      ExceptionData: No
+// CHECK-NEXT:      EpiloguePacked: No
+// CHECK-NEXT:      EpilogueScopes: 2
+// CHECK-NEXT:      ByteCodeLength: 4
+// CHECK-NEXT:      Prologue [
+// CHECK-NEXT:        0x81                ; stp x29, x30, [sp, #-16]!
+// CHECK-NEXT:        0xe4                ; end
+// CHECK-NEXT:      ]
+// CHECK-NEXT:      EpilogueScopes [
+// CHECK-NEXT:        EpilogueScope {
+// CHECK-NEXT:          StartOffset: 2
+// CHECK-NEXT:          EpilogueStartIndex: 0
+// CHECK-NEXT:          Opcodes [
+// CHECK-NEXT:            0x81                ; ldp x29, x30, [sp], #16
+// CHECK-NEXT:            0xe4                ; end
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:        EpilogueScope {
+// CHECK-NEXT:          StartOffset: 3
+// CHECK-NEXT:          EpilogueStartIndex: 0
+// CHECK-NEXT:          Opcodes [
+// CHECK-NEXT:            0x81                ; ldp x29, x30, [sp], #16
+// CHECK-NEXT:            0xe4                ; end
+// CHECK-NEXT:          ]
+// CHECK-NEXT:        }
+// CHECK-NEXT:      ]
+// CHECK-NEXT:    }
+// CHECK-NEXT:  }
+// CHECK-NEXT:]
+
+	.text
+	.global	multi_epilog
+	.p2align	2
+	.seh_proc multi_epilog
+multi_epilog:
+	stp	x29, lr, [sp, #-16]!
+	.seh_save_fplr_x 16
+	.seh_endprologue
+        nop
+	.seh_startepilogue
+	ldp	x29, lr, [sp], #16
+	.seh_save_fplr_x 16
+	.seh_endepilogue
+	.seh_startepilogue
+	ldp	x29, lr, [sp], #16
+	.seh_save_fplr_x 16
+	.seh_endepilogue
+	ret
+	.seh_endfunclet
+	.seh_endproc
Index: llvm/lib/MC/MCWin64EH.cpp
===================================================================
--- llvm/lib/MC/MCWin64EH.cpp
+++ llvm/lib/MC/MCWin64EH.cpp
@@ -997,7 +997,9 @@
     int64_t Offset = GetAbsDifference(streamer, Start, info->Begin);
     assert((Epilogs.size() == 0 || Offset >= Epilogs.back().End) &&
            "Epilogs should be monotonically ordered");
-    Epilogs.push_back({Start, Offset, Offset + (int64_t)Instrs.size() * 4});
+    // Exclue the end opcode from Instrs.size() when calculating the end of the
+    // epilog.
+    Epilogs.push_back({Start, Offset, Offset + (int64_t)(Instrs.size() - 1) * 4});
   }
 
   unsigned E = 0;


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