[PATCH] D58693: [AArch64] [Windows] Fix llvm-readobj -unwind output with many epilogs.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added reviewers: ssijaric, rnk.
Herald added subscribers: kristina, rupprecht, kristof.beyls, javed.absar.
Herald added a project: LLVM.

The number of epilog scopes may not fit into a uint8_t.

Fixes https://bugs.llvm.org/show_bug.cgi?id=40855


Repository:
  rL LLVM

https://reviews.llvm.org/D58693

Files:
  include/llvm/Support/ARMWinEH.h
  test/tools/llvm-readobj/arm64-many-epilogs.s


Index: test/tools/llvm-readobj/arm64-many-epilogs.s
===================================================================
--- /dev/null
+++ test/tools/llvm-readobj/arm64-many-epilogs.s
@@ -0,0 +1,26 @@
+// REQUIRES: aarch64-registered-target
+// RUN: llvm-mc -filetype=obj -triple aarch64-windows %s -o - \
+// RUN:   | not llvm-readobj -unwind - | FileCheck %s
+
+// Older versions of LLVM had a bug where we would accidentally
+// truncate the number of epilogue scopes to a uint8_t; make
+// sure this doesn't happen.
+//
+// We expect the llvm-readobj invocation to fail because the
+// xdata section is truncated (to reduce the size of the testcase).
+
+// CHECK: EpilogueScopes: 256
+
+.section .pdata,"dr"
+        .long "?func@@YAHXZ"@IMGREL
+        .long "$unwind$func@@YAHXZ"@IMGREL
+
+        .text
+        .globl  "?func@@YAHXZ"
+        .p2align        3
+"?func@@YAHXZ":
+        ret
+
+.section        .xdata,"dr"
+"$unwind$func@@YAHXZ":
+.long 0x00000000, 0x02010100, 0x09000000, 0x0A000000
Index: include/llvm/Support/ARMWinEH.h
===================================================================
--- include/llvm/Support/ARMWinEH.h
+++ include/llvm/Support/ARMWinEH.h
@@ -382,7 +382,7 @@
     return ((Data[0] & 0x00400000) >> 22);
   }
 
-  uint8_t EpilogueCount() const {
+  uint16_t EpilogueCount() const {
     if (HeaderWords(*this) == 1) {
       if (isAArch64)
         return (Data[0] & 0x07C00000) >> 22;


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