[PATCH] D93954: ELF: Teach the linker about the 'B' augmentation string character.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc created this revision.
pcc added reviewers: MaskRay, psmith.
Herald added subscribers: arichardson, emaste.
Herald added a reviewer: espindola.
pcc requested review of this revision.
Herald added a project: LLVM.

This character indicates that when return pointer authentication is
being used, the function signs the return address using the B key.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93954

Files:
  lld/ELF/EhFrame.cpp
  lld/test/ELF/cfi-b-key-frame.s


Index: lld/test/ELF/cfi-b-key-frame.s
===================================================================
--- /dev/null
+++ lld/test/ELF/cfi-b-key-frame.s
@@ -0,0 +1,9 @@
+// REQUIRES: aarch64
+// RUN: llvm-mc -filetype=obj -triple aarch64-arm-none-eabi %s -o %t.o
+// RUN: ld.lld %t.o -o %t --icf=all --eh-frame-hdr
+
+.globl _start
+_start:
+.cfi_startproc
+.cfi_b_key_frame
+.cfi_endproc
Index: lld/ELF/EhFrame.cpp
===================================================================
--- lld/ELF/EhFrame.cpp
+++ lld/ELF/EhFrame.cpp
@@ -194,7 +194,7 @@
       readByte();
     else if (c == 'P')
       skipAugP();
-    else if (c != 'S')
+    else if (c != 'B' && c != 'S')
       failOn(aug.data(), "unknown .eh_frame augmentation string: " + aug);
   }
   return DW_EH_PE_absptr;
@@ -211,7 +211,7 @@
       skipAugP();
     else if (c == 'R')
       readByte();
-    else if (c != 'S')
+    else if (c != 'B' && c != 'S')
       failOn(aug.data(), "unknown .eh_frame augmentation string: " + aug);
   }
   return false;


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