[PATCH] D70962: [LLD][ELF][AArch64] .note.gnu.property sections should have alignment 8

[Peter Smith via Phabricator via llvm-commits]

peter.smith updated this revision to Diff 231898.
peter.smith added a comment.

Updated to add context.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D70962/new/

https://reviews.llvm.org/D70962

Files:
  lld/ELF/SyntheticSections.cpp
  lld/test/ELF/aarch64-gnu-property-align.s
  lld/test/ELF/aarch64-pt-gnu-property.s


Index: lld/test/ELF/aarch64-pt-gnu-property.s
===================================================================
--- lld/test/ELF/aarch64-pt-gnu-property.s
+++ lld/test/ELF/aarch64-pt-gnu-property.s
@@ -16,7 +16,7 @@
 # CHECK-NEXT:     Size: 32
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
-# CHECK-NEXT:     AddressAlignment: 4
+# CHECK-NEXT:     AddressAlignment: 8
 
 # CHECK:          Type: PT_GNU_PROPERTY (0x6474E553)
 # CHECK-NEXT:     Offset: 0x190
@@ -27,7 +27,7 @@
 # CHECK-NEXT:     Flags [ (0x4)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:     ]
-# CHECK-NEXT:     Alignment: 4
+# CHECK-NEXT:     Alignment: 8
 
 .section ".note.gnu.property", "a"
 .long 4
Index: lld/test/ELF/aarch64-gnu-property-align.s
===================================================================
--- /dev/null
+++ lld/test/ELF/aarch64-gnu-property-align.s
@@ -0,0 +1,42 @@
+# REQUIRES: aarch64
+# RUN: llvm-mc -filetype=obj -triple=aarch64-linux-gnu %s -o %t.o
+# RUN: ld.lld %t.o -o %t
+# RUN: llvm-readobj --sections -n %t | FileCheck %s
+
+## Check that .note.gnu.property has alignment 8 and is readable by llvm-readobj
+
+# CHECK:     Name: .note.gnu.property
+# CHECK-NEXT:     Type: SHT_NOTE (0x7)
+# CHECK-NEXT:     Flags [ (0x2)
+# CHECK-NEXT:       SHF_ALLOC (0x2)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Address: 0x200190
+# CHECK-NEXT:     Offset: 0x190
+# CHECK-NEXT:     Size: 32
+# CHECK-NEXT:     Link: 0
+# CHECK-NEXT:     Info: 0
+# CHECK-NEXT:     AddressAlignment: 8
+
+# CHECK:     Note {
+# CHECK-NEXT:       Owner: GNU
+# CHECK-NEXT:       Data size: 0x10
+# CHECK-NEXT:       Type: NT_GNU_PROPERTY_TYPE_0 (property note)
+# CHECK-NEXT:       Property [
+# CHECK-NEXT:         aarch64 feature: BTI, PAC
+
+
+.section ".note.gnu.property", "a"
+.balign 8
+.long 4
+.long 0x10
+.long 0x5
+.asciz "GNU"
+.long 0xc0000000 // GNU_PROPERTY_AARCH64_FEATURE_1_AND
+.long 4
+.long 3          // GNU_PROPERTY_AARCH64_FEATURE_1_BTI and PAC
+.long 0
+
+ .text
+ .globl _start
+ .type _start, %function
+_start: ret
Index: lld/ELF/SyntheticSections.cpp
===================================================================
--- lld/ELF/SyntheticSections.cpp
+++ lld/ELF/SyntheticSections.cpp
@@ -298,8 +298,8 @@
 // sets is empty, or some input files didn't have .note.gnu.property sections),
 // we don't create this section.
 GnuPropertySection::GnuPropertySection()
-    : SyntheticSection(llvm::ELF::SHF_ALLOC, llvm::ELF::SHT_NOTE, 4,
-                       ".note.gnu.property") {}
+    : SyntheticSection(llvm::ELF::SHF_ALLOC, llvm::ELF::SHT_NOTE,
+                       config->is64 ? 8 : 4, ".note.gnu.property") {}
 
 void GnuPropertySection::writeTo(uint8_t *buf) {
   uint32_t featureAndType = config->emachine == EM_AARCH64


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