[PATCH] D118490: [lld][ELF] add .note sections from linker scripts as SHT_NOTE

[Luca Boccassi via Phabricator via llvm-commits]

bluca updated this revision to Diff 404286.
bluca added a comment.

v2: removed SHF_ALLOC fixup, as it is fixed by https://reviews.llvm.org/D118530


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118490/new/

https://reviews.llvm.org/D118490

Files:
  lld/ELF/LinkerScript.cpp
  lld/test/ELF/linkerscript/note-section.test


Index: lld/test/ELF/linkerscript/note-section.test
===================================================================
--- /dev/null
+++ lld/test/ELF/linkerscript/note-section.test
@@ -0,0 +1,37 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux /dev/null -o %t.o
+# RUN: ld.lld -o %t --build-id --script %s %t.o -shared
+# RUN: llvm-readobj -S --symbols %t | FileCheck %s
+
+SECTIONS
+{
+    .note.package : ALIGN(4) {
+        BYTE(0x04) BYTE(0x00) BYTE(0x00) BYTE(0x00) /* Length of Owner including NUL */
+        BYTE(0x0e) BYTE(0x00) BYTE(0x00) BYTE(0x00) /* Length of Value including NUL */
+        BYTE(0xaa) BYTE(0xaa) BYTE(0xaa) BYTE(0xaa) /* Note ID */
+        BYTE(0x4f) BYTE(0x4f) BYTE(0x4f) BYTE(0x00) /* Owner: 'FFF\x00' */
+        BYTE(0x7b) BYTE(0x22) BYTE(0x66) BYTE(0x6f) /* Value: '{"foo":"bar"}\x00\x00\x00' */
+        BYTE(0x6f) BYTE(0x22) BYTE(0x3a) BYTE(0x22)
+        BYTE(0x62) BYTE(0x61) BYTE(0x72) BYTE(0x22)
+        BYTE(0x7d) BYTE(0x00) BYTE(0x00) BYTE(0x00)
+    }
+}
+INSERT AFTER .note.gnu.build-id;
+
+# Make sure the section has type SHT_NOTE and it's marked as
+# allocatable
+# CHECK:       Section {
+# CHECK:         Index:
+# CHECK:         Name: .note.package
+# CHECK-NEXT:    Type: SHT_NOTE
+# CHECK-NEXT:    Flags [
+# CHECK-NEXT:      SHF_ALLOC
+# CHECK-NEXT:    ]
+# CHECK-NEXT:    Address:
+# CHECK-NEXT:    Offset:
+# CHECK-NEXT:    Size:
+# CHECK-NEXT:    Link:
+# CHECK-NEXT:    Info:
+# CHECK-NEXT:    AddressAlignment: 4
+# CHECK-NEXT:    EntrySize:
+# CHECK-NEXT:  }
Index: lld/ELF/LinkerScript.cpp
===================================================================
--- lld/ELF/LinkerScript.cpp
+++ lld/ELF/LinkerScript.cpp
@@ -141,7 +141,17 @@
     // There was a forward reference.
     sec = secRef;
   } else {
-    sec = make<OutputSection>(name, SHT_PROGBITS, 0);
+    uint32_t type = SHT_PROGBITS;
+    uint64_t flags = 0;
+
+    // For compatibility with ld.bfd, mark sections starting with .note as
+    // SHT_NOTE and make them allocatable.
+    if (name.startswith_insensitive(".note.")) {
+      type = SHT_NOTE;
+      flags = SHF_ALLOC;
+    }
+
+    sec = make<OutputSection>(name, type, flags);
     if (!secRef)
       secRef = sec;
   }
@@ -151,8 +161,19 @@
 
 OutputSection *LinkerScript::getOrCreateOutputSection(StringRef name) {
   OutputSection *&cmdRef = nameToOutputSection[CachedHashStringRef(name)];
-  if (!cmdRef)
-    cmdRef = make<OutputSection>(name, SHT_PROGBITS, 0);
+  if (!cmdRef) {
+    uint32_t type = SHT_PROGBITS;
+    uint64_t flags = 0;
+
+    // For compatibility with ld.bfd, mark sections starting with .note as
+    // SHT_NOTE and make them allocatable.
+    if (name.startswith_insensitive(".note.")) {
+      type = SHT_NOTE;
+      flags = SHF_ALLOC;
+    }
+
+    cmdRef = make<OutputSection>(name, type, flags);
+  }
   return cmdRef;
 }
 


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