[ELF] Respect NonAlloc when copying flags from the previous sections

Summary:
If the output section contains only symbol assignments, we copy flags
from the previous sections. Don't set SHF_ALLOC if NonAlloc is true.

We also have to change the type from SHT_NOBITS to SHT_PROGBITS.
In ld.bfd, bfd_elf_get_default_section_type maps non-alloctable sections to SHT_PROGBITS.
Non-alloctable SHT_NOBITS sections do not make sense.

Fixes PR38626

Differential Revision: https://reviews.llvm.org/D59986

llvm-svn: 358650

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index c4a63f5..c06c3bd 100644 (file)
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -887,7 +887,8 @@ void LinkerScript::adjustSectionsBeforeSorting() {
     // in case it is empty.
     bool IsEmpty = getInputSections(Sec).empty();
     if (IsEmpty)
-      Sec->Flags = Flags & (SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR);
+      Sec->Flags =
+          Flags & ((Sec->NonAlloc ? 0 : SHF_ALLOC) | SHF_WRITE | SHF_EXECINSTR);
 
     if (IsEmpty && isDiscardable(*Sec)) {
       Sec->Live = false;

diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index 96ab5cc..d757cd2 100644 (file)
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -752,6 +752,7 @@ bool ScriptParser::readSectionDirective(OutputSection *Cmd, StringRef Tok1, Stri
   } else {
     skip(); // This is "COPY", "INFO" or "OVERLAY".
     Cmd->NonAlloc = true;
+    Cmd->Type = SHT_PROGBITS;
   }
   expect(")");
   return true;

diff --git a/lld/test/ELF/linkerscript/info-section-type.s b/lld/test/ELF/linkerscript/info-section-type.s
index 16e663f..d54352d 100644 (file)
--- a/lld/test/ELF/linkerscript/info-section-type.s
+++ b/lld/test/ELF/linkerscript/info-section-type.s
@@ -29,6 +29,10 @@
 # RUN: ld.lld -o %t --script %t.script %t.o
 # RUN: llvm-readobj -sections %t | FileCheck %s --check-prefix=NONALLOC
 
+# RUN: echo "SECTIONS { .bar (INFO) : { . += 1; } };" > %t.script
+# RUN: ld.lld -o %t --script %t.script %t.o
+# RUN: llvm-readobj -sections %t | FileCheck %s --check-prefix=NONALLOC
+
 # RUN: echo "SECTIONS { .bar 0x20000 (INFO) : { *(.foo) } };" > %t.script
 # RUN: ld.lld -o %t --script %t.script %t.o
 # RUN: llvm-readobj -sections %t | FileCheck %s --check-prefix=NONALLOC