release/19.x: [lld] select a default eflags for hexagon (#108431)

[llvmbot]

Backport d1ba432

Requested by: @androm3da

[llvmbot]

@quic-akaryaki What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-lld
@llvm/pr-subscribers-backend-hexagon

@llvm/pr-subscribers-lld-elf

Author: None (llvmbot)

Changes

Backport d1ba432

Requested by: @androm3da

---

Full diff: https://github.com/llvm/llvm-project/pull/108661.diff

2 Files Affected:

• (modified) lld/ELF/Arch/Hexagon.cpp (+3-5)
• (modified) lld/test/ELF/hexagon-eflag.s (+5)

diff --git a/lld/ELF/Arch/Hexagon.cpp b/lld/ELF/Arch/Hexagon.cpp
index 54821c299bde9e..abde3cd964917e 100644
--- a/lld/ELF/Arch/Hexagon.cpp
+++ b/lld/ELF/Arch/Hexagon.cpp
@@ -60,17 +60,15 @@ Hexagon::Hexagon() {
 }
 
 uint32_t Hexagon::calcEFlags() const {
-  assert(!ctx.objectFiles.empty());
-
   // The architecture revision must always be equal to or greater than
   // greatest revision in the list of inputs.
-  uint32_t ret = 0;
+  std::optional<uint32_t> ret;
   for (InputFile *f : ctx.objectFiles) {
     uint32_t eflags = cast<ObjFile<ELF32LE>>(f)->getObj().getHeader().e_flags;
-    if (eflags > ret)
+    if (!ret || eflags > *ret)
       ret = eflags;
   }
-  return ret;
+  return ret.value_or(/* Default Arch Rev: */ 0x60);
 }
 
 static uint32_t applyMask(uint32_t mask, uint32_t data) {
diff --git a/lld/test/ELF/hexagon-eflag.s b/lld/test/ELF/hexagon-eflag.s
index 01cb5e5b0f2935..dbe8604f69fda3 100644
--- a/lld/test/ELF/hexagon-eflag.s
+++ b/lld/test/ELF/hexagon-eflag.s
@@ -5,3 +5,8 @@
 # RUN: llvm-readelf -h  %t3 | FileCheck %s
 # Verify that the largest arch in the input list is selected.
 # CHECK: Flags: 0x62
+
+# RUN: llvm-ar rcsD %t4
+# RUN: ld.lld -m hexagonelf %t4 -o %t5
+# RUN: llvm-readelf -h  %t5 | FileCheck --check-prefix=CHECK-EMPTYARCHIVE %s
+# CHECK-EMPTYARCHIVE: Flags: 0x60

[MaskRay]

LGTM

[github-actions]

@androm3da (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.