[lld] [lld][NFC] Precommit test for ld -r links FatLTO PIC objects (PR #92817)

[Paul Kirth via llvm-commits]

https://github.com/ilovepi created https://github.com/llvm/llvm-project/pull/92817

Currently, with PIC relocatable links, FatLTO sections are treated as orphan
sections and incorrectly concatenated together. This test verifies the current
behavior, but should be fixed to either merge those sections into a single llvm
module, similar to what `llvm-link` would produce, or to drop them altogether.


>From 7ae42667cab825e3a89df9b8ebff1b37dc155f79 Mon Sep 17 00:00:00 2001
From: Paul Kirth <paulkirth at google.com>
Date: Mon, 20 May 2024 13:48:00 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.4
---
 lld/test/ELF/fatlto/fatlto.test | 41 +++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/lld/test/ELF/fatlto/fatlto.test b/lld/test/ELF/fatlto/fatlto.test
index edf4ef2da2b88..2b9c41d5f5587 100644
--- a/lld/test/ELF/fatlto/fatlto.test
+++ b/lld/test/ELF/fatlto/fatlto.test
@@ -49,6 +49,25 @@
 ; RUN: ld.lld -o %t/foo-fatLTO.archive %t/a.a %t/main-LTO.bc --fat-lto-objects
 ; RUN: cmp %t/foo-fatLTO.archive %t/foo-LTO
 
+;; Test FatLTO works with relocatable links using PIC objects
+;; Currently, with PIC relocatable links, FatLTO sections are treated as
+;; orphan sections and incorrectly concatenated together. This test verifies
+;; the current behavior, but should be fixed to either merge those sections
+;; correctly, or to drop them altogether.
+; RUN: opt < %t/a-LTO.ll -passes="embed-bitcode<thinlto;emit-summary>" | llc --relocation-model=pic --filetype=obj -o %t/a-fat-pic.o
+; RUN: llvm-readobj -S %t/a-fat-pic.o | FileCheck --check-prefix=HAS_LLVM_LTO %s
+
+; RUN: opt < %t/b-LTO.ll -passes="embed-bitcode<thinlto;emit-summary>" | llc --relocation-model=pic --filetype=obj -o %t/b-fat-pic.o
+; RUN: llvm-readobj -S %t/b-fat-pic.o | FileCheck --check-prefix=HAS_LLVM_LTO %s
+
+; RUN: llvm-ar rcs %t/fat.archive %t/a-fat-pic.o %t/b-fat-pic.o
+; RUN: llvm-readobj -S %t/fat.pic.archive | FileCheck --check-prefix=HAS_LLVM_LTO %s
+
+; RUN: ld.lld --whole-archive %t/fat.pic.archive -r -o %t/fat-relocatable.o
+; RUN: llvm-readobj -S %t/fat-pic-relocatable.o | FileCheck --check-prefix=HAS_LLVM_LTO %s
+
+; HAS_LLVM_LTO: Name: .llvm.lto
+
 ;--- a-LTO.ll
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
@@ -71,6 +90,28 @@ attributes #0 = { noinline nounwind uwtable }
 !5 = !{i32 1, !"ThinLTO", i32 0}
 !6 = !{i32 1, !"EnableSplitLTOUnit", i32 1}
 
+;--- b-LTO.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind uwtable
+define dso_local i32 @foo() #0 {
+entry:
+  ret i32 0
+}
+
+attributes #0 = { noinline nounwind uwtable }
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 7, !"PIC Level", i32 2}
+!2 = !{i32 7, !"PIE Level", i32 2}
+!3 = !{i32 7, !"uwtable", i32 2}
+!4 = !{i32 7, !"frame-pointer", i32 2}
+!5 = !{i32 1, !"ThinLTO", i32 0}
+!6 = !{i32 1, !"EnableSplitLTOUnit", i32 1}
+
 ;--- main-LTO.ll
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"