[lld][test] Precommit test for ld -r links with FatLTO PIC objects (#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.

Author: ilovepi

lld/test/ELF/fatlto/fatlto.test

@@ -1,53 +1,79 @@
 ;; Basic FatLTO tests.
 ; REQUIRES: x86
 
-; RUN: rm -rf %t && split-file %s %t
+; RUN: rm -rf %t && split-file %s %t && cd %t
 
 ;; Ensure that input files contain .llvm.lto section.
-; RUN: llc %t/a-LTO.ll --filetype=obj -o %t/a-fatLTO.o
-; RUN: opt < %t/a-LTO.ll --module-summary -o %t/a-fatLTO.bc
-; RUN: llvm-objcopy --add-section=.llvm.lto=%t/a-fatLTO.bc --set-section-flags=.llvm.lto=exclude %t/a-fatLTO.o
+; RUN: llc a-LTO.ll --filetype=obj -o a-fatLTO.o --relocation-model=pic
+; RUN: opt < a-LTO.ll --module-summary -o a-fatLTO.bc
+; RUN: llvm-objcopy --add-section=.llvm.lto=a-fatLTO.bc --set-section-flags=.llvm.lto=exclude --set-section-type=.llvm.lto=0x6fff4c0c a-fatLTO.o
 
-; RUN: llc %t/main-LTO.ll --filetype=obj -o %t/main-fatLTO.o
-; RUN: opt < %t/main-LTO.ll --module-summary -o %t/main-fatLTO.bc
-; RUN: llvm-objcopy --add-section=.llvm.lto=%t/main-fatLTO.bc --set-section-flags=.llvm.lto=exclude %t/main-fatLTO.o
+
+; RUN: llc main-LTO.ll --filetype=obj -o main-fatLTO.o --relocation-model=pic
+; RUN: opt < main-LTO.ll --module-summary -o main-fatLTO.bc
+; RUN: llvm-objcopy --add-section=.llvm.lto=main-fatLTO.bc --set-section-flags=.llvm.lto=exclude --set-section-type=.llvm.lto=0x6fff4c0c main-fatLTO.o
+
+; RUN: llvm-readelf -S a-fatLTO.o | FileCheck --check-prefix=HAS_LLVM_LTO %s
+; RUN: llvm-readelf -S main-fatLTO.o | FileCheck --check-prefix=HAS_LLVM_LTO %s
+
+;; Make sure that the section flags are set correctly
+; HA_LLVM_LTO: Name: .llvm.lto
+; HA_LLVM_LTO-NEXT: Type: SHT_LLVM_LTO
+; HA_LLVM_LTO-NEXT: Flags
+; HA_LLVM_LTO-NEXT: SHF_EXCLUDE
+
+; HAS_LLVM_LTO: Name Type Address Off Size ES Flg Lk Inf Al
+; HAS_LLVM_LTO: .llvm.lto LLVM_LTO {{.*}} 00  WE  0   0  1
 
 ;; Final executable should not have .llvm.lto section no matter what the target is.
-; RUN: ld.lld -o %t/foo-fatLTO %t/a-fatLTO.o %t/main-fatLTO.o --fat-lto-objects
-; RUN: llvm-readobj -S %t/foo-fatLTO | FileCheck --check-prefix=CHECK-LTO-TARGET %s
+; RUN: ld.lld -o foo-fatLTO a-fatLTO.o main-fatLTO.o --fat-lto-objects
+; RUN: llvm-readelf -S foo-fatLTO | FileCheck --check-prefix=CHECK-LTO-TARGET %s
 
 ;; Check that fat objects work w/ --start-lib.
-; RUN: ld.lld -o %t/foo-fatLTO.start_lib --start-lib %t/a-fatLTO.o %t/main-fatLTO.o --fat-lto-objects
-; RUN: llvm-readobj -S %t/foo-fatLTO.start_lib | FileCheck --check-prefix=CHECK-LTO-TARGET %s
+; RUN: ld.lld -o foo-fatLTO.start_lib --start-lib a-fatLTO.o main-fatLTO.o --fat-lto-objects
+; RUN: llvm-readelf -S foo-fatLTO.start_lib | FileCheck --check-prefix=CHECK-LTO-TARGET %s
 
 ;; Check if .llvm.lto section gets aggregated in LTO target.
-; CHECK-LTO-TARGET-NOT: Name: .llvm.lto
+; CHECK-LTO-TARGET: Name Type Address Off Size ES Flg Lk Inf Al
+; CHECK-LTO-TARGET-NOT: .llvm.lto
 
 ;; Final executable should not have .llvm.lto section no matter what the target is.
-; RUN: ld.lld -o %t/foo-fatNoLTO %t/a-fatLTO.o %/t/main-fatLTO.o
-; RUN: llvm-readobj -S %t/foo-fatNoLTO | FileCheck --check-prefix=CHECK-NON-LTO-TARGET %s
+; RUN: ld.lld -o foo-fatNoLTO a-fatLTO.o %/t/main-fatLTO.o
+; RUN: llvm-readelf -S foo-fatNoLTO | FileCheck --check-prefix=CHECK-NON-LTO-TARGET %s
 
 ;; Check if .llvm.lto section gets aggregated in non-LTO target.
-; CHECK-NON-LTO-TARGET-NOT: Name: .llvm.lto
+; CHECK-NON-LTO-TARGET: Name Type Address Off Size ES Flg Lk Inf Al
+; CHECK-NON-LTO-TARGET-NOT: .llvm.lto
 
 ;; Check if the LTO target executable produced from FatLTO object file is
 ;; identical to the one produced from LTO modules.
-; RUN: opt < %t/a-LTO.ll --module-summary -o %t/a-LTO.bc
-; RUN: opt < %t/main-LTO.ll --module-summary -o %t/main-LTO.bc
-; RUN: ld.lld -o %t/foo-LTO %t/a-LTO.bc %t/main-LTO.bc
-; RUN: cmp %t/foo-fatLTO %t/foo-LTO
+; RUN: opt < a-LTO.ll --module-summary -o a-LTO.bc
+; RUN: opt < main-LTO.ll --module-summary -o main-LTO.bc
+; RUN: ld.lld -o foo-LTO a-LTO.bc main-LTO.bc
+; RUN: cmp foo-fatLTO foo-LTO
 
 ;; Check if the no-LTO target executable produced from FatLTO object file is
 ;; identical to the one produced from regular object files.
-; RUN: llc %t/a-LTO.ll --filetype=obj -o %t/a.o
-; RUN: llc %t/main-LTO.ll --filetype=obj -o %t/main.o
-; RUN: ld.lld -o %t/foo-noLTO %t/a.o %t/main.o
-; RUN: cmp %t/foo-fatNoLTO %t/foo-noLTO
+; RUN: llc a-LTO.ll --filetype=obj -o a.o
+; RUN: llc main-LTO.ll --filetype=obj -o main.o
+; RUN: ld.lld -o foo-noLTO a.o main.o
+; RUN: cmp foo-fatNoLTO foo-noLTO
 
 ;; Check archive support.
-; RUN: llvm-ar rcs %t/a.a %t/a-fatLTO.o 
-; 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
+; RUN: llvm-ar rcs a.a a-fatLTO.o 
+; RUN: ld.lld -o foo-fatLTO.archive a.a main-LTO.bc --fat-lto-objects
+; RUN: cmp foo-fatLTO.archive 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: llvm-ar rcs fatLTO-pic.a a-fatLTO.o main-fatLTO.o
+; RUN: llvm-readelf -S fatLTO-pic.a | FileCheck --check-prefix=HAS_LLVM_LTO %s
+
+; RUN: ld.lld --whole-archive fatLTO-pic.a -r -o fatLTO-pic-reolcatable.o
+; RUN: llvm-readelf -S fatLTO-pic-reolcatable.o | FileCheck --check-prefix=HAS_LLVM_LTO %s
 
 ;--- 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"