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1; REQUIRES: arm2;; Test for LTO optimizing out references to symbols that are pulled in by3;; compiler-generated libcalls (post LTO).4;; Lazy files extracted post LTO compilation might reference other lazy files.5;; Referenced relocatable files are extracted and everything works as intended.6;; However, if the referenced lazy file is a bitcode file, no further LTO7;; compilation occurs. lld currently treats any symbols from that bitcode file8;; as absolute, which leads to a "refer to absolute symbol" error in PIC links9;; and leads to silently broken output. For example, lazy aeabi_ldivmod.o post10;; LTO extraction might call __divmoddi4 defined in an unextracted lazy bitcode11;; file (https://github.com/llvm/llvm-project/issues/127284).12; RUN: rm -rf %t && split-file %s %t && cd %t13; RUN: llvm-as divmoddi4.ll -o divmoddi4.bc14; RUN: llvm-mc -filetype=obj -triple=armv7-none-unknown-eabi aeabi_ldivmod.s -o aeabi_ldivmod.o15;; With an explicit __aebi_ldivmod call in the input IR this works as expected:16; RUN: llvm-as main-explicit.ll -o main-explicit-ldivmod.bc17; RUN: ld.lld main-explicit-ldivmod.bc --start-lib aeabi_ldivmod.o divmoddi4.bc --end-lib -o out.explicit18; RUN: llvm-objdump -d -r -t out.explicit | FileCheck %s --check-prefix=GOOD-DUMP19; GOOD-DUMP-LABEL: SYMBOL TABLE:20; GOOD-DUMP: [[#]] g F .text 00000024 __aeabi_ldivmod21; GOOD-DUMP: [[#]] g F .text [[#]] __divmoddi422; GOOD-DUMP-LABEL: <__aeabi_ldivmod>:23; GOOD-DUMP: bl 0x20140 <__divmoddi4> @ imm = #0x2824 25;; But if the call is generated by ISel, we end up with an invalid reference:26; RUN: llvm-as main-implicit.ll -o main-implicit-ldivmod.bc27; RUN: ld.lld main-implicit-ldivmod.bc --start-lib aeabi_ldivmod.o divmoddi4.bc --end-lib -o out.implicit28; RUN: llvm-objdump -d -r -t out.implicit | FileCheck %s --check-prefix=BAD-DUMP29;; We jump to address zero here and __divmoddi4 ends up being an absolute symbol:30; BAD-DUMP-LABEL: SYMBOL TABLE:31; BAD-DUMP: [[#]] g F .text 00000024 __aeabi_ldivmod32; BAD-DUMP: [[#]] g *ABS* 00000000 __divmoddi433; BAD-DUMP-LABEL: <__aeabi_ldivmod>:34; BAD-DUMP: bl 0x0 <__divmoddi4>35;; Linking with -pie complains about the invalid relocation (and even points back to the source files)36; RUN: not ld.lld main-implicit-ldivmod.bc --start-lib aeabi_ldivmod.o divmoddi4.bc --end-lib -o out.pie --no-undefined -pie --no-dynamic-linker 2>&1 | FileCheck %s --check-prefix=PIE-ERROR37PIE-ERROR: ld.lld: error: relocation R_ARM_CALL cannot refer to absolute symbol: __divmoddi438PIE-ERROR-NEXT: >>> defined in divmoddi4.bc39PIE-ERROR-NEXT: >>> referenced by aeabi_ldivmod.o:(__aeabi_ldivmod)40;; Removing --start-lib/--end-lib also ensures that the reference is retained41; RUN: ld.lld main-implicit-ldivmod.bc aeabi_ldivmod.o divmoddi4.bc -o out.nolib42; RUN: llvm-objdump -d -r -t out.nolib | FileCheck %s --check-prefix=GOOD-DUMP43 44;; Interestingly, just declaring __aeabi_ldivmod is sufficient to not run into this issue.45; RUN: llvm-as main-declared.ll -o main-declared-ldivmod.bc46; RUN: ld.lld main-declared-ldivmod.bc --start-lib aeabi_ldivmod.o divmoddi4.bc --end-lib -o out.declared47; RUN: llvm-objdump -d -r -t out.declared | FileCheck %s --check-prefix=GOOD-DUMP48 49;--- divmoddi4.ll50target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"51target triple = "armv7-none-unknown-eabi"52 53; Adding it to llvm.used does not appears to have any effect!54;; @llvm.used = appending global [1 x ptr] [ptr @__divmoddi4], section "llvm.metadata"55 56; Stub version of the real __divmoddi457define i64 @__divmoddi4(i64 %a, i64 %b, ptr writeonly %rem) #0 align 32 {58entry:59 %sub = sub i64 %a, %b60 store i64 0, ptr %rem, align 861 ret i64 %sub62}63 64attributes #0 = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(argmem: write) "frame-pointer"="non-leaf" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a15" }65 66;--- aeabi_ldivmod.s67.syntax unified68.p2align 269.arm70.globl __aeabi_ldivmod71.type __aeabi_ldivmod,%function72__aeabi_ldivmod:73 push {r6, lr}74 sub sp, sp, #1675 add r6, sp, #876 str r6, [sp]77 bl __divmoddi478 ldr r2, [sp, #8]79 ldr r3, [sp, #12]80 add sp, sp, #1681 pop {r6, pc}82.size __aeabi_ldivmod, . - __aeabi_ldivmod83 84;--- main-implicit.ll85target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"86target triple = "armv7-none-unknown-eabi"87 88define dso_local i64 @_start(i64 %num, i64 %denom) local_unnamed_addr #0 {89entry:90 %div = sdiv i64 %num, %denom91 %ret = add i64 %div, 292 ret i64 %ret93}94 95attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a15" }96 97;--- main-explicit.ll98target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"99target triple = "armv7-none-unknown-eabi"100 101declare { i64, i64 } @__aeabi_ldivmod(i64, i64)102 103define dso_local noundef i64 @_start(i64 noundef %num, i64 noundef %denom) local_unnamed_addr #0 {104entry:105 %quotrem = call { i64, i64 } @__aeabi_ldivmod(i64 %num, i64 %denom)106 %div = extractvalue { i64, i64 } %quotrem, 0107 %ret = add i64 %div, 2108 ret i64 %ret109}110 111attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a15" }112 113;--- main-declared.ll114target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"115target triple = "armv7-none-unknown-eabi"116 117declare { i64, i64 } @__aeabi_ldivmod(i64, i64)118 119define dso_local i64 @_start(i64 %num, i64 %denom) local_unnamed_addr #0 {120entry:121 %div = sdiv i64 %num, %denom122 %ret = add i64 %div, 2123 ret i64 %ret124}125 126attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a15" }127