diff options
| -rw-r--r-- | llvm/lib/LTO/LTOBackend.cpp | 21 | ||||
| -rw-r--r-- | llvm/test/ThinLTO/X86/deadstrip.ll | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/PGOProfile/thinlto_samplepgo_icp_droppeddead.ll | 71 | ||||
| -rw-r--r-- | llvm/test/tools/gold/X86/global_with_section.ll | 6 |
4 files changed, 90 insertions, 10 deletions
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp index 49c0c2e15b3..4dbdd26be9d 100644 --- a/llvm/lib/LTO/LTOBackend.cpp +++ b/llvm/lib/LTO/LTOBackend.cpp @@ -401,14 +401,23 @@ Error lto::backend(Config &C, AddStreamFn AddStream, static void dropDeadSymbols(Module &Mod, const GVSummaryMapTy &DefinedGlobals, const ModuleSummaryIndex &Index) { - std::vector<GlobalValue *> ReplacedGlobals; + std::vector<GlobalValue*> DeadGVs; for (auto &GV : Mod.global_values()) if (GlobalValueSummary *GVS = DefinedGlobals.lookup(GV.getGUID())) - if (!Index.isGlobalValueLive(GVS) && !convertToDeclaration(GV)) - ReplacedGlobals.push_back(&GV); - - for (GlobalValue *GV : ReplacedGlobals) - GV->eraseFromParent(); + if (!Index.isGlobalValueLive(GVS)) { + DeadGVs.push_back(&GV); + convertToDeclaration(GV); + } + + // Now that all dead bodies have been dropped, delete the actual objects + // themselves when possible. + for (GlobalValue *GV : DeadGVs) { + GV->removeDeadConstantUsers(); + // Might reference something defined in native object (i.e. dropped a + // non-prevailing IR def, but we need to keep the declaration). + if (GV->use_empty()) + GV->eraseFromParent(); + } } Error lto::thinBackend(Config &Conf, unsigned Task, AddStreamFn AddStream, diff --git a/llvm/test/ThinLTO/X86/deadstrip.ll b/llvm/test/ThinLTO/X86/deadstrip.ll index f1a587359c8..e3f16a8e0b3 100644 --- a/llvm/test/ThinLTO/X86/deadstrip.ll +++ b/llvm/test/ThinLTO/X86/deadstrip.ll @@ -50,7 +50,7 @@ ; LTO2: define internal void @_GLOBAL__I_a() ; LTO2: define internal void @bar() { ; LTO2: define internal void @bar_internal() -; LTO2: declare dso_local void @dead_func() +; LTO2-NOT: @dead_func() ; LTO2-NOT: available_externally {{.*}} @baz() ; Make sure we didn't internalize @boo, which is reachable via diff --git a/llvm/test/Transforms/PGOProfile/thinlto_samplepgo_icp_droppeddead.ll b/llvm/test/Transforms/PGOProfile/thinlto_samplepgo_icp_droppeddead.ll new file mode 100644 index 00000000000..fcbc2d64541 --- /dev/null +++ b/llvm/test/Transforms/PGOProfile/thinlto_samplepgo_icp_droppeddead.ll @@ -0,0 +1,71 @@ +; REQUIRES: x86-registered-target + +; RUN: opt -module-summary %s -o %t.bc + +; Tests that with dead stripping in the thin link enabled (default), we do not +; promote to target of the dropped dead symbol _ZL3foov. This can happen with a +; sample profile collected for one binary used to optimize for another binary. +; RUN: llvm-lto2 run -save-temps -o %t2 %t.bc -r %t.bc,fptr,plx \ +; RUN: -r %t.bc,main,plx -r %t.bc,_ZL3foov,l +; RUN: llvm-dis < %t2.1.4.opt.bc | FileCheck %s --check-prefix=OPT +; RUN: llvm-lto2 run -save-temps -o %t2 %t.bc -r %t.bc,fptr,plx \ +; RUN: -r %t.bc,main,plx -r %t.bc,_ZL3foov,l -compute-dead=false +; RUN: llvm-dis < %t2.1.4.opt.bc | FileCheck %s --check-prefix=OPT-NODEAD + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +@fptr = local_unnamed_addr global void ()* null, align 8 + +define void @_ZL3foov() #1 { +entry: + ret void +} + +define i32 @main() local_unnamed_addr #0 !prof !34 { +entry: + %0 = load void ()*, void ()** @fptr, align 8 +; OPT-NOT: label %if.false.orig_indirect +; OPT-NODEAD: br i1 %{{[0-9]+}}, label %if.end.icp, label %if.false.orig_indirect + tail call void %0(), !prof !40 + ret i32 0 +} + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!3,!4} +!llvm.ident = !{!31} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 5.0.0 (trunk 297016)", isOptimized: true, runtimeVersion: 0, emissionKind: NoDebug, enums: !2) +!1 = !DIFile(filename: "main.cc", directory: ".") +!2 = !{} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = !{i32 1, !"ProfileSummary", !5} +!5 = !{!6, !7, !8, !9, !10, !11, !12, !13} +!6 = !{!"ProfileFormat", !"SampleProfile"} +!7 = !{!"TotalCount", i64 3003} +!8 = !{!"MaxCount", i64 3000} +!9 = !{!"MaxInternalCount", i64 0} +!10 = !{!"MaxFunctionCount", i64 0} +!11 = !{!"NumCounts", i64 3} +!12 = !{!"NumFunctions", i64 1} +!13 = !{!"DetailedSummary", !14} +!14 = !{!15, !16, !17, !18, !19, !20, !20, !21, !21, !22, !23, !24, !25, !26, !27, !28, !29, !30} +!15 = !{i32 10000, i64 3000, i32 1} +!16 = !{i32 100000, i64 3000, i32 1} +!17 = !{i32 200000, i64 3000, i32 1} +!18 = !{i32 300000, i64 3000, i32 1} +!19 = !{i32 400000, i64 3000, i32 1} +!20 = !{i32 500000, i64 3000, i32 1} +!21 = !{i32 600000, i64 3000, i32 1} +!22 = !{i32 700000, i64 3000, i32 1} +!23 = !{i32 800000, i64 3000, i32 1} +!24 = !{i32 900000, i64 3000, i32 1} +!25 = !{i32 950000, i64 3000, i32 1} +!26 = !{i32 990000, i64 3000, i32 1} +!27 = !{i32 999000, i64 3000, i32 1} +!28 = !{i32 999900, i64 2, i32 2} +!29 = !{i32 999990, i64 2, i32 2} +!30 = !{i32 999999, i64 2, i32 2} +!31 = !{!"clang version 5.0.0 (trunk 297016)"} +!34 = !{!"function_entry_count", i64 1} +!40 = !{!"VP", i32 0, i64 3000, i64 -8789629626369651636, i64 3000} diff --git a/llvm/test/tools/gold/X86/global_with_section.ll b/llvm/test/tools/gold/X86/global_with_section.ll index 8ea4246c49c..2ba0a16e237 100644 --- a/llvm/test/tools/gold/X86/global_with_section.ll +++ b/llvm/test/tools/gold/X86/global_with_section.ll @@ -47,7 +47,7 @@ target triple = "x86_64-unknown-linux-gnu" ; the expected internalization. ; CHECK-REGULARLTO-DAG: @var_with_nonC_section = internal global i32 0, section ".nonCsection" ; Check we dropped definition of dead variable. -; CHECK-THINLTO-DAG: @var_with_nonC_section = external dso_local global i32, section ".nonCsection" +; CHECK-THINLTO-NOT: @var_with_nonC_section @var_with_nonC_section = global i32 0, section ".nonCsection" ; We should not internalize @deadfunc_with_section due to section @@ -61,7 +61,7 @@ define void @deadfunc_with_section() section "some_other_section" { ; the expected internalization. ; CHECK2-REGULARLTO-DAG: define internal void @deadfunc_with_nonC_section() section ".nonCsection" ; Check dead function converted to declaration. -; CHECK-THINLTO-DAG: declare dso_local void @deadfunc_with_nonC_section() section ".nonCsection" +; CHECK-THINLTO-NOT: @deadfunc_with_nonC_section() define void @deadfunc_with_nonC_section() section ".nonCsection" { call void @deadfunc2_called_from_nonC_section() ret void @@ -80,5 +80,5 @@ declare void @deadfunc2_called_from_section() ; are getting the expected internalization. ; CHECK2-REGULARLTO: define internal void @deadfunc2_called_from_nonC_section ; Check dead function converted to declaration. -; CHECK2-THINLTO: declare dso_local void @deadfunc2_called_from_nonC_section +; CHECK2-THINLTO-NOT: @deadfunc2_called_from_nonC_section declare void @deadfunc2_called_from_nonC_section() |
