| From 3ccd041af920125595a992becd0e1e4083ce562b Mon Sep 17 00:00:00 2001 |
| From: Nick Desaulniers <ndesaulniers@google.com> |
| Date: Wed, 27 Oct 2021 11:36:23 -0700 |
| Subject: [PATCH] [LowerTypeTests] Emit cfi_jt aliases regardless of function |
| export |
| |
| A constant complaint we get is that the __typeid__ symbols in the CFI |
| jump tables causes confusing stack traces in applications. Emit the more |
| readable cfi_jt aliases regardless of function export (LTO vs Thin LTO). |
| |
| Reviewed By: pcc, tejohnson |
| |
| Differential Revision: https://reviews.llvm.org/D107934 |
| --- |
| llvm/lib/Transforms/IPO/LowerTypeTests.cpp | 27 +++-- |
| llvm/test/LTO/X86/cfi_jt_aliases.ll | 112 +++++++++++++++++++++ |
| 2 files changed, 131 insertions(+), 8 deletions(-) |
| create mode 100644 llvm/test/LTO/X86/cfi_jt_aliases.ll |
| |
| diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp |
| index 340baff90904..26aa858cb827 100644 |
| --- a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp |
| +++ b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp |
| @@ -1561,17 +1561,28 @@ void LowerTypeTestsModule::buildBitSetsFromFunctionsNative( |
| ArrayRef<Constant *>{ConstantInt::get(IntPtrTy, 0), |
| ConstantInt::get(IntPtrTy, I)}), |
| F->getType()); |
| - if (Functions[I]->isExported()) { |
| - if (IsJumpTableCanonical) { |
| - ExportSummary->cfiFunctionDefs().insert(std::string(F->getName())); |
| - } else { |
| - GlobalAlias *JtAlias = GlobalAlias::create( |
| - F->getValueType(), 0, GlobalValue::ExternalLinkage, |
| - F->getName() + ".cfi_jt", CombinedGlobalElemPtr, &M); |
| + |
| + const bool IsExported = Functions[I]->isExported(); |
| + if (!IsJumpTableCanonical) { |
| + GlobalValue::LinkageTypes LT = IsExported |
| + ? GlobalValue::ExternalLinkage |
| + : GlobalValue::InternalLinkage; |
| + GlobalAlias *JtAlias = GlobalAlias::create(F->getValueType(), 0, LT, |
| + F->getName() + ".cfi_jt", |
| + CombinedGlobalElemPtr, &M); |
| + if (IsExported) |
| JtAlias->setVisibility(GlobalValue::HiddenVisibility); |
| + else |
| + appendToUsed(M, {JtAlias}); |
| + } |
| + |
| + if (IsExported) { |
| + if (IsJumpTableCanonical) |
| + ExportSummary->cfiFunctionDefs().insert(std::string(F->getName())); |
| + else |
| ExportSummary->cfiFunctionDecls().insert(std::string(F->getName())); |
| - } |
| } |
| + |
| if (!IsJumpTableCanonical) { |
| if (F->hasExternalWeakLinkage()) |
| replaceWeakDeclarationWithJumpTablePtr(F, CombinedGlobalElemPtr, |
| diff --git a/llvm/test/LTO/X86/cfi_jt_aliases.ll b/llvm/test/LTO/X86/cfi_jt_aliases.ll |
| new file mode 100644 |
| index 000000000000..d5d85d0dcbd3 |
| --- /dev/null |
| +++ b/llvm/test/LTO/X86/cfi_jt_aliases.ll |
| @@ -0,0 +1,112 @@ |
| +; Full LTO test |
| +; RUN: opt %s -o %t.bc |
| +; RUN: llvm-lto2 run -o %t.o %t.bc -save-temps \ |
| +; RUN: -r=%t.bc,a,px \ |
| +; RUN: -r=%t.bc,b,px \ |
| +; RUN: -r=%t.bc,c,px \ |
| +; RUN: -r=%t.bc,d,px |
| +; RUN: llvm-readelf --symbols %t.o.0 | grep \.cfi_jt | FileCheck --check-prefix=CHECK-FULL-RE %s |
| +; RUN: llvm-objdump -dr %t.o.0 | FileCheck --check-prefix=CHECK-FULL-OD %s |
| +; RUN: llvm-dis %t.o.0.4.opt.bc -o - | FileCheck --check-prefix=CHECK-USED %s |
| +; Thin LTO test |
| +; RUN: opt -thinlto-bc -thinlto-split-lto-unit %s -o %t.bc |
| +; RUN: llvm-lto2 run -o %t.o %t.bc \ |
| +; RUN: -r=%t.bc,a,px \ |
| +; RUN: -r=%t.bc,b,px \ |
| +; RUN: -r=%t.bc,c,px \ |
| +; RUN: -r=%t.bc,d,px |
| +; RUN: llvm-readelf --symbols %t.o.0 | grep \.cfi_jt | FileCheck --check-prefix=CHECK-THIN-RE %s |
| +; RUN: llvm-objdump -dr %t.o.0 | FileCheck --check-prefix=CHECK-THIN-OD %s |
| + |
| +; CHECK-FULL-RE: FUNC LOCAL DEFAULT {{[0-9]+}} a.cfi_jt |
| +; CHECK-FULL-RE-NEXT: FUNC LOCAL DEFAULT {{[0-9]+}} b.cfi_jt |
| +; CHECK-FULL-RE-NEXT: FUNC LOCAL DEFAULT {{[0-9]+}} c.cfi_jt |
| + |
| +; CHECK-THIN-RE: FUNC GLOBAL HIDDEN {{[0-9]+}} b.cfi_jt |
| +; CHECK-THIN-RE-NEXT: FUNC GLOBAL HIDDEN {{[0-9]+}} c.cfi_jt |
| +; CHECK-THIN-RE-NEXT: FUNC GLOBAL HIDDEN {{[0-9]+}} a.cfi_jt |
| + |
| +; CHECK-FULL-OD: a.cfi_jt>: |
| +; CHECK-FULL-OD: jmp {{.*}} <a.cfi_jt |
| +; CHECK-FULL-OD-NEXT: R_X86_64_PLT32 .La$local |
| +; CHECK-FULL-OD: b.cfi_jt>: |
| +; CHECK-FULL-OD: jmp {{.*}} <b.cfi_jt |
| +; CHECK-FULL-OD-NEXT: R_X86_64_PLT32 .Lb$local |
| +; CHECK-FULL-OD: c.cfi_jt>: |
| +; CHECK-FULL-OD: jmp {{.*}} <c.cfi_jt |
| +; CHECK-FULL-OD-NEXT: R_X86_64_PLT32 .Lc$local |
| + |
| +; CHECK-THIN-OD: b.cfi_jt>: |
| +; CHECK-THIN-OD: jmp {{.*}} <b.cfi_jt |
| +; CHECK-THIN-OD-NEXT: R_X86_64_PLT32 b |
| +; CHECK-THIN-OD: c.cfi_jt>: |
| +; CHECK-THIN-OD: jmp {{.*}} <c.cfi_jt |
| +; CHECK-THIN-OD-NEXT: R_X86_64_PLT32 c |
| +; CHECK-THIN-OD: a.cfi_jt>: |
| +; CHECK-THIN-OD: jmp {{.*}} <a.cfi_jt |
| +; CHECK-THIN-OD-NEXT: R_X86_64_PLT32 a |
| + |
| +; CHECK-USED: @llvm.used = appending global [3 x i8*] [i8* bitcast (void ()* @a.cfi_jt to i8*), i8* bitcast (void ()* @b.cfi_jt to i8*), i8* bitcast (void ()* @c.cfi_jt to i8*)], section "llvm.metadata" |
| + |
| +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" |
| + |
| +@f = internal global [4 x void ()*] [void ()* @a, void ()* @b, void ()* @c, void ()* null], align 16 |
| + |
| +define dso_local void @a() !type !5 !type !6 { ret void } |
| +define dso_local void @b() !type !5 !type !6 { ret void } |
| +define dso_local void @c() !type !5 !type !6 { ret void } |
| + |
| +define dso_local void @d() !type !5 !type !6 { |
| +entry: |
| + %i = alloca i32, align 4 |
| + store i32 0, i32* %i, align 4 |
| + br label %for.cond |
| + |
| +for.cond: ; preds = %for.inc, %entry |
| + %0 = load i32, i32* %i, align 4 |
| + %idxprom = sext i32 %0 to i64 |
| + %arrayidx = getelementptr inbounds [4 x void ()*], [4 x void ()*]* @f, i64 0, i64 %idxprom |
| + %1 = load void ()*, void ()** %arrayidx, align 8 |
| + %tobool = icmp ne void ()* %1, null |
| + br i1 %tobool, label %for.body, label %for.end |
| + |
| +for.body: ; preds = %for.cond |
| + %2 = load i32, i32* %i, align 4 |
| + %idxprom1 = sext i32 %2 to i64 |
| + %arrayidx2 = getelementptr inbounds [4 x void ()*], [4 x void ()*]* @f, i64 0, i64 %idxprom1 |
| + %3 = load void ()*, void ()** %arrayidx2, align 8 |
| + %4 = bitcast void ()* %3 to i8*, !nosanitize !7 |
| + %5 = call i1 @llvm.type.test(i8* %4, metadata !"_ZTSFvvE"), !nosanitize !7 |
| + br i1 %5, label %cont, label %trap, !nosanitize !7 |
| + |
| +trap: ; preds = %for.body |
| + call void @llvm.ubsantrap(i8 2), !nosanitize !7 |
| + unreachable, !nosanitize !7 |
| + |
| +cont: ; preds = %for.body |
| + call void %3() |
| + br label %for.inc |
| + |
| +for.inc: ; preds = %cont |
| + %6 = load i32, i32* %i, align 4 |
| + %inc = add nsw i32 %6, 1 |
| + store i32 %inc, i32* %i, align 4 |
| + br label %for.cond |
| + |
| +for.end: ; preds = %for.cond |
| + ret void |
| +} |
| + |
| +declare i1 @llvm.type.test(i8*, metadata) |
| +declare void @llvm.ubsantrap(i8 immarg) |
| + |
| +!llvm.module.flags = !{!0, !1, !2, !3} |
| + |
| +!0 = !{i32 1, !"wchar_size", i32 4} |
| +!1 = !{i32 4, !"CFI Canonical Jump Tables", i32 0} |
| +!2 = !{i32 7, !"uwtable", i32 1} |
| +!3 = !{i32 7, !"frame-pointer", i32 2} |
| +!5 = !{i64 0, !"_ZTSFvvE"} |
| +!6 = !{i64 0, !"_ZTSFvvE.generalized"} |
| +!7 = !{} |
| -- |
| 2.33.0.1079.g6e70778dc9-goog |
| |
