[llvm] 3ccd041 - [LowerTypeTests] Emit cfi_jt aliases regardless of function export
Nick Desaulniers via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 27 11:45:44 PDT 2021
Author: Nick Desaulniers
Date: 2021-10-27T11:36:26-07:00
New Revision: 3ccd041af920125595a992becd0e1e4083ce562b
URL: https://github.com/llvm/llvm-project/commit/3ccd041af920125595a992becd0e1e4083ce562b
DIFF: https://github.com/llvm/llvm-project/commit/3ccd041af920125595a992becd0e1e4083ce562b.diff
LOG: [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
Added:
llvm/test/LTO/X86/cfi_jt_aliases.ll
Modified:
llvm/lib/Transforms/IPO/LowerTypeTests.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/IPO/LowerTypeTests.cpp b/llvm/lib/Transforms/IPO/LowerTypeTests.cpp
index 340baff90904f..26aa858cb8279 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 0000000000000..d5d85d0dcbd35
--- /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"
+
+ at 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 = !{}
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