diff options
3 files changed, 87 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp index ec72e834059..15eba9089cb 100644 --- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp +++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp @@ -1132,6 +1132,10 @@ static GlobalVariable *createPrivateGlobalForSourceLoc(Module &M, /// Check if \p G has been created by a trusted compiler pass. static bool GlobalWasGeneratedByCompiler(GlobalVariable *G) { + // Do not instrument @llvm.global_ctors, @llvm.used, etc. + if (G->getName().startswith("llvm.")) + return true; + // Do not instrument asan globals. if (G->getName().startswith(kAsanGenPrefix) || G->getName().startswith(kSanCovGenPrefix) || @@ -1653,14 +1657,6 @@ bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) { if (!Ty->isSized()) return false; if (!G->hasInitializer()) return false; if (GlobalWasGeneratedByCompiler(G)) return false; // Our own globals. - // Touch only those globals that will not be defined in other modules. - // Don't handle ODR linkage types and COMDATs since other modules may be built - // without ASan. - if (G->getLinkage() != GlobalVariable::ExternalLinkage && - G->getLinkage() != GlobalVariable::PrivateLinkage && - G->getLinkage() != GlobalVariable::InternalLinkage) - return false; - if (G->hasComdat()) return false; // Two problems with thread-locals: // - The address of the main thread's copy can't be computed at link-time. // - Need to poison all copies, not just the main thread's one. @@ -1668,6 +1664,33 @@ bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) { // For now, just ignore this Global if the alignment is large. if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false; + // For non-COFF targets, only instrument globals known to be defined by this + // TU. + // FIXME: We can instrument comdat globals on ELF if we are using the + // GC-friendly metadata scheme. + if (!TargetTriple.isOSBinFormatCOFF()) { + if (!G->hasExactDefinition() || G->hasComdat()) + return false; + } else { + // On COFF, don't instrument non-ODR linkages. + if (G->isInterposable()) + return false; + } + + // If a comdat is present, it must have a selection kind that implies ODR + // semantics: no duplicates, any, or exact match. + if (Comdat *C = G->getComdat()) { + switch (C->getSelectionKind()) { + case Comdat::Any: + case Comdat::ExactMatch: + case Comdat::NoDuplicates: + break; + case Comdat::Largest: + case Comdat::SameSize: + return false; + } + } + if (G->hasSection()) { StringRef Section = G->getSection(); @@ -2121,6 +2144,7 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool new GlobalVariable(M, NewTy, G->isConstant(), Linkage, NewInitializer, "", G, G->getThreadLocalMode()); NewGlobal->copyAttributesFrom(G); + NewGlobal->setComdat(G->getComdat()); NewGlobal->setAlignment(MinRZ); // Move null-terminated C strings to "__asan_cstring" section on Darwin. diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_external_comdat.ll b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_external_comdat.ll new file mode 100644 index 00000000000..86a612d9843 --- /dev/null +++ b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_external_comdat.ll @@ -0,0 +1,9 @@ +; RUN: opt < %s -mtriple=x86_64-linux -asan -asan-module -asan-globals-live-support=0 -S | FileCheck %s + +$my_var = comdat any + +@my_var = global i32 42, align 4, comdat +; CHECK: @my_var = global i32 42, align 4, comdat + +; Don't instrument my_var, it is comdat. +; CHECK-NOT: __asan_register_globals diff --git a/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll b/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll new file mode 100644 index 00000000000..4fef094832a --- /dev/null +++ b/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll @@ -0,0 +1,46 @@ +; RUN: opt < %s -asan -asan-module -S | FileCheck %s + +; Generated like so: +; $ clang -S -emit-llvm -Xclang -disable-llvm-passes -fsanitize=address -O1 t.cpp -o t.ll +; const char *getstr() { return "asdf"; } + +; CHECK: $"??_C@_04JIHMPGLA@asdf?$AA@" = comdat any + +; CHECK: @"??_C@_04JIHMPGLA@asdf?$AA@" = +; CHECK-SAME: linkonce_odr dso_local unnamed_addr constant { [5 x i8], [59 x i8] } +; CHECK-SAME: { [5 x i8] c"asdf\00", [59 x i8] zeroinitializer }, comdat, align 32 + +; CHECK: @"__asan_global_??_C@_04JIHMPGLA@asdf?$AA@" = +; CHECK-SAME: private global { i64, i64, i64, i64, i64, i64, i64, i64 } +; CHECK-SAME: { i64 ptrtoint ({ [5 x i8], [59 x i8] }* @"??_C@_04JIHMPGLA@asdf?$AA@" to i64), +; CHECK-SAME: i64 5, i64 64, i64 ptrtoint ([17 x i8]* @___asan_gen_.1 to i64), +; CHECK-SAME: i64 ptrtoint ([8 x i8]* @___asan_gen_ to i64), i64 0, +; CHECK-SAME: i64 ptrtoint ({ [6 x i8]*, i32, i32 }* @___asan_gen_.3 to i64), i64 0 }, +; CHECK-SAME: section ".ASAN$GL", comdat($"??_C@_04JIHMPGLA@asdf?$AA@"), align 64 + +; ModuleID = 't.cpp' +source_filename = "t.cpp" +target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-pc-windows-msvc19.13.26131" + +$"??_C@_04JIHMPGLA@asdf?$AA@" = comdat any + +@"??_C@_04JIHMPGLA@asdf?$AA@" = linkonce_odr dso_local unnamed_addr constant [5 x i8] c"asdf\00", comdat, align 1 + +; Function Attrs: nounwind sanitize_address uwtable +define dso_local i8* @"?getstr@@YAPEBDXZ"() #0 { +entry: + ret i8* getelementptr inbounds ([5 x i8], [5 x i8]* @"??_C@_04JIHMPGLA@asdf?$AA@", i32 0, i32 0) +} + +attributes #0 = { nounwind sanitize_address uwtable } + +!llvm.asan.globals = !{!0} +!llvm.module.flags = !{!2, !3} +!llvm.ident = !{!4} + +!0 = !{[5 x i8]* @"??_C@_04JIHMPGLA@asdf?$AA@", !1, !"<string literal>", i1 false, i1 false} +!1 = !{!"t.cpp", i32 1, i32 31} +!2 = !{i32 1, !"wchar_size", i32 2} +!3 = !{i32 7, !"PIC Level", i32 2} +!4 = !{!"clang version 7.0.0 "} |
