On Fri, Oct 13, 2017 at 1:42 PM Vedant Kumar <v...@apple.com> wrote: > On Oct 13, 2017, at 1:39 PM, Vedant Kumar <v...@apple.com> wrote: > > Hey Eric, > > I'm sorry for the breakage. I made sure to check the run-time tests in > compiler-rt but we could have missing coverage there. > > The original version of this patch restricted the prologue data changes to > Darwin only. We can switch back to that easily, just let me know. > > > Actually I'll go ahead and work a patch up. > > Appreciated :)
Basically we were getting an error of: error: Cannot represent a difference across sections trying to compile things with the current code. Thanks! -eric > vedant > > > vedant > > > On Oct 13, 2017, at 1:33 PM, Eric Christopher <echri...@gmail.com> wrote: > > Hi Vedant, > > So this actually broke -fsanitize=function on linux. Han is working up a > testcase for it, but letting you know for now that we'll probably need some > change here. > > -eric > > On Tue, Sep 12, 2017 at 5:05 PM Vedant Kumar via cfe-commits < > cfe-commits@lists.llvm.org> wrote: > >> Author: vedantk >> Date: Tue Sep 12 17:04:35 2017 >> New Revision: 313096 >> >> URL: http://llvm.org/viewvc/llvm-project?rev=313096&view=rev >> Log: >> [ubsan] Function Sanitizer: Don't require writable text segments >> >> This change will make it possible to use -fsanitize=function on Darwin and >> possibly on other platforms. It fixes an issue with the way RTTI is >> stored into >> function prologue data. >> >> On Darwin, addresses stored in prologue data can't require run-time >> fixups and >> must be PC-relative. Run-time fixups are undesirable because they >> necessitate >> writable text segments, which can lead to security issues. And absolute >> addresses are undesirable because they break PIE mode. >> >> The fix is to create a private global which points to the RTTI, and then >> to >> encode a PC-relative reference to the global into prologue data. >> >> Differential Revision: https://reviews.llvm.org/D37597 >> >> Modified: >> cfe/trunk/lib/CodeGen/CGExpr.cpp >> cfe/trunk/lib/CodeGen/CodeGenFunction.cpp >> cfe/trunk/lib/CodeGen/CodeGenFunction.h >> cfe/trunk/lib/CodeGen/TargetInfo.cpp >> cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp >> >> Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=313096&r1=313095&r2=313096&view=diff >> >> ============================================================================== >> --- cfe/trunk/lib/CodeGen/CGExpr.cpp (original) >> +++ cfe/trunk/lib/CodeGen/CGExpr.cpp Tue Sep 12 17:04:35 2017 >> @@ -4409,10 +4409,7 @@ RValue CodeGenFunction::EmitCall(QualTyp >> SanitizerScope SanScope(this); >> llvm::Constant *FTRTTIConst = >> CGM.GetAddrOfRTTIDescriptor(QualType(FnType, 0), >> /*ForEH=*/true); >> - llvm::Type *PrefixStructTyElems[] = { >> - PrefixSig->getType(), >> - FTRTTIConst->getType() >> - }; >> + llvm::Type *PrefixStructTyElems[] = {PrefixSig->getType(), >> Int32Ty}; >> llvm::StructType *PrefixStructTy = llvm::StructType::get( >> CGM.getLLVMContext(), PrefixStructTyElems, /*isPacked=*/true); >> >> @@ -4433,8 +4430,10 @@ RValue CodeGenFunction::EmitCall(QualTyp >> EmitBlock(TypeCheck); >> llvm::Value *CalleeRTTIPtr = >> Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, >> 0, 1); >> - llvm::Value *CalleeRTTI = >> + llvm::Value *CalleeRTTIEncoded = >> Builder.CreateAlignedLoad(CalleeRTTIPtr, getPointerAlign()); >> + llvm::Value *CalleeRTTI = >> + DecodeAddrUsedInPrologue(CalleePtr, CalleeRTTIEncoded); >> llvm::Value *CalleeRTTIMatch = >> Builder.CreateICmpEQ(CalleeRTTI, FTRTTIConst); >> llvm::Constant *StaticData[] = { >> >> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=313096&r1=313095&r2=313096&view=diff >> >> ============================================================================== >> --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original) >> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Tue Sep 12 17:04:35 2017 >> @@ -429,6 +429,43 @@ bool CodeGenFunction::ShouldXRayInstrume >> return CGM.getCodeGenOpts().XRayInstrumentFunctions; >> } >> >> +llvm::Constant * >> +CodeGenFunction::EncodeAddrForUseInPrologue(llvm::Function *F, >> + llvm::Constant *Addr) { >> + // Addresses stored in prologue data can't require run-time fixups and >> must >> + // be PC-relative. Run-time fixups are undesirable because they >> necessitate >> + // writable text segments, which are unsafe. And absolute addresses are >> + // undesirable because they break PIE mode. >> + >> + // Add a layer of indirection through a private global. Taking its >> address >> + // won't result in a run-time fixup, even if Addr has linkonce_odr >> linkage. >> + auto *GV = new llvm::GlobalVariable(CGM.getModule(), Addr->getType(), >> + /*isConstant=*/true, >> + llvm::GlobalValue::PrivateLinkage, >> Addr); >> + >> + // Create a PC-relative address. >> + auto *GOTAsInt = llvm::ConstantExpr::getPtrToInt(GV, IntPtrTy); >> + auto *FuncAsInt = llvm::ConstantExpr::getPtrToInt(F, IntPtrTy); >> + auto *PCRelAsInt = llvm::ConstantExpr::getSub(GOTAsInt, FuncAsInt); >> + return (IntPtrTy == Int32Ty) >> + ? PCRelAsInt >> + : llvm::ConstantExpr::getTrunc(PCRelAsInt, Int32Ty); >> +} >> + >> +llvm::Value * >> +CodeGenFunction::DecodeAddrUsedInPrologue(llvm::Value *F, >> + llvm::Value *EncodedAddr) { >> + // Reconstruct the address of the global. >> + auto *PCRelAsInt = Builder.CreateSExt(EncodedAddr, IntPtrTy); >> + auto *FuncAsInt = Builder.CreatePtrToInt(F, IntPtrTy, "func_addr.int >> "); >> + auto *GOTAsInt = Builder.CreateAdd(PCRelAsInt, FuncAsInt, " >> global_addr.int"); >> + auto *GOTAddr = Builder.CreateIntToPtr(GOTAsInt, Int8PtrPtrTy, >> "global_addr"); >> + >> + // Load the original pointer through the global. >> + return Builder.CreateLoad(Address(GOTAddr, getPointerAlign()), >> + "decoded_addr"); >> +} >> + >> /// EmitFunctionInstrumentation - Emit LLVM code to call the specified >> /// instrumentation function with the current function and the call >> site, if >> /// function instrumentation is enabled. >> @@ -856,7 +893,10 @@ void CodeGenFunction::StartFunction(Glob >> CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) >> { >> llvm::Constant *FTRTTIConst = >> CGM.GetAddrOfRTTIDescriptor(FD->getType(), /*ForEH=*/true); >> - llvm::Constant *PrologueStructElems[] = { PrologueSig, >> FTRTTIConst }; >> + llvm::Constant *FTRTTIConstEncoded = >> + EncodeAddrForUseInPrologue(Fn, FTRTTIConst); >> + llvm::Constant *PrologueStructElems[] = {PrologueSig, >> + FTRTTIConstEncoded}; >> llvm::Constant *PrologueStructConst = >> llvm::ConstantStruct::getAnon(PrologueStructElems, >> /*Packed=*/true); >> Fn->setPrologueData(PrologueStructConst); >> >> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=313096&r1=313095&r2=313096&view=diff >> >> ============================================================================== >> --- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original) >> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Tue Sep 12 17:04:35 2017 >> @@ -1776,6 +1776,15 @@ public: >> /// EmitMCountInstrumentation - Emit call to .mcount. >> void EmitMCountInstrumentation(); >> >> + /// Encode an address into a form suitable for use in a function >> prologue. >> + llvm::Constant *EncodeAddrForUseInPrologue(llvm::Function *F, >> + llvm::Constant *Addr); >> + >> + /// Decode an address used in a function prologue, encoded by \c >> + /// EncodeAddrForUseInPrologue. >> + llvm::Value *DecodeAddrUsedInPrologue(llvm::Value *F, >> + llvm::Value *EncodedAddr); >> + >> /// EmitFunctionProlog - Emit the target specific LLVM code to load the >> /// arguments for the given function. This is also responsible for >> naming the >> /// LLVM function arguments. >> >> Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=313096&r1=313095&r2=313096&view=diff >> >> ============================================================================== >> --- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original) >> +++ cfe/trunk/lib/CodeGen/TargetInfo.cpp Tue Sep 12 17:04:35 2017 >> @@ -1086,8 +1086,8 @@ public: >> getUBSanFunctionSignature(CodeGen::CodeGenModule &CGM) const override { >> unsigned Sig = (0xeb << 0) | // jmp rel8 >> (0x06 << 8) | // .+0x08 >> - ('F' << 16) | >> - ('T' << 24); >> + ('v' << 16) | >> + ('2' << 24); >> return llvm::ConstantInt::get(CGM.Int32Ty, Sig); >> } >> >> @@ -2277,17 +2277,10 @@ public: >> >> llvm::Constant * >> getUBSanFunctionSignature(CodeGen::CodeGenModule &CGM) const override { >> - unsigned Sig; >> - if (getABIInfo().has64BitPointers()) >> - Sig = (0xeb << 0) | // jmp rel8 >> - (0x0a << 8) | // .+0x0c >> - ('F' << 16) | >> - ('T' << 24); >> - else >> - Sig = (0xeb << 0) | // jmp rel8 >> - (0x06 << 8) | // .+0x08 >> - ('F' << 16) | >> - ('T' << 24); >> + unsigned Sig = (0xeb << 0) | // jmp rel8 >> + (0x06 << 8) | // .+0x08 >> + ('v' << 16) | >> + ('2' << 24); >> return llvm::ConstantInt::get(CGM.Int32Ty, Sig); >> } >> >> >> Modified: cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp?rev=313096&r1=313095&r2=313096&view=diff >> >> ============================================================================== >> --- cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp (original) >> +++ cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp Tue Sep 12 >> 17:04:35 2017 >> @@ -16,6 +16,10 @@ struct S { >> // Check that type mismatch handler is not modified by ASan. >> // CHECK-ASAN: private unnamed_addr global { { [{{.*}} x i8]*, i32, i32 >> }, { i16, i16, [4 x i8] }*, i8*, i8 } { {{.*}}, { i16, i16, [4 x i8] }* >> [[TYPE_DESCR]], {{.*}} } >> >> +// CHECK: [[IndirectRTTI_ZTIFvPFviEE:@.+]] = private constant i8* >> bitcast ({ i8*, i8* }* @_ZTIFvPFviEE to i8*) >> +// CHECK-X86: [[IndirectRTTI_ZTIFvPFviEE:@.+]] = private constant i8* >> bitcast ({ i8*, i8* }* @_ZTIFvPFviEE to i8*) >> +// CHECK-X32: [[IndirectRTTI_ZTIFvPFviEE:@.+]] = private constant i8* >> bitcast ({ i8*, i8* }* @_ZTIFvPFviEE to i8*) >> + >> struct T : S {}; >> >> // CHECK-LABEL: @_Z17reference_binding >> @@ -395,23 +399,30 @@ void downcast_reference(B &b) { >> // CHECK-NEXT: br i1 [[AND]] >> } >> >> -// CHECK-LABEL: @_Z22indirect_function_callPFviE({{.*}} prologue <{ i32, >> i8* }> <{ i32 1413876459, i8* bitcast ({ i8*, i8* }* @_ZTIFvPFviEE to i8*) >> }> >> -// CHECK-X32: @_Z22indirect_function_callPFviE({{.*}} prologue <{ i32, >> i8* }> <{ i32 1413875435, i8* bitcast ({ i8*, i8* }* @_ZTIFvPFviEE to i8*) >> }> >> -// CHECK-X86: @_Z22indirect_function_callPFviE({{.*}} prologue <{ i32, >> i8* }> <{ i32 1413875435, i8* bitcast ({ i8*, i8* }* @_ZTIFvPFviEE to i8*) >> }> >> +// >> +// CHECK-LABEL: @_Z22indirect_function_callPFviE({{.*}} prologue <{ i32, >> i32 }> <{ i32 846595819, i32 trunc (i64 sub (i64 ptrtoint (i8** {{.*}} to >> i64), i64 ptrtoint (void (void (i32)*)* @_Z22indirect_function_callPFviE to >> i64)) to i32) }> >> +// CHECK-X32: @_Z22indirect_function_callPFviE({{.*}} prologue <{ i32, >> i32 }> <{ i32 846595819, i32 sub (i32 ptrtoint (i8** >> [[IndirectRTTI_ZTIFvPFviEE]] to i32), i32 ptrtoint (void (void (i32)*)* >> @_Z22indirect_function_callPFviE to i32)) }> >> +// CHECK-X86: @_Z22indirect_function_callPFviE({{.*}} prologue <{ i32, >> i32 }> <{ i32 846595819, i32 sub (i32 ptrtoint (i8** >> [[IndirectRTTI_ZTIFvPFviEE]] to i32), i32 ptrtoint (void (void (i32)*)* >> @_Z22indirect_function_callPFviE to i32)) }> >> void indirect_function_call(void (*p)(int)) { >> - // CHECK: [[PTR:%.+]] = bitcast void (i32)* {{.*}} to <{ i32, i8* }>* >> + // CHECK: [[PTR:%.+]] = bitcast void (i32)* {{.*}} to <{ i32, i32 }>* >> >> // Signature check >> - // CHECK-NEXT: [[SIGPTR:%.+]] = getelementptr <{ i32, i8* }>, <{ i32, >> i8* }>* [[PTR]], i32 0, i32 0 >> + // CHECK-NEXT: [[SIGPTR:%.+]] = getelementptr <{ i32, i32 }>, <{ i32, >> i32 }>* [[PTR]], i32 0, i32 0 >> // CHECK-NEXT: [[SIG:%.+]] = load i32, i32* [[SIGPTR]] >> - // CHECK-NEXT: [[SIGCMP:%.+]] = icmp eq i32 [[SIG]], 1413876459 >> + // CHECK-NEXT: [[SIGCMP:%.+]] = icmp eq i32 [[SIG]], 846595819 >> // CHECK-NEXT: br i1 [[SIGCMP]] >> >> // RTTI pointer check >> - // CHECK: [[RTTIPTR:%.+]] = getelementptr <{ i32, i8* }>, <{ i32, i8* >> }>* [[PTR]], i32 0, i32 1 >> - // CHECK-NEXT: [[RTTI:%.+]] = load i8*, i8** [[RTTIPTR]] >> + // CHECK: [[RTTIPTR:%.+]] = getelementptr <{ i32, i32 }>, <{ i32, i32 >> }>* [[PTR]], i32 0, i32 1 >> + // CHECK-NEXT: [[RTTIEncIntTrunc:%.+]] = load i32, i32* [[RTTIPTR]] >> + // CHECK-NEXT: [[RTTIEncInt:%.+]] = sext i32 [[RTTIEncIntTrunc]] to i64 >> + // CHECK-NEXT: [[FuncAddrInt:%.+]] = ptrtoint void (i32)* {{.*}} to i64 >> + // CHECK-NEXT: [[IndirectGVInt:%.+]] = add i64 [[RTTIEncInt]], >> [[FuncAddrInt]] >> + // CHECK-NEXT: [[IndirectGV:%.+]] = inttoptr i64 [[IndirectGVInt]] to >> i8** >> + // CHECK-NEXT: [[RTTI:%.+]] = load i8*, i8** [[IndirectGV]], align 8 >> // CHECK-NEXT: [[RTTICMP:%.+]] = icmp eq i8* [[RTTI]], bitcast ({ i8*, >> i8* }* @_ZTIFviE to i8*) >> // CHECK-NEXT: br i1 [[RTTICMP]] >> + >> p(42); >> } >> >> >> >> _______________________________________________ >> cfe-commits mailing list >> cfe-commits@lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >> > > >
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