; Test for the conservative assembly handling mode used by KMSAN. ; RUN: opt < %s -msan-kernel=1 -msan-check-access-address=0 \ ; RUN: -msan-handle-asm-conservative=0 -S -passes=msan 2>&1 | FileCheck \ ; RUN: "-check-prefix=CHECK" %s ; RUN: opt < %s -msan -msan-kernel=1 -msan-check-access-address=0 -msan-handle-asm-conservative=0 -S | FileCheck -check-prefixes=CHECK %s ; RUN: opt < %s -msan-kernel=1 -msan-check-access-address=0 \ ; RUN: -msan-handle-asm-conservative=1 -S -passes=msan 2>&1 | FileCheck \ ; RUN: "-check-prefixes=CHECK,CHECK-CONS" %s ; RUN: opt < %s -msan -msan-kernel=1 -msan-check-access-address=0 -msan-handle-asm-conservative=1 -S | FileCheck -check-prefixes=CHECK,CHECK-CONS %s target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" ; The IR below was generated from the following source: ; int main() { ; bool bit; ; unsigned long value = 2; ; long nr = 0; ; unsigned long *addr = &value; ; asm("btsq %2, %1; setc %0" : "=qm" (bit), "=m" (addr): "Ir" (nr)); ; if (bit) ; return 0; ; else ; return 1; ; } ; ; In the regular instrumentation mode MSan is unable to understand that |bit| ; is initialized by the asm() call, and therefore reports a false positive on ; the if-statement. ; The conservative assembly handling mode initializes every memory location ; passed by pointer into an asm() call. This prevents false positive reports, ; but may introduce false negatives. ; ; This test makes sure that the conservative mode unpoisons the shadow of |bit| ; by writing 0 to it. define dso_local i32 @main() sanitize_memory { entry: %retval = alloca i32, align 4 %bit = alloca i8, align 1 %value = alloca i64, align 8 %nr = alloca i64, align 8 %addr = alloca i64*, align 8 store i32 0, i32* %retval, align 4 store i64 2, i64* %value, align 8 store i64 0, i64* %nr, align 8 store i64* %value, i64** %addr, align 8 %0 = load i64, i64* %nr, align 8 call void asm "btsq $2, $1; setc $0", "=*qm,=*m,Ir,~{dirflag},~{fpsr},~{flags}"(i8* %bit, i64** %addr, i64 %0) %1 = load i8, i8* %bit, align 1 %tobool = trunc i8 %1 to i1 br i1 %tobool, label %if.then, label %if.else if.then: ; preds = %entry ret i32 0 if.else: ; preds = %entry ret i32 1 } ; %nr is first poisoned, then unpoisoned (written to). Need to optimize this in the future. ; CHECK: [[NRC1:%.*]] = bitcast i64* %nr to i8* ; CHECK: call void @__msan_poison_alloca(i8* [[NRC1]]{{.*}}) ; CHECK: [[NRC2:%.*]] = bitcast i64* %nr to i8* ; CHECK: call { i8*, i32* } @__msan_metadata_ptr_for_store_8(i8* [[NRC2]]) ; Hooks for inputs usually go before the assembly statement. But here we have none, ; because %nr is passed by value. However we check %nr for being initialized. ; CHECK-CONS: [[NRC3:%.*]] = bitcast i64* %nr to i8* ; CHECK-CONS: call { i8*, i32* } @__msan_metadata_ptr_for_load_8(i8* [[NRC3]]) ; In the conservative mode, call the store hooks for %bit and %addr: ; CHECK-CONS: call void @__msan_instrument_asm_store(i8* %bit, i64 1) ; CHECK-CONS: [[ADDR8S:%.*]] = bitcast i64** %addr to i8* ; CHECK-CONS: call void @__msan_instrument_asm_store(i8* [[ADDR8S]], i64 8) ; Landing pad for the %nr check above. ; CHECK-CONS: call void @__msan_warning ; CHECK: call void asm "btsq $2, $1; setc $0" ; Calculating the shadow offset of %bit. ; CHECKz: [[PTR:%.*]] = ptrtoint {{.*}} %bit to i64 ; CHECKz: [[SH_NUM:%.*]] = xor i64 [[PTR]] ; CHECKz: [[SHADOW:%.*]] = inttoptr i64 [[SH_NUM]] {{.*}} ; CHECK: [[META:%.*]] = call {{.*}} @__msan_metadata_ptr_for_load_1(i8* %bit) ; CHECK: [[SHADOW:%.*]] = extractvalue { i8*, i32* } [[META]], 0 ; Now load the shadow value for the boolean. ; CHECK: [[MSLD:%.*]] = load {{.*}} [[SHADOW]] ; CHECK: [[MSPROP:%.*]] = trunc i8 [[MSLD]] to i1 ; Is the shadow poisoned? ; CHECK: br i1 [[MSPROP]], label %[[IFTRUE:.*]], label {{.*}} ; If yes, raise a warning. ; CHECK: [[IFTRUE]]: ; CHECK: call void @__msan_warning