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[msan] Implement -msan-disable-checks. 

To ease the deployment of KMSAN, we need a way to apply
__attribute__((no_sanitize("kernel-memory"))) to the whole source file.

Passing -msan-disable-checks=1 to the compiler will make it
treat every function in the file as if it was lacking the
sanitize_memory attribute.

Differential Revision: https://reviews.llvm.org/D115236
This commit is contained in:
Alexander Potapenko 2021-12-07 13:20:12 +01:00
parent 37a395b396
commit 1aa59ff2f7
2 changed files with 56 additions and 1 deletions
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8
llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
View File

@ -307,6 +307,11 @@ static cl::opt<bool>
cl::desc("Enable KernelMemorySanitizer instrumentation"),
cl::Hidden, cl::init(false));
static cl::opt<bool>
ClDisableChecks("msan-disable-checks",
cl::desc("Apply no_sanitize to the whole file"), cl::Hidden,
cl::init(false));
// This is an experiment to enable handling of cases where shadow is a non-zero
// compile-time constant. For some unexplainable reason they were silently
// ignored in the instrumentation.
@ -1095,7 +1100,8 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
MemorySanitizerVisitor(Function &F, MemorySanitizer &MS,
const TargetLibraryInfo &TLI)
: F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)), TLI(&TLI) {
bool SanitizeFunction = F.hasFnAttribute(Attribute::SanitizeMemory);
bool SanitizeFunction =
F.hasFnAttribute(Attribute::SanitizeMemory) && !ClDisableChecks;
InsertChecks = SanitizeFunction;
PropagateShadow = SanitizeFunction;
PoisonStack = SanitizeFunction && ClPoisonStack;

49
llvm/test/Instrumentation/MemorySanitizer/msan-disable-checks.ll Normal file
View File

@ -0,0 +1,49 @@
; Test for -msan-disable-checks, which should treat every function in the file
; as if it didn't have the sanitize_memory attribute.
; RUN: opt < %s -msan-check-access-address=0 -S -passes='module(msan-module),function(msan)' 2>&1 | FileCheck -allow-deprecated-dag-overlap -check-prefixes=CHECK,INSTR %s
; RUN: opt < %s -msan-check-access-address=0 -S -passes='module(msan-module),function(msan)' -msan-disable-checks=1 2>&1 | FileCheck -allow-deprecated-dag-overlap -check-prefixes=CHECK,NOSANITIZE %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
declare void @bar()
define i32 @SanitizeFn(i32 %x) uwtable sanitize_memory {
entry:
%tobool = icmp eq i32 %x, 0
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call void @bar()
br label %if.end
if.end: ; preds = %entry, %if.then
ret i32 %x
}
; CHECK-LABEL: @SanitizeFn
; INSTR: @__msan_warning
; NOSANITIZE-NOT: @__msan_warning
; NOSANITIZE: store i32 0, {{.*}} @__msan_retval_tls
; CHECK: ret i32
define i32 @NoSanitizeFn(i32 %x) uwtable {
entry:
%tobool = icmp eq i32 %x, 0
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call void @bar()
br label %if.end
if.end: ; preds = %entry, %if.then
ret i32 %x
}
; CHECK-LABEL: @NoSanitizeFn
; CHECK-NOT: @__msan_warning
; CHECK: store i32 0, {{.*}} @__msan_retval_tls
; CHECK: ret i32