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[CodeGen] -fsanitize=alignment: add cl::opt sanitize-alignment-builtin to disable memcpy instrumentation #69240

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merged 1 commit into from
Oct 18, 2023
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[CodeGen] -fsanitize=alignment: add cl::opt sanitize-alignment-builtin to disable memcpy instrumentation #69240

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7 changes: 6 additions & 1 deletion clang/lib/CodeGen/CGBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,11 @@ using namespace clang;
using namespace CodeGen;
using namespace llvm;

static llvm::cl::opt<bool> ClSanitizeAlignmentBuiltin(
"sanitize-alignment-builtin", llvm::cl::Hidden,
llvm::cl::desc("Instrument builtin functions for -fsanitize=alignment"),
llvm::cl::init(true));

Comment on lines +69 to +73
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Why are you using a cl::opt here rather than a proper CodeGenOption? We generally don't use cl::opt in clang and want our options to be provided via our option structs instead, so that clang can be used as a library.

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@MaskRay MaskRay Oct 19, 2023 •
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I acknowledge that cl::opt is discouraged (clang/lib has very few of them). This is a temporary workaround (so that our users can perform cleanups without being blocked) and should not be in Clang for too long. I'll revert this after ~two months, assuming that rolling update users (like us) have caught up on the change and tested their code bases. Given how large our code base is and how few (relatively) problems identified, I reasonably expect that the effect of instrumenting memcpy is small and we don't really need a driver option or cc1 option.

I modeled this after cl::opt<bool> ClSanitizeOnOptimizerEarlyEP in clang/lib/CodeGen/BackendUtil.cpp and thought that cl::opt might look more experimental than a cc1 option...

static void initializeAlloca(CodeGenFunction &CGF, AllocaInst *AI, Value *Size,
Align AlignmentInBytes) {
ConstantInt *Byte;
Expand Down Expand Up @@ -2788,7 +2793,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
EmitNonNullArgCheck(RValue::get(Val), Arg->getType(), Arg->getExprLoc(), FD,
ParmNum);

if (SanOpts.has(SanitizerKind::Alignment)) {
if (SanOpts.has(SanitizerKind::Alignment) && ClSanitizeAlignmentBuiltin) {
SanitizerSet SkippedChecks;
SkippedChecks.set(SanitizerKind::All);
SkippedChecks.clear(SanitizerKind::Alignment);
Expand Down
45 changes: 31 additions & 14 deletions clang/test/CodeGen/catch-undef-behavior.c
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@@ -1,6 +1,8 @@
// RUN: %clang_cc1 -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-UBSAN
// RUN: %clang_cc1 -fsanitize-trap=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-TRAP
// RUN: %clang_cc1 -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefixes=CHECK-COMMON,CHECK-UBSAN,CHECK-ALIGNMENT-BUILTIN
// RUN: %clang_cc1 -fsanitize-trap=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefixes=CHECK-COMMON,CHECK-ALIGNMENT-BUILTIN,CHECK-TRAP
// RUN: %clang_cc1 -fsanitize=signed-integer-overflow -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-OVERFLOW
/// A variant of CHECK-UBSAN with -sanitize-alignment-builtin disabled
// RUN: %clang_cc1 -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu -mllvm -sanitize-alignment-builtin=0 | FileCheck %s --check-prefixes=CHECK-COMMON,CHECK-UBSAN-NO-ALIGNMENT-BUILTIN

// CHECK-UBSAN: @[[INT:.*]] = private unnamed_addr constant { i16, i16, [6 x i8] } { i16 0, i16 11, [6 x i8] c"'int'\00" }

Expand Down Expand Up @@ -363,11 +365,13 @@ extern void *memcpy(void *, const void *, unsigned long) __attribute__((nonnull(
void call_memcpy_nonnull(void *p, void *q, int sz) {
// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
// CHECK-COMMON-NOT: call

// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
// CHECK-COMMON-NOT: call

Expand All @@ -379,18 +383,23 @@ void call_memcpy_nonnull(void *p, void *q, int sz) {
void call_memcpy(long *p, short *q, int sz) {
// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg(
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
// CHECK-COMMON: and i64 %[[#]], 7, !nosanitize
// CHECK-COMMON: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: and i64 %[[#]], 7, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-UBSAN: call void @__ubsan_handle_type_mismatch_v1(ptr @[[LINE_1600]]
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN-NOT: call void @__ubsan_handle_type_mismatch_v1(
// CHECK-TRAP: call void @llvm.ubsantrap(i8 22)

// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg(
// CHECK-UBSAN-DISABLE-BUILTIN: call
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
// CHECK-COMMON: and i64 %[[#]], 1, !nosanitize
// CHECK-COMMON: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: and i64 %[[#]], 1, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-UBSAN: call void @__ubsan_handle_type_mismatch_v1(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN-NOT: call
// CHECK-TRAP: call void @llvm.ubsantrap(i8 22)

// CHECK-COMMON: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %0, ptr align 2 %1, i64 %conv, i1 false)
Expand All @@ -405,14 +414,16 @@ void call_memcpy(long *p, short *q, int sz) {

// CHECK-COMMON-LABEL: define{{.*}} void @call_memcpy_inline(
void call_memcpy_inline(long *p, short *q) {
// CHECK-COMMON: and i64 %[[#]], 7, !nosanitize
// CHECK-COMMON: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: and i64 %[[#]], 7, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-UBSAN: call void @__ubsan_handle_type_mismatch_v1(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN-NOT: call
// CHECK-TRAP: call void @llvm.ubsantrap(i8 22)

// CHECK-COMMON: and i64 %[[#]], 1, !nosanitize
// CHECK-COMMON: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: and i64 %[[#]], 1, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-UBSAN: call void @__ubsan_handle_type_mismatch_v1(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN-NOT: call
// CHECK-TRAP: call void @llvm.ubsantrap(i8 22)

// CHECK-COMMON: call void @llvm.memcpy.inline.p0.p0.i64(ptr align 8 %0, ptr align 2 %1, i64 2, i1 false)
Expand All @@ -425,10 +436,12 @@ extern void *memmove(void *, const void *, unsigned long) __attribute__((nonnull
void call_memmove_nonnull(void *p, void *q, int sz) {
// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg(
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)

// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg(
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
memmove(p, q, sz);
}
Expand All @@ -437,18 +450,22 @@ void call_memmove_nonnull(void *p, void *q, int sz) {
void call_memmove(long *p, short *q, int sz) {
// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg(
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
// CHECK-COMMON: and i64 %[[#]], 7, !nosanitize
// CHECK-COMMON: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: and i64 %[[#]], 7, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-UBSAN: call void @__ubsan_handle_type_mismatch_v1(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN-NOT: call
// CHECK-TRAP: call void @llvm.ubsantrap(i8 22)

// CHECK-COMMON: icmp ne ptr {{.*}}, null
// CHECK-UBSAN: call void @__ubsan_handle_nonnull_arg(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN: call void @__ubsan_handle_nonnull_arg(
// CHECK-TRAP: call void @llvm.ubsantrap(i8 16)
// CHECK-COMMON: and i64 %[[#]], 1, !nosanitize
// CHECK-COMMON: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: and i64 %[[#]], 1, !nosanitize
// CHECK-ALIGNMENT-BUILTIN: icmp eq i64 %[[#]], 0, !nosanitize
// CHECK-UBSAN: call void @__ubsan_handle_type_mismatch_v1(
// CHECK-UBSAN-NO-ALIGNMENT-BUILTIN-NOT: call
// CHECK-TRAP: call void @llvm.ubsantrap(i8 22)

// CHECK-COMMON: call void @llvm.memmove.p0.p0.i64(ptr align 8 %0, ptr align 2 %1, i64 %conv, i1 false)
Expand Down