forked from OSchip/llvm-project
[sanitizer-coverage] Change cmp instrumentation to distinguish const operands
This implementation of SanitizerCoverage instrumentation inserts different
callbacks depending on constantness of operands:
1. If both operands are non-const, then a usual
__sanitizer_cov_trace_cmp[1248] call is inserted.
2. If exactly one operand is const, then a
__sanitizer_cov_trace_const_cmp[1248] call is inserted. The first
argument of the call is always the constant one.
3. If both operands are const, then no callback is inserted.
This separation comes useful in fuzzing when tasks like "find one operand
of the comparison in input arguments and replace it with the other one"
have to be done. The new instrumentation allows us to not waste time on
searching the constant operands in the input.
Patch by Victor Chibotaru.
llvm-svn: 310600
This commit is contained in:
Alexander Potapenko
parent
c3bcdc2f1a
commit
5241081532
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@ -211,6 +211,14 @@ the `LLVM GEP instructions <http://llvm.org/docs/GetElementPtr.html>`_
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void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2);
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void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2);
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// Called before a comparison instruction if exactly one of the arguments is constant.
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// Arg1 and Arg2 are arguments of the comparison, Arg1 is a compile-time constant.
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// These callbacks are emitted by -fsanitize-coverage=trace-cmp since 2017-08-11
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void __sanitizer_cov_trace_const_cmp1(uint8_t Arg1, uint8_t Arg2);
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void __sanitizer_cov_trace_const_cmp2(uint16_t Arg1, uint16_t Arg2);
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void __sanitizer_cov_trace_const_cmp4(uint32_t Arg1, uint32_t Arg2);
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void __sanitizer_cov_trace_const_cmp8(uint64_t Arg1, uint64_t Arg2);
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// Called before a switch statement.
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// Val is the switch operand.
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// Cases[0] is the number of case constants.
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@ -227,7 +235,6 @@ the `LLVM GEP instructions <http://llvm.org/docs/GetElementPtr.html>`_
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// for every non-constant array index.
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void __sanitizer_cov_trace_gep(uintptr_t Idx);
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This interface is a subject to change.
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Default implementation
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@ -46,6 +46,14 @@ static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1";
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static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2";
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static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4";
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static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8";
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static const char *const SanCovTraceConstCmp1 =
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"__sanitizer_cov_trace_const_cmp1";
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static const char *const SanCovTraceConstCmp2 =
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"__sanitizer_cov_trace_const_cmp2";
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static const char *const SanCovTraceConstCmp4 =
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"__sanitizer_cov_trace_const_cmp4";
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static const char *const SanCovTraceConstCmp8 =
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"__sanitizer_cov_trace_const_cmp8";
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static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4";
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static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8";
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static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep";
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@ -204,12 +212,13 @@ private:
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Function *SanCovTracePCIndir;
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Function *SanCovTracePC, *SanCovTracePCGuard;
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Function *SanCovTraceCmpFunction[4];
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Function *SanCovTraceConstCmpFunction[4];
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Function *SanCovTraceDivFunction[2];
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Function *SanCovTraceGepFunction;
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Function *SanCovTraceSwitchFunction;
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InlineAsm *EmptyAsm;
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Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy,
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*Int8Ty, *Int8PtrTy;
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*Int16Ty, *Int8Ty, *Int8PtrTy;
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Module *CurModule;
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Triple TargetTriple;
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LLVMContext *C;
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@ -281,6 +290,7 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
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Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
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Int64Ty = IRB.getInt64Ty();
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Int32Ty = IRB.getInt32Ty();
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Int16Ty = IRB.getInt16Ty();
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Int8Ty = IRB.getInt8Ty();
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SanCovTracePCIndir = checkSanitizerInterfaceFunction(
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@ -298,6 +308,19 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty));
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SanCovTraceConstCmpFunction[0] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceConstCmp1, VoidTy, Int8Ty, Int8Ty));
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SanCovTraceConstCmpFunction[1] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceConstCmp2, VoidTy, Int16Ty, Int16Ty));
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SanCovTraceConstCmpFunction[2] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceConstCmp4, VoidTy, Int32Ty, Int32Ty));
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SanCovTraceConstCmpFunction[3] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty));
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SanCovTraceDivFunction[0] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceDiv4, VoidTy, IRB.getInt32Ty()));
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@ -316,6 +339,8 @@ bool SanitizerCoverageModule::runOnModule(Module &M) {
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for (int i = 0; i < 3; i++) {
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SanCovTraceCmpFunction[i]->addParamAttr(0, Attribute::ZExt);
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SanCovTraceCmpFunction[i]->addParamAttr(1, Attribute::ZExt);
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SanCovTraceConstCmpFunction[i]->addParamAttr(0, Attribute::ZExt);
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SanCovTraceConstCmpFunction[i]->addParamAttr(1, Attribute::ZExt);
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}
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SanCovTraceDivFunction[0]->addParamAttr(0, Attribute::ZExt);
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}
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@ -644,10 +669,21 @@ void SanitizerCoverageModule::InjectTraceForCmp(
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TypeSize == 64 ? 3 : -1;
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if (CallbackIdx < 0) continue;
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// __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
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auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
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bool FirstIsConst = isa<ConstantInt>(A0);
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bool SecondIsConst = isa<ConstantInt>(A1);
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// If both are const, then we don't need such a comparison.
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if (FirstIsConst && SecondIsConst) continue;
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// If only one is const, then make it the first callback argument.
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if (FirstIsConst || SecondIsConst) {
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CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
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if (SecondIsConst)
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std::swap(A0, A1);
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}
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auto Ty = Type::getIntNTy(*C, TypeSize);
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IRB.CreateCall(
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SanCovTraceCmpFunction[CallbackIdx],
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{IRB.CreateIntCast(A0, Ty, true), IRB.CreateIntCast(A1, Ty, true)});
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IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
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IRB.CreateIntCast(A1, Ty, true)});
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}
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}
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}
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@ -0,0 +1,64 @@
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; Test -sanitizer-coverage-trace-compares=1
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; RUN: opt < %s -sancov -sanitizer-coverage-level=1 -sanitizer-coverage-trace-compares=1 -S | FileCheck %s
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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"
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target triple = "x86_64-unknown-linux-gnu"
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define i32 @foo(i32 %a, i32 %b) #0 {
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entry:
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; compare (non-const, non-const)
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%cmp = icmp slt i32 %a, %b
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; CHECK: call void @__sanitizer_cov_trace_cmp4
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; CHECK-NEXT: icmp slt i32 %a, %b
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; compare (const, non-const)
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icmp slt i32 %a, 1
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; CHECK: call void @__sanitizer_cov_trace_const_cmp4(i32 1, i32 %a)
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; CHECK-NEXT: icmp slt i32 %a, 1
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; compare (non-const, const)
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icmp slt i32 1, %a
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; CHECK: call void @__sanitizer_cov_trace_const_cmp4(i32 1, i32 %a)
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; CHECK-NEXT: icmp slt i32 1, %a
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; compare (const, const) - should not be instrumented
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icmp slt i32 1, 0
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; CHECK-NOT: call void @__sanitizer_cov_trace
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; CHECK icmp slt i32 1, 0
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; compare variables of byte size
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%x = trunc i32 %a to i8
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icmp slt i8 %x, 1
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; CHECK: call void @__sanitizer_cov_trace_const_cmp1(i8 1, i8 %x)
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; CHECK-NEXT: icmp slt i8 %x, 1
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icmp slt i8 1, %x
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; CHECK: call void @__sanitizer_cov_trace_const_cmp1(i8 1, i8 %x)
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; CHECK-NEXT: icmp slt i8 1, %x
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; compare variables of word size
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%y = trunc i32 %a to i16
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icmp slt i16 %y, 1
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; CHECK: call void @__sanitizer_cov_trace_const_cmp2(i16 1, i16 %y)
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; CHECK-NEXT: icmp slt i16 %y, 1
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icmp slt i16 1, %y
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; CHECK: call void @__sanitizer_cov_trace_const_cmp2(i16 1, i16 %y)
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; CHECK-NEXT: icmp slt i16 1, %y
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; compare variables of qword size
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%z = zext i32 %a to i64
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icmp slt i64 %z, 1
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; CHECK: call void @__sanitizer_cov_trace_const_cmp8(i64 1, i64 %z)
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; CHECK-NEXT: icmp slt i64 %z, 1
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icmp slt i64 1, %z
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; CHECK: call void @__sanitizer_cov_trace_const_cmp8(i64 1, i64 %z)
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; CHECK-NEXT: icmp slt i64 1, %z
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%conv = zext i1 %cmp to i32
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ret i32 %conv
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}
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