[asan] add option -asan-keep-uninstrumented-functions
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184927 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 22851b4..67a8325 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -44,6 +44,7 @@
#include "llvm/Support/system_error.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/BlackList.h"
+#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
@@ -131,6 +132,19 @@
cl::desc("File containing the list of objects to ignore "
"during instrumentation"), cl::Hidden);
+// This is an experimental feature that will allow to choose between
+// instrumented and non-instrumented code at link-time.
+// If this option is on, just before instrumenting a function we create its
+// clone; if the function is not changed by asan the clone is deleted.
+// If we end up with a clone, we put the instrumented function into a section
+// called "ASAN" and the uninstrumented function into a section called "NOASAN".
+//
+// This is still a prototype, we need to figure out a way to keep two copies of
+// a function so that the linker can easily choose one of them.
+static cl::opt<bool> ClKeepUninstrumented("asan-keep-uninstrumented-functions",
+ cl::desc("Keep uninstrumented copies of functions"),
+ cl::Hidden, cl::init(false));
+
// These flags allow to change the shadow mapping.
// The shadow mapping looks like
// Shadow = (Mem >> scale) + (1 << offset_log)
@@ -1106,8 +1120,7 @@
// If needed, insert __asan_init before checking for SanitizeAddress attr.
maybeInsertAsanInitAtFunctionEntry(F);
- if (!F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
- Attribute::SanitizeAddress))
+ if (!F.hasFnAttribute(Attribute::SanitizeAddress))
return false;
if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
@@ -1118,6 +1131,7 @@
SmallSet<Value*, 16> TempsToInstrument;
SmallVector<Instruction*, 16> ToInstrument;
SmallVector<Instruction*, 8> NoReturnCalls;
+ int NumAllocas = 0;
bool IsWrite;
// Fill the set of memory operations to instrument.
@@ -1136,6 +1150,8 @@
} else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
// ok, take it.
} else {
+ if (isa<AllocaInst>(BI))
+ NumAllocas++;
CallSite CS(BI);
if (CS) {
// A call inside BB.
@@ -1152,6 +1168,17 @@
}
}
+ Function *UninstrumentedDuplicate = 0;
+ bool LikelyToInstrument =
+ !NoReturnCalls.empty() || !ToInstrument.empty() || (NumAllocas > 0);
+ if (ClKeepUninstrumented && LikelyToInstrument) {
+ ValueToValueMapTy VMap;
+ UninstrumentedDuplicate = CloneFunction(&F, VMap, false);
+ UninstrumentedDuplicate->removeFnAttr(Attribute::SanitizeAddress);
+ UninstrumentedDuplicate->setName("NOASAN_" + F.getName());
+ F.getParent()->getFunctionList().push_back(UninstrumentedDuplicate);
+ }
+
// Instrument.
int NumInstrumented = 0;
for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
@@ -1176,9 +1203,25 @@
IRBuilder<> IRB(CI);
IRB.CreateCall(AsanHandleNoReturnFunc);
}
- DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
- return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
+ bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
+ DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
+
+ if (ClKeepUninstrumented) {
+ if (!res) {
+ // No instrumentation is done, no need for the duplicate.
+ if (UninstrumentedDuplicate)
+ UninstrumentedDuplicate->eraseFromParent();
+ } else {
+ // The function was instrumented. We must have the duplicate.
+ assert(UninstrumentedDuplicate);
+ UninstrumentedDuplicate->setSection("NOASAN");
+ assert(!F.hasSection());
+ F.setSection("ASAN");
+ }
+ }
+
+ return res;
}
static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {