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authorKostya Serebryany <kcc@google.com>2017-12-09 19:18:10 +0000
committerKostya Serebryany <kcc@google.com>2017-12-09 19:18:10 +0000
commitad3dbbda589b45eb4a70561209b46694e35ea46c (patch)
tree5e9661b30228f17609b2c2c900a0f7b4d973be28 /lib
parent9595ecdaa969da106b922e08dc9d21a92ee1a438 (diff)
[libFuzzer] even less aggressive step function for stack depth. Also don't use asan in one test to speed it up
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@320259 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r--lib/fuzzer/FuzzerTracePC.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/lib/fuzzer/FuzzerTracePC.h b/lib/fuzzer/FuzzerTracePC.h
index bc7e5ec03..300e5db38 100644
--- a/lib/fuzzer/FuzzerTracePC.h
+++ b/lib/fuzzer/FuzzerTracePC.h
@@ -274,8 +274,19 @@ void TracePC::CollectFeatures(Callback HandleFeature) const {
FirstFeature += ValueProfileMap.SizeInBits();
}
+ // Step function, grows similar to 8 * Log_2(A).
+ auto StackDepthStepFunction = [](uint32_t A) -> uint32_t {
+ uint32_t Log2 = 32 - __builtin_clz(A) - 1;
+ if (Log2 < 3) return A;
+ Log2 -= 3;
+ return (Log2 + 1) * 8 + ((A >> Log2) & 7);
+ };
+ assert(StackDepthStepFunction(1024) == 64);
+ assert(StackDepthStepFunction(1024 * 4) == 80);
+ assert(StackDepthStepFunction(1024 * 1024) == 144);
+
if (auto MaxStackOffset = GetMaxStackOffset())
- HandleFeature(FirstFeature + MaxStackOffset / 128);
+ HandleFeature(FirstFeature + StackDepthStepFunction(MaxStackOffset / 8));
}
extern TracePC TPC;