forked from OSchip/llvm-project
809 lines
32 KiB
C++
809 lines
32 KiB
C++
//===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Coverage instrumentation that works with AddressSanitizer
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// and potentially with other Sanitizers.
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//
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// We create a Guard variable with the same linkage
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// as the function and inject this code into the entry block (SCK_Function)
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// or all blocks (SCK_BB):
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// if (Guard < 0) {
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// __sanitizer_cov(&Guard);
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// }
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// The accesses to Guard are atomic. The rest of the logic is
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// in __sanitizer_cov (it's fine to call it more than once).
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//
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// With SCK_Edge we also split critical edges this effectively
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// instrumenting all edges.
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//
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// This coverage implementation provides very limited data:
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// it only tells if a given function (block) was ever executed. No counters.
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// But for many use cases this is what we need and the added slowdown small.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Analysis/EHPersonalities.h"
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#include "llvm/Analysis/PostDominators.h"
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#include "llvm/IR/CFG.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DebugInfo.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InlineAsm.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Type.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Transforms/Instrumentation.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/ModuleUtils.h"
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using namespace llvm;
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#define DEBUG_TYPE "sancov"
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static const char *const SanCovModuleInitName = "__sanitizer_cov_module_init";
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static const char *const SanCovName = "__sanitizer_cov";
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static const char *const SanCovWithCheckName = "__sanitizer_cov_with_check";
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static const char *const SanCovIndirCallName = "__sanitizer_cov_indir_call16";
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static const char *const SanCovTracePCIndirName =
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"__sanitizer_cov_trace_pc_indir";
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static const char *const SanCovTraceEnterName =
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"__sanitizer_cov_trace_func_enter";
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static const char *const SanCovTraceBBName =
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"__sanitizer_cov_trace_basic_block";
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static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc";
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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 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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static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch";
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static const char *const SanCovModuleCtorName = "sancov.module_ctor";
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static const uint64_t SanCtorAndDtorPriority = 2;
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static const char *const SanCovTracePCGuardName =
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"__sanitizer_cov_trace_pc_guard";
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static const char *const SanCovTracePCGuardInitName =
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"__sanitizer_cov_trace_pc_guard_init";
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static cl::opt<int> ClCoverageLevel(
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"sanitizer-coverage-level",
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cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
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"3: all blocks and critical edges, "
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"4: above plus indirect calls"),
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cl::Hidden, cl::init(0));
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static cl::opt<unsigned> ClCoverageBlockThreshold(
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"sanitizer-coverage-block-threshold",
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cl::desc("Use a callback with a guard check inside it if there are"
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" more than this number of blocks."),
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cl::Hidden, cl::init(0));
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static cl::opt<bool>
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ClExperimentalTracing("sanitizer-coverage-experimental-tracing",
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cl::desc("Experimental basic-block tracing: insert "
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"callbacks at every basic block"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClExperimentalTracePC("sanitizer-coverage-trace-pc",
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cl::desc("Experimental pc tracing"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
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cl::desc("pc tracing with a guard"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool>
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ClCMPTracing("sanitizer-coverage-trace-compares",
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cl::desc("Tracing of CMP and similar instructions"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
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cl::desc("Tracing of DIV instructions"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
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cl::desc("Tracing of GEP instructions"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool>
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ClPruneBlocks("sanitizer-coverage-prune-blocks",
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cl::desc("Reduce the number of instrumented blocks"),
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cl::Hidden, cl::init(true));
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// Experimental 8-bit counters used as an additional search heuristic during
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// coverage-guided fuzzing.
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// The counters are not thread-friendly:
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// - contention on these counters may cause significant slowdown;
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// - the counter updates are racy and the results may be inaccurate.
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// They are also inaccurate due to 8-bit integer overflow.
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static cl::opt<bool> ClUse8bitCounters("sanitizer-coverage-8bit-counters",
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cl::desc("Experimental 8-bit counters"),
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cl::Hidden, cl::init(false));
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namespace {
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SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
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SanitizerCoverageOptions Res;
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switch (LegacyCoverageLevel) {
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case 0:
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Res.CoverageType = SanitizerCoverageOptions::SCK_None;
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break;
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case 1:
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Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
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break;
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case 2:
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Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
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break;
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case 3:
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Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
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break;
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case 4:
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Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
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Res.IndirectCalls = true;
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break;
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}
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return Res;
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}
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SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
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// Sets CoverageType and IndirectCalls.
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SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
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Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
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Options.IndirectCalls |= CLOpts.IndirectCalls;
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Options.TraceBB |= ClExperimentalTracing;
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Options.TraceCmp |= ClCMPTracing;
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Options.TraceDiv |= ClDIVTracing;
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Options.TraceGep |= ClGEPTracing;
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Options.Use8bitCounters |= ClUse8bitCounters;
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Options.TracePC |= ClExperimentalTracePC;
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Options.TracePCGuard |= ClTracePCGuard;
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return Options;
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}
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class SanitizerCoverageModule : public ModulePass {
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public:
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SanitizerCoverageModule(
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const SanitizerCoverageOptions &Options = SanitizerCoverageOptions())
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: ModulePass(ID), Options(OverrideFromCL(Options)) {
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initializeSanitizerCoverageModulePass(*PassRegistry::getPassRegistry());
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}
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bool runOnModule(Module &M) override;
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bool runOnFunction(Function &F);
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static char ID; // Pass identification, replacement for typeid
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StringRef getPassName() const override { return "SanitizerCoverageModule"; }
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addRequired<DominatorTreeWrapperPass>();
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AU.addRequired<PostDominatorTreeWrapperPass>();
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}
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private:
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void InjectCoverageForIndirectCalls(Function &F,
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ArrayRef<Instruction *> IndirCalls);
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void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
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void InjectTraceForDiv(Function &F,
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ArrayRef<BinaryOperator *> DivTraceTargets);
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void InjectTraceForGep(Function &F,
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ArrayRef<GetElementPtrInst *> GepTraceTargets);
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void InjectTraceForSwitch(Function &F,
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ArrayRef<Instruction *> SwitchTraceTargets);
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bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks);
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void CreateFunctionGuardArray(size_t NumGuards, Function &F);
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void SetNoSanitizeMetadata(Instruction *I);
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void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
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bool UseCalls);
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unsigned NumberOfInstrumentedBlocks() {
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return SanCovFunction->getNumUses() +
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SanCovWithCheckFunction->getNumUses() + SanCovTraceBB->getNumUses() +
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SanCovTraceEnter->getNumUses();
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}
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StringRef getSanCovTracePCGuardSection() const;
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StringRef getSanCovTracePCGuardSectionStart() const;
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StringRef getSanCovTracePCGuardSectionEnd() const;
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Function *SanCovFunction;
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Function *SanCovWithCheckFunction;
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Function *SanCovIndirCallFunction, *SanCovTracePCIndir;
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Function *SanCovTraceEnter, *SanCovTraceBB, *SanCovTracePC, *SanCovTracePCGuard;
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Function *SanCovTraceCmpFunction[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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Module *CurModule;
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Triple TargetTriple;
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LLVMContext *C;
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const DataLayout *DL;
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GlobalVariable *GuardArray;
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GlobalVariable *FunctionGuardArray; // for trace-pc-guard.
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GlobalVariable *EightBitCounterArray;
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bool HasSancovGuardsSection;
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SanitizerCoverageOptions Options;
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};
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} // namespace
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bool SanitizerCoverageModule::runOnModule(Module &M) {
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if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
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return false;
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C = &(M.getContext());
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DL = &M.getDataLayout();
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CurModule = &M;
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TargetTriple = Triple(M.getTargetTriple());
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HasSancovGuardsSection = false;
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IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
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IntptrPtrTy = PointerType::getUnqual(IntptrTy);
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Type *VoidTy = Type::getVoidTy(*C);
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IRBuilder<> IRB(*C);
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Type *Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
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Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
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Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
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Int64Ty = IRB.getInt64Ty();
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Int32Ty = IRB.getInt32Ty();
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SanCovFunction = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovName, VoidTy, Int32PtrTy, nullptr));
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SanCovWithCheckFunction = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovWithCheckName, VoidTy, Int32PtrTy, nullptr));
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SanCovTracePCIndir = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy, nullptr));
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SanCovIndirCallFunction =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr));
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SanCovTraceCmpFunction[0] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceCmp1, VoidTy, IRB.getInt8Ty(), IRB.getInt8Ty(), nullptr));
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SanCovTraceCmpFunction[1] = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovTraceCmp2, VoidTy, IRB.getInt16Ty(),
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IRB.getInt16Ty(), nullptr));
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SanCovTraceCmpFunction[2] = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovTraceCmp4, VoidTy, IRB.getInt32Ty(),
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IRB.getInt32Ty(), nullptr));
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SanCovTraceCmpFunction[3] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty, nullptr));
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SanCovTraceDivFunction[0] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceDiv4, VoidTy, IRB.getInt32Ty(), nullptr));
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SanCovTraceDivFunction[1] =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceDiv8, VoidTy, Int64Ty, nullptr));
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SanCovTraceGepFunction =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceGep, VoidTy, IntptrTy, nullptr));
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SanCovTraceSwitchFunction =
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checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy, nullptr));
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// We insert an empty inline asm after cov callbacks to avoid callback merge.
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EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
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StringRef(""), StringRef(""),
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/*hasSideEffects=*/true);
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SanCovTracePC = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovTracePCName, VoidTy, nullptr));
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SanCovTracePCGuard = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
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SanCovTracePCGuardName, VoidTy, Int32PtrTy, nullptr));
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SanCovTraceEnter = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovTraceEnterName, VoidTy, Int32PtrTy, nullptr));
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SanCovTraceBB = checkSanitizerInterfaceFunction(
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M.getOrInsertFunction(SanCovTraceBBName, VoidTy, Int32PtrTy, nullptr));
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// At this point we create a dummy array of guards because we don't
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// know how many elements we will need.
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Type *Int32Ty = IRB.getInt32Ty();
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Type *Int8Ty = IRB.getInt8Ty();
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if (!Options.TracePCGuard)
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GuardArray =
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new GlobalVariable(M, Int32Ty, false, GlobalValue::ExternalLinkage,
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nullptr, "__sancov_gen_cov_tmp");
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if (Options.Use8bitCounters)
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EightBitCounterArray =
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new GlobalVariable(M, Int8Ty, false, GlobalVariable::ExternalLinkage,
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nullptr, "__sancov_gen_cov_tmp");
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for (auto &F : M)
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runOnFunction(F);
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auto N = NumberOfInstrumentedBlocks();
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GlobalVariable *RealGuardArray = nullptr;
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if (!Options.TracePCGuard) {
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// Now we know how many elements we need. Create an array of guards
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// with one extra element at the beginning for the size.
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Type *Int32ArrayNTy = ArrayType::get(Int32Ty, N + 1);
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RealGuardArray = new GlobalVariable(
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M, Int32ArrayNTy, false, GlobalValue::PrivateLinkage,
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Constant::getNullValue(Int32ArrayNTy), "__sancov_gen_cov");
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// Replace the dummy array with the real one.
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GuardArray->replaceAllUsesWith(
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IRB.CreatePointerCast(RealGuardArray, Int32PtrTy));
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GuardArray->eraseFromParent();
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}
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GlobalVariable *RealEightBitCounterArray;
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if (Options.Use8bitCounters) {
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// Make sure the array is 16-aligned.
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static const int CounterAlignment = 16;
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Type *Int8ArrayNTy = ArrayType::get(Int8Ty, alignTo(N, CounterAlignment));
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RealEightBitCounterArray = new GlobalVariable(
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M, Int8ArrayNTy, false, GlobalValue::PrivateLinkage,
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Constant::getNullValue(Int8ArrayNTy), "__sancov_gen_cov_counter");
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RealEightBitCounterArray->setAlignment(CounterAlignment);
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EightBitCounterArray->replaceAllUsesWith(
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IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy));
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EightBitCounterArray->eraseFromParent();
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}
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// Create variable for module (compilation unit) name
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Constant *ModNameStrConst =
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ConstantDataArray::getString(M.getContext(), M.getName(), true);
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GlobalVariable *ModuleName = new GlobalVariable(
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M, ModNameStrConst->getType(), true, GlobalValue::PrivateLinkage,
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ModNameStrConst, "__sancov_gen_modname");
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if (Options.TracePCGuard) {
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if (HasSancovGuardsSection) {
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Function *CtorFunc;
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GlobalVariable *SecStart = new GlobalVariable(
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M, Int32PtrTy, false, GlobalVariable::ExternalLinkage, nullptr,
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getSanCovTracePCGuardSectionStart());
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SecStart->setVisibility(GlobalValue::HiddenVisibility);
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GlobalVariable *SecEnd = new GlobalVariable(
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M, Int32PtrTy, false, GlobalVariable::ExternalLinkage, nullptr,
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getSanCovTracePCGuardSectionEnd());
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SecEnd->setVisibility(GlobalValue::HiddenVisibility);
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std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
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M, SanCovModuleCtorName, SanCovTracePCGuardInitName,
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{Int32PtrTy, Int32PtrTy},
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{IRB.CreatePointerCast(SecStart, Int32PtrTy),
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IRB.CreatePointerCast(SecEnd, Int32PtrTy)});
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if (TargetTriple.supportsCOMDAT()) {
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// Use comdat to dedup CtorFunc.
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CtorFunc->setComdat(M.getOrInsertComdat(SanCovModuleCtorName));
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appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
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} else {
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appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
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}
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}
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} else if (!Options.TracePC) {
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Function *CtorFunc;
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std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
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M, SanCovModuleCtorName, SanCovModuleInitName,
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{Int32PtrTy, IntptrTy, Int8PtrTy, Int8PtrTy},
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{IRB.CreatePointerCast(RealGuardArray, Int32PtrTy),
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ConstantInt::get(IntptrTy, N),
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Options.Use8bitCounters
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? IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy)
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: Constant::getNullValue(Int8PtrTy),
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IRB.CreatePointerCast(ModuleName, Int8PtrTy)});
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appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
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}
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return true;
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}
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// True if block has successors and it dominates all of them.
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static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
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if (succ_begin(BB) == succ_end(BB))
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return false;
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for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) {
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if (!DT->dominates(BB, SUCC))
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return false;
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}
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return true;
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}
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// True if block has predecessors and it postdominates all of them.
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static bool isFullPostDominator(const BasicBlock *BB,
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const PostDominatorTree *PDT) {
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if (pred_begin(BB) == pred_end(BB))
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|
return false;
|
|
|
|
for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) {
|
|
if (!PDT->dominates(BB, PRED))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool shouldInstrumentBlock(const Function& F, const BasicBlock *BB, const DominatorTree *DT,
|
|
const PostDominatorTree *PDT) {
|
|
// Don't insert coverage for unreachable blocks: we will never call
|
|
// __sanitizer_cov() for them, so counting them in
|
|
// NumberOfInstrumentedBlocks() might complicate calculation of code coverage
|
|
// percentage. Also, unreachable instructions frequently have no debug
|
|
// locations.
|
|
if (isa<UnreachableInst>(BB->getTerminator()))
|
|
return false;
|
|
|
|
// Don't insert coverage into blocks without a valid insertion point
|
|
// (catchswitch blocks).
|
|
if (BB->getFirstInsertionPt() == BB->end())
|
|
return false;
|
|
|
|
if (!ClPruneBlocks || &F.getEntryBlock() == BB)
|
|
return true;
|
|
|
|
return !(isFullDominator(BB, DT) || isFullPostDominator(BB, PDT));
|
|
}
|
|
|
|
bool SanitizerCoverageModule::runOnFunction(Function &F) {
|
|
if (F.empty())
|
|
return false;
|
|
if (F.getName().find(".module_ctor") != std::string::npos)
|
|
return false; // Should not instrument sanitizer init functions.
|
|
if (F.getName().startswith("__sanitizer_"))
|
|
return false; // Don't instrument __sanitizer_* callbacks.
|
|
// Don't instrument MSVC CRT configuration helpers. They may run before normal
|
|
// initialization.
|
|
if (F.getName() == "__local_stdio_printf_options" ||
|
|
F.getName() == "__local_stdio_scanf_options")
|
|
return false;
|
|
// Don't instrument functions using SEH for now. Splitting basic blocks like
|
|
// we do for coverage breaks WinEHPrepare.
|
|
// FIXME: Remove this when SEH no longer uses landingpad pattern matching.
|
|
if (F.hasPersonalityFn() &&
|
|
isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
|
|
return false;
|
|
if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
|
|
SplitAllCriticalEdges(F);
|
|
SmallVector<Instruction *, 8> IndirCalls;
|
|
SmallVector<BasicBlock *, 16> BlocksToInstrument;
|
|
SmallVector<Instruction *, 8> CmpTraceTargets;
|
|
SmallVector<Instruction *, 8> SwitchTraceTargets;
|
|
SmallVector<BinaryOperator *, 8> DivTraceTargets;
|
|
SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
|
|
|
|
const DominatorTree *DT =
|
|
&getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
|
|
const PostDominatorTree *PDT =
|
|
&getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree();
|
|
|
|
for (auto &BB : F) {
|
|
if (shouldInstrumentBlock(F, &BB, DT, PDT))
|
|
BlocksToInstrument.push_back(&BB);
|
|
for (auto &Inst : BB) {
|
|
if (Options.IndirectCalls) {
|
|
CallSite CS(&Inst);
|
|
if (CS && !CS.getCalledFunction())
|
|
IndirCalls.push_back(&Inst);
|
|
}
|
|
if (Options.TraceCmp) {
|
|
if (isa<ICmpInst>(&Inst))
|
|
CmpTraceTargets.push_back(&Inst);
|
|
if (isa<SwitchInst>(&Inst))
|
|
SwitchTraceTargets.push_back(&Inst);
|
|
}
|
|
if (Options.TraceDiv)
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
|
|
if (BO->getOpcode() == Instruction::SDiv ||
|
|
BO->getOpcode() == Instruction::UDiv)
|
|
DivTraceTargets.push_back(BO);
|
|
if (Options.TraceGep)
|
|
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
|
|
GepTraceTargets.push_back(GEP);
|
|
}
|
|
}
|
|
|
|
InjectCoverage(F, BlocksToInstrument);
|
|
InjectCoverageForIndirectCalls(F, IndirCalls);
|
|
InjectTraceForCmp(F, CmpTraceTargets);
|
|
InjectTraceForSwitch(F, SwitchTraceTargets);
|
|
InjectTraceForDiv(F, DivTraceTargets);
|
|
InjectTraceForGep(F, GepTraceTargets);
|
|
return true;
|
|
}
|
|
void SanitizerCoverageModule::CreateFunctionGuardArray(size_t NumGuards,
|
|
Function &F) {
|
|
if (!Options.TracePCGuard) return;
|
|
HasSancovGuardsSection = true;
|
|
ArrayType *ArrayOfInt32Ty = ArrayType::get(Int32Ty, NumGuards);
|
|
FunctionGuardArray = new GlobalVariable(
|
|
*CurModule, ArrayOfInt32Ty, false, GlobalVariable::PrivateLinkage,
|
|
Constant::getNullValue(ArrayOfInt32Ty), "__sancov_gen_");
|
|
if (auto Comdat = F.getComdat())
|
|
FunctionGuardArray->setComdat(Comdat);
|
|
FunctionGuardArray->setSection(getSanCovTracePCGuardSection());
|
|
}
|
|
|
|
bool SanitizerCoverageModule::InjectCoverage(Function &F,
|
|
ArrayRef<BasicBlock *> AllBlocks) {
|
|
if (AllBlocks.empty()) return false;
|
|
switch (Options.CoverageType) {
|
|
case SanitizerCoverageOptions::SCK_None:
|
|
return false;
|
|
case SanitizerCoverageOptions::SCK_Function:
|
|
CreateFunctionGuardArray(1, F);
|
|
InjectCoverageAtBlock(F, F.getEntryBlock(), 0, false);
|
|
return true;
|
|
default: {
|
|
bool UseCalls = ClCoverageBlockThreshold < AllBlocks.size();
|
|
CreateFunctionGuardArray(AllBlocks.size(), F);
|
|
for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
|
|
InjectCoverageAtBlock(F, *AllBlocks[i], i, UseCalls);
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
// On every indirect call we call a run-time function
|
|
// __sanitizer_cov_indir_call* with two parameters:
|
|
// - callee address,
|
|
// - global cache array that contains CacheSize pointers (zero-initialized).
|
|
// The cache is used to speed up recording the caller-callee pairs.
|
|
// The address of the caller is passed implicitly via caller PC.
|
|
// CacheSize is encoded in the name of the run-time function.
|
|
void SanitizerCoverageModule::InjectCoverageForIndirectCalls(
|
|
Function &F, ArrayRef<Instruction *> IndirCalls) {
|
|
if (IndirCalls.empty())
|
|
return;
|
|
const int CacheSize = 16;
|
|
const int CacheAlignment = 64; // Align for better performance.
|
|
Type *Ty = ArrayType::get(IntptrTy, CacheSize);
|
|
for (auto I : IndirCalls) {
|
|
IRBuilder<> IRB(I);
|
|
CallSite CS(I);
|
|
Value *Callee = CS.getCalledValue();
|
|
if (isa<InlineAsm>(Callee))
|
|
continue;
|
|
GlobalVariable *CalleeCache = new GlobalVariable(
|
|
*F.getParent(), Ty, false, GlobalValue::PrivateLinkage,
|
|
Constant::getNullValue(Ty), "__sancov_gen_callee_cache");
|
|
CalleeCache->setAlignment(CacheAlignment);
|
|
if (Options.TracePC || Options.TracePCGuard)
|
|
IRB.CreateCall(SanCovTracePCIndir,
|
|
IRB.CreatePointerCast(Callee, IntptrTy));
|
|
else
|
|
IRB.CreateCall(SanCovIndirCallFunction,
|
|
{IRB.CreatePointerCast(Callee, IntptrTy),
|
|
IRB.CreatePointerCast(CalleeCache, IntptrTy)});
|
|
}
|
|
}
|
|
|
|
// For every switch statement we insert a call:
|
|
// __sanitizer_cov_trace_switch(CondValue,
|
|
// {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
|
|
|
|
void SanitizerCoverageModule::InjectTraceForSwitch(
|
|
Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
|
|
for (auto I : SwitchTraceTargets) {
|
|
if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
|
|
IRBuilder<> IRB(I);
|
|
SmallVector<Constant *, 16> Initializers;
|
|
Value *Cond = SI->getCondition();
|
|
if (Cond->getType()->getScalarSizeInBits() >
|
|
Int64Ty->getScalarSizeInBits())
|
|
continue;
|
|
Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
|
|
Initializers.push_back(
|
|
ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
|
|
if (Cond->getType()->getScalarSizeInBits() <
|
|
Int64Ty->getScalarSizeInBits())
|
|
Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
|
|
for (auto It : SI->cases()) {
|
|
Constant *C = It.getCaseValue();
|
|
if (C->getType()->getScalarSizeInBits() <
|
|
Int64Ty->getScalarSizeInBits())
|
|
C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
|
|
Initializers.push_back(C);
|
|
}
|
|
std::sort(Initializers.begin() + 2, Initializers.end(),
|
|
[](const Constant *A, const Constant *B) {
|
|
return cast<ConstantInt>(A)->getLimitedValue() <
|
|
cast<ConstantInt>(B)->getLimitedValue();
|
|
});
|
|
ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
|
|
GlobalVariable *GV = new GlobalVariable(
|
|
*CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
|
|
ConstantArray::get(ArrayOfInt64Ty, Initializers),
|
|
"__sancov_gen_cov_switch_values");
|
|
IRB.CreateCall(SanCovTraceSwitchFunction,
|
|
{Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
|
|
}
|
|
}
|
|
}
|
|
|
|
void SanitizerCoverageModule::InjectTraceForDiv(
|
|
Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
|
|
for (auto BO : DivTraceTargets) {
|
|
IRBuilder<> IRB(BO);
|
|
Value *A1 = BO->getOperand(1);
|
|
if (isa<ConstantInt>(A1)) continue;
|
|
if (!A1->getType()->isIntegerTy())
|
|
continue;
|
|
uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
|
|
int CallbackIdx = TypeSize == 32 ? 0 :
|
|
TypeSize == 64 ? 1 : -1;
|
|
if (CallbackIdx < 0) continue;
|
|
auto Ty = Type::getIntNTy(*C, TypeSize);
|
|
IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
|
|
{IRB.CreateIntCast(A1, Ty, true)});
|
|
}
|
|
}
|
|
|
|
void SanitizerCoverageModule::InjectTraceForGep(
|
|
Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
|
|
for (auto GEP : GepTraceTargets) {
|
|
IRBuilder<> IRB(GEP);
|
|
for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I)
|
|
if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy())
|
|
IRB.CreateCall(SanCovTraceGepFunction,
|
|
{IRB.CreateIntCast(*I, IntptrTy, true)});
|
|
}
|
|
}
|
|
|
|
void SanitizerCoverageModule::InjectTraceForCmp(
|
|
Function &, ArrayRef<Instruction *> CmpTraceTargets) {
|
|
for (auto I : CmpTraceTargets) {
|
|
if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
|
|
IRBuilder<> IRB(ICMP);
|
|
Value *A0 = ICMP->getOperand(0);
|
|
Value *A1 = ICMP->getOperand(1);
|
|
if (!A0->getType()->isIntegerTy())
|
|
continue;
|
|
uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
|
|
int CallbackIdx = TypeSize == 8 ? 0 :
|
|
TypeSize == 16 ? 1 :
|
|
TypeSize == 32 ? 2 :
|
|
TypeSize == 64 ? 3 : -1;
|
|
if (CallbackIdx < 0) continue;
|
|
// __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
|
|
auto Ty = Type::getIntNTy(*C, TypeSize);
|
|
IRB.CreateCall(
|
|
SanCovTraceCmpFunction[CallbackIdx],
|
|
{IRB.CreateIntCast(A0, Ty, true), IRB.CreateIntCast(A1, Ty, true)});
|
|
}
|
|
}
|
|
}
|
|
|
|
void SanitizerCoverageModule::SetNoSanitizeMetadata(Instruction *I) {
|
|
I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
|
|
MDNode::get(*C, None));
|
|
}
|
|
|
|
void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
|
|
size_t Idx, bool UseCalls) {
|
|
BasicBlock::iterator IP = BB.getFirstInsertionPt();
|
|
bool IsEntryBB = &BB == &F.getEntryBlock();
|
|
DebugLoc EntryLoc;
|
|
if (IsEntryBB) {
|
|
if (auto SP = F.getSubprogram())
|
|
EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
|
|
// Keep static allocas and llvm.localescape calls in the entry block. Even
|
|
// if we aren't splitting the block, it's nice for allocas to be before
|
|
// calls.
|
|
IP = PrepareToSplitEntryBlock(BB, IP);
|
|
} else {
|
|
EntryLoc = IP->getDebugLoc();
|
|
}
|
|
|
|
IRBuilder<> IRB(&*IP);
|
|
IRB.SetCurrentDebugLocation(EntryLoc);
|
|
if (Options.TracePC) {
|
|
IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC.
|
|
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
|
|
} else if (Options.TracePCGuard) {
|
|
auto GuardPtr = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy),
|
|
ConstantInt::get(IntptrTy, Idx * 4)),
|
|
Int32PtrTy);
|
|
if (!UseCalls) {
|
|
auto GuardLoad = IRB.CreateLoad(GuardPtr);
|
|
GuardLoad->setAtomic(AtomicOrdering::Monotonic);
|
|
GuardLoad->setAlignment(8);
|
|
SetNoSanitizeMetadata(GuardLoad); // Don't instrument with e.g. asan.
|
|
auto Cmp = IRB.CreateICmpNE(
|
|
GuardLoad, Constant::getNullValue(GuardLoad->getType()));
|
|
auto Ins = SplitBlockAndInsertIfThen(
|
|
Cmp, &*IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
|
|
IRB.SetInsertPoint(Ins);
|
|
IRB.SetCurrentDebugLocation(EntryLoc);
|
|
}
|
|
IRB.CreateCall(SanCovTracePCGuard, GuardPtr);
|
|
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
|
|
} else {
|
|
Value *GuardP = IRB.CreateAdd(
|
|
IRB.CreatePointerCast(GuardArray, IntptrTy),
|
|
ConstantInt::get(IntptrTy, (1 + NumberOfInstrumentedBlocks()) * 4));
|
|
GuardP = IRB.CreateIntToPtr(GuardP, Int32PtrTy);
|
|
if (Options.TraceBB) {
|
|
IRB.CreateCall(IsEntryBB ? SanCovTraceEnter : SanCovTraceBB, GuardP);
|
|
} else if (UseCalls) {
|
|
IRB.CreateCall(SanCovWithCheckFunction, GuardP);
|
|
} else {
|
|
LoadInst *Load = IRB.CreateLoad(GuardP);
|
|
Load->setAtomic(AtomicOrdering::Monotonic);
|
|
Load->setAlignment(4);
|
|
SetNoSanitizeMetadata(Load);
|
|
Value *Cmp =
|
|
IRB.CreateICmpSGE(Constant::getNullValue(Load->getType()), Load);
|
|
Instruction *Ins = SplitBlockAndInsertIfThen(
|
|
Cmp, &*IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
|
|
IRB.SetInsertPoint(Ins);
|
|
IRB.SetCurrentDebugLocation(EntryLoc);
|
|
// __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
|
|
IRB.CreateCall(SanCovFunction, GuardP);
|
|
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
|
|
}
|
|
}
|
|
|
|
if (Options.Use8bitCounters) {
|
|
IRB.SetInsertPoint(&*IP);
|
|
Value *P = IRB.CreateAdd(
|
|
IRB.CreatePointerCast(EightBitCounterArray, IntptrTy),
|
|
ConstantInt::get(IntptrTy, NumberOfInstrumentedBlocks() - 1));
|
|
P = IRB.CreateIntToPtr(P, IRB.getInt8PtrTy());
|
|
LoadInst *LI = IRB.CreateLoad(P);
|
|
Value *Inc = IRB.CreateAdd(LI, ConstantInt::get(IRB.getInt8Ty(), 1));
|
|
StoreInst *SI = IRB.CreateStore(Inc, P);
|
|
SetNoSanitizeMetadata(LI);
|
|
SetNoSanitizeMetadata(SI);
|
|
}
|
|
}
|
|
|
|
StringRef SanitizerCoverageModule::getSanCovTracePCGuardSection() const {
|
|
if (TargetTriple.getObjectFormat() == Triple::COFF)
|
|
return ".SCOV$M";
|
|
if (TargetTriple.isOSBinFormatMachO())
|
|
return "__DATA,__sancov_guards";
|
|
return "__sancov_guards";
|
|
}
|
|
|
|
StringRef SanitizerCoverageModule::getSanCovTracePCGuardSectionStart() const {
|
|
if (TargetTriple.isOSBinFormatMachO())
|
|
return "\1section$start$__DATA$__sancov_guards";
|
|
return "__start___sancov_guards";
|
|
}
|
|
|
|
StringRef SanitizerCoverageModule::getSanCovTracePCGuardSectionEnd() const {
|
|
if (TargetTriple.isOSBinFormatMachO())
|
|
return "\1section$end$__DATA$__sancov_guards";
|
|
return "__stop___sancov_guards";
|
|
}
|
|
|
|
|
|
char SanitizerCoverageModule::ID = 0;
|
|
INITIALIZE_PASS_BEGIN(SanitizerCoverageModule, "sancov",
|
|
"SanitizerCoverage: TODO."
|
|
"ModulePass",
|
|
false, false)
|
|
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
|
|
INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
|
|
INITIALIZE_PASS_END(SanitizerCoverageModule, "sancov",
|
|
"SanitizerCoverage: TODO."
|
|
"ModulePass",
|
|
false, false)
|
|
ModulePass *llvm::createSanitizerCoverageModulePass(
|
|
const SanitizerCoverageOptions &Options) {
|
|
return new SanitizerCoverageModule(Options);
|
|
}
|