[sanitizer-coverage] implement -fsanitize-coverage=no-prune,... instead of a hidden -mllvm flag. clang part.

llvm-svn: 302320

clang/docs/SanitizerCoverage.rst

@@ -144,8 +144,9 @@ Use these flags together with ``trace-pc-guard`` or ``trace-pc``,
 like this: ``-fsanitize-coverage=func,trace-pc-guard``.
 
 When ``edge`` or ``bb`` is used, some of the edges/blocks may still be left
-uninstrumented if such instrumentation is considered redundant.
-**TODO**: add a user-visible option to disable the optimization.
+uninstrumented (pruned) if such instrumentation is considered redundant.
+Use ``no-prune`` (e.g. ``-fsanitize-coverage=bb,no-prune,trace-pc-guard``)
+to disable pruning. This could be useful for better coverage visualization.
 
 
 Edge coverage

clang/include/clang/Driver/CC1Options.td

@@ -297,6 +297,9 @@ def fsanitize_coverage_trace_pc
 def fsanitize_coverage_trace_pc_guard
     : Flag<["-"], "fsanitize-coverage-trace-pc-guard">,
       HelpText<"Enable PC tracing with guard in sanitizer coverage">;
+def fsanitize_coverage_no_prune
+    : Flag<["-"], "fsanitize-coverage-no-prune">,
+      HelpText<"Disable coverage pruning (i.e. instrument all blocks/edges)">;
 def fprofile_instrument_EQ : Joined<["-"], "fprofile-instrument=">,
     HelpText<"Enable PGO instrumentation. The accepted value is clang, llvm, "
              "or none">;

clang/include/clang/Frontend/CodeGenOptions.def

@@ -160,6 +160,7 @@ CODEGENOPT(SanitizeCoverageTracePC, 1, 0) ///< Enable PC tracing
                                           ///< in sanitizer coverage.
 CODEGENOPT(SanitizeCoverageTracePCGuard, 1, 0) ///< Enable PC tracing with guard
                                                ///< in sanitizer coverage.
+CODEGENOPT(SanitizeCoverageNoPrune, 1, 0) ///< Disable coverage pruning.
 CODEGENOPT(SanitizeStats     , 1, 0) ///< Collect statistics for sanitizers.
 CODEGENOPT(SimplifyLibCalls  , 1, 1) ///< Set when -fbuiltin is enabled.
 CODEGENOPT(SoftFloat         , 1, 0) ///< -soft-float.

clang/lib/CodeGen/BackendUtil.cpp

@@ -185,6 +185,7 @@ static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
+  Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
   PM.add(createSanitizerCoverageModulePass(Opts));
 }
 

clang/lib/Driver/SanitizerArgs.cpp

@@ -55,6 +55,7 @@ enum CoverageFeature {
   Coverage8bitCounters = 1 << 8,
   CoverageTracePC = 1 << 9,
   CoverageTracePCGuard = 1 << 10,
+  CoverageNoPrune = 1 << 11,
 };
 
 /// Parse a -fsanitize= or -fno-sanitize= argument's values, diagnosing any
@@ -629,7 +630,8 @@ void SanitizerArgs::addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
     std::make_pair(CoverageTraceGep, "-fsanitize-coverage-trace-gep"),
     std::make_pair(Coverage8bitCounters, "-fsanitize-coverage-8bit-counters"),
     std::make_pair(CoverageTracePC, "-fsanitize-coverage-trace-pc"),
-    std::make_pair(CoverageTracePCGuard, "-fsanitize-coverage-trace-pc-guard")};
+    std::make_pair(CoverageTracePCGuard, "-fsanitize-coverage-trace-pc-guard"),
+    std::make_pair(CoverageNoPrune, "-fsanitize-coverage-no-prune")};
   for (auto F : CoverageFlags) {
     if (CoverageFeatures & F.first)
       CmdArgs.push_back(Args.MakeArgString(F.second));
@@ -786,6 +788,7 @@ int parseCoverageFeatures(const Driver &D, const llvm::opt::Arg *A) {
         .Case("8bit-counters", Coverage8bitCounters)
         .Case("trace-pc", CoverageTracePC)
         .Case("trace-pc-guard", CoverageTracePCGuard)
+        .Case("no-prune", CoverageNoPrune)
         .Default(0);
     if (F == 0)
       D.Diag(clang::diag::err_drv_unsupported_option_argument)

clang/lib/Frontend/CompilerInvocation.cpp

@@ -766,6 +766,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SanitizeCoverageTracePC = Args.hasArg(OPT_fsanitize_coverage_trace_pc);
   Opts.SanitizeCoverageTracePCGuard =
       Args.hasArg(OPT_fsanitize_coverage_trace_pc_guard);
+  Opts.SanitizeCoverageNoPrune = Args.hasArg(OPT_fsanitize_coverage_no_prune);
   Opts.SanitizeMemoryTrackOrigins =
       getLastArgIntValue(Args, OPT_fsanitize_memory_track_origins_EQ, 0, Diags);
   Opts.SanitizeMemoryUseAfterDtor =

clang/test/Driver/fsanitize-coverage.c

@@ -80,6 +80,10 @@
 // CHECK-EXTEND-LEGACY: -fsanitize-coverage-type=1
 // CHECK-EXTEND-LEGACY: -fsanitize-coverage-trace-cmp
 
+// RUN: %clang -target x86_64-linux-gnu -fsanitize-coverage=no-prune,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK_NOPRUNE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize-coverage=no-prune,func,trace-pc-guard %s -### 2>&1 | FileCheck %s --check-prefix=CHECK_NOPRUNE
+// CHECK_NOPRUNE: -fsanitize-coverage-no-prune
+
 // RUN: %clang_cl --target=i386-pc-win32 -fsanitize=address -fsanitize-coverage=func,trace-pc-guard -c -### -- %s 2>&1 | FileCheck %s -check-prefix=CLANG-CL-COVERAGE
 // CLANG-CL-COVERAGE-NOT: error:
 // CLANG-CL-COVERAGE-NOT: warning: