[SanitizerCoverage] Add stack depth tracing instrumentation.

Summary:
Augment SanitizerCoverage to insert maximum stack depth tracing for
use by libFuzzer.  The new instrumentation is enabled by the flag
-fsanitize-coverage=stack-depth and is compatible with the existing
trace-pc-guard coverage.  The user must also declare the following
global variable in their code:
  thread_local uintptr_t __sancov_lowest_stack

https://bugs.llvm.org/show_bug.cgi?id=33857

Reviewers: vitalybuka, kcc

Reviewed By: vitalybuka

Subscribers: kubamracek, hiraditya, cfe-commits, llvm-commits

Differential Revision: https://reviews.llvm.org/D36839

llvm-svn: 311186

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index a3473e4f223..24a08e84dc4 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -795,6 +795,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SanitizeCoverageInline8bitCounters =
       Args.hasArg(OPT_fsanitize_coverage_inline_8bit_counters);
   Opts.SanitizeCoveragePCTable = Args.hasArg(OPT_fsanitize_coverage_pc_table);
+  Opts.SanitizeCoverageStackDepth =
+      Args.hasArg(OPT_fsanitize_coverage_stack_depth);
   Opts.SanitizeMemoryTrackOrigins =
       getLastArgIntValue(Args, OPT_fsanitize_memory_track_origins_EQ, 0, Diags);
   Opts.SanitizeMemoryUseAfterDtor =