[asan/tracing] extend the test a bit more, simplify the tracing code, add a guard page to trace array, fix the trace IDs before dumping

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@225108 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 33 insertions, 20 deletions

diff --git a/lib/sanitizer_common/sanitizer_coverage_libcdep.cc b/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
index 0639dc090..2a6b4d122 100644
--- a/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
+++ b/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
@@ -165,9 +165,12 @@ void CoverageData::Init() {
   atomic_store(&cc_array_size, kCcArrayMaxSize, memory_order_relaxed);
   atomic_store(&cc_array_index, 0, memory_order_relaxed);
 
-  tr_event_array = reinterpret_cast<u32 *>(
-      MmapNoReserveOrDie(sizeof(tr_event_array[0]) * kTrEventArrayMaxSize,
-                         "CovInit::tr_event_array"));
+  // Allocate tr_event_array with a guard page at the end.
+  tr_event_array = reinterpret_cast<u32 *>(MmapNoReserveOrDie(
+      sizeof(tr_event_array[0]) * kTrEventArrayMaxSize + GetMmapGranularity(),
+      "CovInit::tr_event_array"));
+  Mprotect(reinterpret_cast<uptr>(&tr_event_array[kTrEventArrayMaxSize]),
+           GetMmapGranularity());
   tr_event_array_size = kTrEventArrayMaxSize;
   tr_event_array_index = 0;
 }
@@ -416,6 +419,8 @@ void CoverageData::DumpTrace() {
 
   fd = CovOpenFile(false, "trace-events");
   if (fd < 0) return;
+  for (uptr i = 0; i < max_idx; i++)
+    tr_event_array[i]--;  // Fix the IDs.
   internal_write(fd, tr_event_array, max_idx * sizeof(tr_event_array[0]));
   internal_close(fd);
   VReport(1, " CovDump: Trace: %zd PCs written\n", size());
@@ -464,12 +469,16 @@ void CoverageData::DumpCallerCalleePairs() {
 // Record the current PC into the event buffer.
 // Every event is a u32 value (index in tr_pc_array_index) so we compute
 // it once and then cache in the provided 'cache' storage.
+//
+// This function will eventually be inlined by the compiler.
 void CoverageData::TraceBasicBlock(s32 *id) {
-  CHECK(coverage_enabled);
-  uptr idx = *id;
-  CHECK_LT(tr_event_array_index, tr_event_array_size);
-  tr_event_array[tr_event_array_index] = static_cast<u32>(idx);
-  tr_event_array_index++;
+  // CHECK(coverage_enabled);
+  // CHECK_LT(tr_event_array_index, tr_event_array_size);
+  //
+  // Will trap here if
+  //  1. coverage is not enabled at run-time.
+  //  2. The array tr_event_array is full.
+  tr_event_array[tr_event_array_index++] = static_cast<u32>(*id);
 }
 
 static void CovDumpAsBitSet() {
diff --git a/test/asan/TestCases/Linux/coverage-tracing.cc b/test/asan/TestCases/Linux/coverage-tracing.cc
index f696fb4f7..49dbb5e95 100644
--- a/test/asan/TestCases/Linux/coverage-tracing.cc
+++ b/test/asan/TestCases/Linux/coverage-tracing.cc
@@ -4,14 +4,14 @@
 // RUN: rm -rf   %T/coverage-tracing
 // RUN: mkdir %T/coverage-tracing
 // RUN: cd %T/coverage-tracing
-// RUN:  A=x;   ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK1; mv trace-points.*.sancov $A.points
-// RUN:  A=f;   ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK2; mv trace-points.*.sancov $A.points
-// RUN:  A=b;   ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK2; mv trace-points.*.sancov $A.points
-// RUN:  A=bf;  ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK3; mv trace-points.*.sancov $A.points
-// RUN:  A=fb;  ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK3; mv trace-points.*.sancov $A.points
-// RUN:  A=ffb; ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK4; mv trace-points.*.sancov $A.points
-// RUN:  A=fff; ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK4; mv trace-points.*.sancov $A.points
-// RUN:  A=bbf; ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK4; mv trace-points.*.sancov $A.points
+// RUN:  A=x;   ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK1; mv trace-points.*.sancov $A.points
+// RUN:  A=f;   ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK2; mv trace-points.*.sancov $A.points
+// RUN:  A=b;   ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK2; mv trace-points.*.sancov $A.points
+// RUN:  A=bf;  ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK3; mv trace-points.*.sancov $A.points
+// RUN:  A=fb;  ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK3; mv trace-points.*.sancov $A.points
+// RUN:  A=ffb; ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK4; mv trace-points.*.sancov $A.points
+// RUN:  A=fff; ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 1   2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK4; mv trace-points.*.sancov $A.points
+// RUN:  A=bbf; ASAN_OPTIONS=coverage=1:verbosity=1 %run %t $A 100 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK301; mv trace-points.*.sancov $A.points
 // RUN: diff f.points fff.points
 // RUN: diff bf.points fb.points
 // RUN: diff bf.points ffb.points
@@ -32,10 +32,13 @@ __attribute__((noinline)) void foo() { sink++; }
 __attribute__((noinline)) void bar() { sink++; }
 
 int main(int argc, char **argv) {
-  if (argc != 2) return 0;
-  for (int i = 0; argv[1][i]; i++) {
-    if (argv[1][i] == 'f') foo();
-    else if (argv[1][i] == 'b') bar();
+  if (argc != 3) return 0;
+  int n = strtol(argv[2], 0, 10);
+  while (n-- > 0) {
+    for (int i = 0; argv[1][i]; i++) {
+      if (argv[1][i] == 'f') foo();
+      else if (argv[1][i] == 'b') bar();
+    }
   }
 }
 
@@ -44,3 +47,4 @@ int main(int argc, char **argv) {
 // CHECK2: CovDump: Trace: 2 Events written
 // CHECK3: CovDump: Trace: 3 Events written
 // CHECK4: CovDump: Trace: 4 Events written
+// CHECK301: CovDump: Trace: 301 Events written