[libsanitizer] Unmapping the old cache partially invalidates the memory layout, so add

a flag to skip cache update for cases when that's unacceptable (e.g. lsan).

Patch by Sergey Matveev (earthdok@google.com)

llvm-svn: 178000

compiler-rt/lib/msan/msan.cc

@@ -70,7 +70,7 @@ namespace __msan {
 
 static bool IsRunningUnderDr() {
   bool result = false;
-  MemoryMappingLayout proc_maps;
+  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
   const sptr kBufSize = 4095;
   char *filename = (char*)MmapOrDie(kBufSize, __FUNCTION__);
   while (proc_maps.Next(/* start */0, /* end */0, /* file_offset */0,

compiler-rt/lib/sanitizer_common/sanitizer_linux.cc

@@ -200,7 +200,7 @@ void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
 
     // Find the mapping that contains a stack variable.
-    MemoryMappingLayout proc_maps;
+    MemoryMappingLayout proc_maps(/*cache_enabled*/true);
     uptr start, end, offset;
     uptr prev_end = 0;
     while (proc_maps.Next(&start, &end, &offset, 0, 0, /* protection */0)) {
@@ -341,18 +341,22 @@ void PrepareForSandboxing() {
 ProcSelfMapsBuff MemoryMappingLayout::cached_proc_self_maps_;
 StaticSpinMutex MemoryMappingLayout::cache_lock_;  // Linker initialized.
 
-MemoryMappingLayout::MemoryMappingLayout() {
+MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
   proc_self_maps_.len =
       ReadFileToBuffer("/proc/self/maps", &proc_self_maps_.data,
                        &proc_self_maps_.mmaped_size, 1 << 26);
-  if (proc_self_maps_.mmaped_size == 0) {
-    LoadFromCache();
-    CHECK_GT(proc_self_maps_.len, 0);
+  if (cache_enabled) {
+    if (proc_self_maps_.mmaped_size == 0) {
+      LoadFromCache();
+      CHECK_GT(proc_self_maps_.len, 0);
+    }
+  } else {
+    CHECK_GT(proc_self_maps_.mmaped_size, 0);
   }
-  // internal_write(2, proc_self_maps_.data, proc_self_maps_.len);
   Reset();
   // FIXME: in the future we may want to cache the mappings on demand only.
-  CacheMemoryMappings();
+  if (cache_enabled)
+    CacheMemoryMappings();
 }
 
 MemoryMappingLayout::~MemoryMappingLayout() {
@@ -643,7 +647,6 @@ int internal_sigaltstack(const struct sigaltstack *ss,
   return syscall(__NR_sigaltstack, ss, oss);
 }
 
-
 // ThreadLister implementation.
 ThreadLister::ThreadLister(int pid)
   : pid_(pid),

compiler-rt/lib/sanitizer_common/sanitizer_mac.cc

@@ -165,7 +165,7 @@ void PrepareForSandboxing() {
 
 // ----------------- sanitizer_procmaps.h
 
-MemoryMappingLayout::MemoryMappingLayout() {
+MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) {
   Reset();
 }
 

compiler-rt/lib/sanitizer_common/sanitizer_posix.cc

@@ -151,11 +151,11 @@ static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
 // several worker threads on Mac, which aren't expected to map big chunks of
 // memory).
 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
-  MemoryMappingLayout procmaps;
+  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
   uptr start, end;
-  while (procmaps.Next(&start, &end,
-                       /*offset*/0, /*filename*/0, /*filename_size*/0,
-                       /*protection*/0)) {
+  while (proc_maps.Next(&start, &end,
+                        /*offset*/0, /*filename*/0, /*filename_size*/0,
+                        /*protection*/0)) {
     if (!IntervalsAreSeparate(start, end, range_start, range_end))
       return false;
   }
@@ -163,7 +163,7 @@ bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
 }
 
 void DumpProcessMap() {
-  MemoryMappingLayout proc_maps;
+  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
   uptr start, end;
   const sptr kBufSize = 4095;
   char *filename = (char*)MmapOrDie(kBufSize, __FUNCTION__);

compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h

@@ -41,7 +41,7 @@ struct ProcSelfMapsBuff {
 
 class MemoryMappingLayout {
  public:
-  MemoryMappingLayout();
+  explicit MemoryMappingLayout(bool cache_enabled);
   bool Next(uptr *start, uptr *end, uptr *offset,
             char filename[], uptr filename_size, uptr *protection);
   void Reset();

compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc

@@ -64,7 +64,7 @@ static void PrintModuleAndOffset(const char *module, uptr offset,
 void StackTrace::PrintStack(const uptr *addr, uptr size,
                             bool symbolize, const char *strip_file_prefix,
                             SymbolizeCallback symbolize_callback ) {
-  MemoryMappingLayout proc_maps;
+  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
   InternalScopedBuffer<char> buff(GetPageSizeCached() * 2);
   InternalScopedBuffer<AddressInfo> addr_frames(64);
   uptr frame_num = 0;

compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc

@@ -198,7 +198,7 @@ static void MapRodata() {
     return;
   }
   // Map the file into shadow of .rodata sections.
-  MemoryMappingLayout proc_maps;
+  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
   uptr start, end, offset, prot;
   char name[128];
   while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), &prot)) {
@@ -257,7 +257,7 @@ static uptr g_data_end;
 #ifndef TSAN_GO
 static void CheckPIE() {
   // Ensure that the binary is indeed compiled with -pie.
-  MemoryMappingLayout proc_maps;
+  MemoryMappingLayout proc_maps(true);
   uptr start, end;
   if (proc_maps.Next(&start, &end,
                      /*offset*/0, /*filename*/0, /*filename_size*/0,
@@ -274,7 +274,7 @@ static void CheckPIE() {
 }
 
 static void InitDataSeg() {
-  MemoryMappingLayout proc_maps;
+  MemoryMappingLayout proc_maps(true);
   uptr start, end, offset;
   char name[128];
   bool prev_is_data = false;