3 files changed, 46 insertions, 14 deletions

diff --git a/compiler-rt/lib/asan/asan_globals.cc b/compiler-rt/lib/asan/asan_globals.cc
index ac89d755e44..317d939fc83 100644
--- a/compiler-rt/lib/asan/asan_globals.cc
+++ b/compiler-rt/lib/asan/asan_globals.cc
@@ -21,15 +21,19 @@
 #include "asan_thread.h"
 
 #include <ctype.h>
-#include <map>
 
 namespace __asan {
 
 typedef __asan_global Global;
 
+struct ListOfGlobals {
+  const Global *g;
+  ListOfGlobals *next;
+};
+
 static AsanLock mu_for_globals(LINKER_INITIALIZED);
-typedef std::map<uintptr_t, Global> MapOfGlobals;
-static MapOfGlobals *g_all_globals = NULL;
+static ListOfGlobals *list_of_globals;
+static LowLevelAllocator allocator_for_globals(LINKER_INITIALIZED);
 
 void PoisonRedZones(const Global &g)  {
   size_t shadow_rz_size = kGlobalAndStackRedzone >> SHADOW_SCALE;
@@ -86,13 +90,9 @@ bool DescribeAddrIfMyRedZone(const Global &g, uintptr_t addr) {
 bool DescribeAddrIfGlobal(uintptr_t addr) {
   if (!FLAG_report_globals) return false;
   ScopedLock lock(&mu_for_globals);
-  if (!g_all_globals) return false;
   bool res = false;
-  // Just iterate. May want to use binary search instead.
-  for (MapOfGlobals::iterator i = g_all_globals->begin(),
-       end = g_all_globals->end(); i != end; ++i) {
-    Global &g = i->second;
-    CHECK(i->first == g.beg);
+  for (ListOfGlobals *l = list_of_globals; l; l = l->next) {
+    const Global &g = *l->g;
     if (FLAG_report_globals >= 2)
       Printf("Search Global: beg=%p size=%ld name=%s\n",
              g.beg, g.size, g.name);
@@ -108,15 +108,17 @@ static void RegisterGlobal(const Global *g) {
   CHECK(asan_inited);
   if (!FLAG_report_globals) return;
   ScopedLock lock(&mu_for_globals);
-  if (!g_all_globals)
-    g_all_globals = new MapOfGlobals;
   CHECK(AddrIsInMem(g->beg));
+  CHECK(AddrIsAlignedByGranularity(g->beg));
+  PoisonRedZones(*g);
+  ListOfGlobals *l =
+      (ListOfGlobals*)allocator_for_globals.Allocate(sizeof(ListOfGlobals));
+  l->g = g;
+  l->next = list_of_globals;
+  list_of_globals = l;
   if (FLAG_report_globals >= 2)
     Printf("Added Global: beg=%p size=%ld name=%s\n",
            g->beg, g->size, g->name);
-  CHECK(AddrIsAlignedByGranularity(g->beg));
-  PoisonRedZones(*g);
-  (*g_all_globals)[g->beg] = *g;
 }
 
 }  // namespace __asan
diff --git a/compiler-rt/lib/asan/asan_internal.h b/compiler-rt/lib/asan/asan_internal.h
index c722feb7b42..4ae68e78eca 100644
--- a/compiler-rt/lib/asan/asan_internal.h
+++ b/compiler-rt/lib/asan/asan_internal.h
@@ -163,6 +163,19 @@ const int kAsanGlobalRedzoneMagic = 0xf9;
 static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
 static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
 
+// -------------------------- LowLevelAllocator ----- {{{1
+// A simple low-level memory allocator for internal use.
+class LowLevelAllocator {
+ public:
+  explicit LowLevelAllocator(LinkerInitialized) {}
+  // 'size' must be a power of two.
+  // Requires an external lock.
+  void *Allocate(size_t size);
+ private:
+  char *allocated_end_;
+  char *allocated_current_;
+};
+
 // -------------------------- Atomic ---------------- {{{1
 static inline int AtomicInc(int *a) {
   if (!FLAG_mt) return ++(*a);
diff --git a/compiler-rt/lib/asan/asan_rtl.cc b/compiler-rt/lib/asan/asan_rtl.cc
index 5518641a67d..609c007cc52 100644
--- a/compiler-rt/lib/asan/asan_rtl.cc
+++ b/compiler-rt/lib/asan/asan_rtl.cc
@@ -174,6 +174,23 @@ static void protect_range(uintptr_t beg, uintptr_t end) {
   CHECK(res == (void*)beg);
 }
 
+// ---------------------- LowLevelAllocator ------------- {{{1
+void *LowLevelAllocator::Allocate(size_t size) {
+  CHECK((size & (size - 1)) == 0 && "size must be a power of two");
+  if (allocated_end_ - allocated_current_ < size) {
+    size_t size_to_allocate = Max(size, kPageSize);
+    allocated_current_ = (char*)asan_mmap(0, size_to_allocate,
+                                          PROT_READ | PROT_WRITE,
+                                          MAP_PRIVATE | MAP_ANON, -1, 0);
+    CHECK((allocated_current_ != (char*)-1) && "Can't mmap");
+    allocated_end_ = allocated_current_ + size_to_allocate;
+  }
+  CHECK(allocated_end_ - allocated_current_ >= size);
+  void *res = allocated_current_;
+  allocated_current_ += size;
+  return res;
+}
+
 // ---------------------- DescribeAddress -------------------- {{{1
 static bool DescribeStackAddress(uintptr_t addr, uintptr_t access_size) {
   AsanThread *t = asanThreadRegistry().FindThreadByStackAddress(addr);