[Sanitizer] Introduce ListOfModules object and use it to replace GetListOfModules().

Summary:
This removes the hard limit on the number of loaded modules (used to be
16K), and makes it easier to use LoadedModules w/o causing a memory
leak: ListOfModules owns the modules, and makes sure to properly clean
them in destructor.

Remove filtering functionality that is only needed in one place (LSan).

Reviewers: aizatsky

Subscribers: llvm-commits, kcc

Differential Revision: http://reviews.llvm.org/D17470

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@261554 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 16 deletions

diff --git a/lib/lsan/lsan_common_linux.cc b/lib/lsan/lsan_common_linux.cc
index 09f1502c6..1f5430395 100644
--- a/lib/lsan/lsan_common_linux.cc
+++ b/lib/lsan/lsan_common_linux.cc
@@ -26,9 +26,8 @@
 namespace __lsan {
 
 static const char kLinkerName[] = "ld";
-// We request 2 modules matching "ld", so we can print a warning if there's more
-// than one match. But only the first one is actually used.
-static char linker_placeholder[2 * sizeof(LoadedModule)] ALIGNED(64);
+
+static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64);
 static LoadedModule *linker = nullptr;
 
 static bool IsLinker(const char* full_name) {
@@ -36,20 +35,24 @@ static bool IsLinker(const char* full_name) {
 }
 
 void InitializePlatformSpecificModules() {
-  internal_memset(linker_placeholder, 0, sizeof(linker_placeholder));
-  uptr num_matches = GetListOfModules(
-      reinterpret_cast<LoadedModule *>(linker_placeholder), 2, IsLinker);
-  if (num_matches == 1) {
-    linker = reinterpret_cast<LoadedModule *>(linker_placeholder);
-    return;
+  ListOfModules modules;
+  modules.init();
+  for (LoadedModule &module : modules) {
+    if (!IsLinker(module.full_name())) continue;
+    if (linker == nullptr) {
+      linker = reinterpret_cast<LoadedModule *>(linker_placeholder);
+      *linker = module;
+      module = LoadedModule();
+    } else {
+      VReport(1, "LeakSanitizer: Multiple modules match \"%s\". "
+              "TLS will not be handled correctly.\n", kLinkerName);
+      linker->clear();
+      linker = nullptr;
+      return;
+    }
   }
-  if (num_matches == 0)
-    VReport(1, "LeakSanitizer: Dynamic linker not found. "
-            "TLS will not be handled correctly.\n");
-  else if (num_matches > 1)
-    VReport(1, "LeakSanitizer: Multiple modules match \"%s\". "
-            "TLS will not be handled correctly.\n", kLinkerName);
-  linker = nullptr;
+  VReport(1, "LeakSanitizer: Dynamic linker not found. "
+             "TLS will not be handled correctly.\n");
 }
 
 static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size,