1 files changed, 270 insertions, 0 deletions
diff --git a/lib/esan/esan.cpp b/lib/esan/esan.cpp
new file mode 100644
index 000000000000..2fb77894d4fb
--- /dev/null
+++ b/lib/esan/esan.cpp
@@ -0,0 +1,270 @@
+//===-- esan.cpp ----------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of EfficiencySanitizer, a family of performance tuners.
+//
+// Main file (entry points) for the Esan run-time.
+//===----------------------------------------------------------------------===//
+
+#include "esan.h"
+#include "esan_flags.h"
+#include "esan_interface_internal.h"
+#include "esan_shadow.h"
+#include "cache_frag.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flag_parser.h"
+#include "sanitizer_common/sanitizer_flags.h"
+#include "working_set.h"
+
+// See comment below.
+extern "C" {
+extern void __cxa_atexit(void (*function)(void));
+}
+
+namespace __esan {
+
+bool EsanIsInitialized;
+bool EsanDuringInit;
+ShadowMapping Mapping;
+
+// Different tools use different scales within the same shadow mapping scheme.
+// The scale used here must match that used by the compiler instrumentation.
+// This array is indexed by the ToolType enum.
+static const uptr ShadowScale[] = {
+  0, // ESAN_None.
+  2, // ESAN_CacheFrag: 4B:1B, so 4 to 1 == >>2.
+  6, // ESAN_WorkingSet: 64B:1B, so 64 to 1 == >>6.
+};
+
+// We are combining multiple performance tuning tools under the umbrella of
+// one EfficiencySanitizer super-tool.  Most of our tools have very similar
+// memory access instrumentation, shadow memory mapping, libc interception,
+// etc., and there is typically more shared code than distinct code.
+//
+// We are not willing to dispatch on tool dynamically in our fastpath
+// instrumentation: thus, which tool to use is a static option selected
+// at compile time and passed to __esan_init().
+//
+// We are willing to pay the overhead of tool dispatch in the slowpath to more
+// easily share code.  We expect to only come here rarely.
+// If this becomes a performance hit, we can add separate interface
+// routines for each subtool (e.g., __esan_cache_frag_aligned_load_4).
+// But for libc interceptors, we'll have to do one of the following:
+// A) Add multiple-include support to sanitizer_common_interceptors.inc,
+//    instantiate it separately for each tool, and call the selected
+//    tool's intercept setup code.
+// B) Build separate static runtime libraries, one for each tool.
+// C) Completely split the tools into separate sanitizers.
+
+void processRangeAccess(uptr PC, uptr Addr, int Size, bool IsWrite) {
+  VPrintf(3, "in esan::%s %p: %c %p %d\n", __FUNCTION__, PC,
+          IsWrite ? 'w' : 'r', Addr, Size);
+  if (__esan_which_tool == ESAN_CacheFrag) {
+    // TODO(bruening): add shadow mapping and update shadow bits here.
+    // We'll move this to cache_frag.cpp once we have something.
+  } else if (__esan_which_tool == ESAN_WorkingSet) {
+    processRangeAccessWorkingSet(PC, Addr, Size, IsWrite);
+  }
+}
+
+bool processSignal(int SigNum, void (*Handler)(int), void (**Result)(int)) {
+  if (__esan_which_tool == ESAN_WorkingSet)
+    return processWorkingSetSignal(SigNum, Handler, Result);
+  return true;
+}
+
+bool processSigaction(int SigNum, const void *Act, void *OldAct) {
+  if (__esan_which_tool == ESAN_WorkingSet)
+    return processWorkingSetSigaction(SigNum, Act, OldAct);
+  return true;
+}
+
+bool processSigprocmask(int How, void *Set, void *OldSet) {
+  if (__esan_which_tool == ESAN_WorkingSet)
+    return processWorkingSetSigprocmask(How, Set, OldSet);
+  return true;
+}
+
+#if SANITIZER_DEBUG
+static bool verifyShadowScheme() {
+  // Sanity checks for our shadow mapping scheme.
+  uptr AppStart, AppEnd;
+  if (Verbosity() >= 3) {
+    for (int i = 0; getAppRegion(i, &AppStart, &AppEnd); ++i) {
+      VPrintf(3, "App #%d: [%zx-%zx) (%zuGB)\n", i, AppStart, AppEnd,
+              (AppEnd - AppStart) >> 30);
+    }
+  }
+  for (int Scale = 0; Scale < 8; ++Scale) {
+    Mapping.initialize(Scale);
+    if (Verbosity() >= 3) {
+      VPrintf(3, "\nChecking scale %d\n", Scale);
+      uptr ShadowStart, ShadowEnd;
+      for (int i = 0; getShadowRegion(i, &ShadowStart, &ShadowEnd); ++i) {
+        VPrintf(3, "Shadow #%d: [%zx-%zx) (%zuGB)\n", i, ShadowStart,
+                ShadowEnd, (ShadowEnd - ShadowStart) >> 30);
+      }
+      for (int i = 0; getShadowRegion(i, &ShadowStart, &ShadowEnd); ++i) {
+        VPrintf(3, "Shadow(Shadow) #%d: [%zx-%zx)\n", i,
+                appToShadow(ShadowStart), appToShadow(ShadowEnd - 1)+1);
+      }
+    }
+    for (int i = 0; getAppRegion(i, &AppStart, &AppEnd); ++i) {
+      DCHECK(isAppMem(AppStart));
+      DCHECK(!isAppMem(AppStart - 1));
+      DCHECK(isAppMem(AppEnd - 1));
+      DCHECK(!isAppMem(AppEnd));
+      DCHECK(!isShadowMem(AppStart));
+      DCHECK(!isShadowMem(AppEnd - 1));
+      DCHECK(isShadowMem(appToShadow(AppStart)));
+      DCHECK(isShadowMem(appToShadow(AppEnd - 1)));
+      // Double-shadow checks.
+      DCHECK(!isShadowMem(appToShadow(appToShadow(AppStart))));
+      DCHECK(!isShadowMem(appToShadow(appToShadow(AppEnd - 1))));
+    }
+    // Ensure no shadow regions overlap each other.
+    uptr ShadowAStart, ShadowBStart, ShadowAEnd, ShadowBEnd;
+    for (int i = 0; getShadowRegion(i, &ShadowAStart, &ShadowAEnd); ++i) {
+      for (int j = 0; getShadowRegion(j, &ShadowBStart, &ShadowBEnd); ++j) {
+        DCHECK(i == j || ShadowAStart >= ShadowBEnd ||
+               ShadowAEnd <= ShadowBStart);
+      }
+    }
+  }
+  return true;
+}
+#endif
+
+static void initializeShadow() {
+  verifyAddressSpace();
+
+  DCHECK(verifyShadowScheme());
+
+  Mapping.initialize(ShadowScale[__esan_which_tool]);
+
+  VPrintf(1, "Shadow scale=%d offset=%p\n", Mapping.Scale, Mapping.Offset);
+
+  uptr ShadowStart, ShadowEnd;
+  for (int i = 0; getShadowRegion(i, &ShadowStart, &ShadowEnd); ++i) {
+    VPrintf(1, "Shadow #%d: [%zx-%zx) (%zuGB)\n", i, ShadowStart, ShadowEnd,
+            (ShadowEnd - ShadowStart) >> 30);
+
+    uptr Map;
+    if (__esan_which_tool == ESAN_WorkingSet) {
+      // We want to identify all shadow pages that are touched so we start
+      // out inaccessible.
+      Map = (uptr)MmapFixedNoAccess(ShadowStart, ShadowEnd- ShadowStart,
+                                    "shadow");
+    } else {
+      Map = (uptr)MmapFixedNoReserve(ShadowStart, ShadowEnd - ShadowStart,
+                                     "shadow");
+    }
+    if (Map != ShadowStart) {
+      Printf("FATAL: EfficiencySanitizer failed to map its shadow memory.\n");
+      Die();
+    }
+
+    if (common_flags()->no_huge_pages_for_shadow)
+      NoHugePagesInRegion(ShadowStart, ShadowEnd - ShadowStart);
+    if (common_flags()->use_madv_dontdump)
+      DontDumpShadowMemory(ShadowStart, ShadowEnd - ShadowStart);
+
+    // TODO: Call MmapNoAccess() on in-between regions.
+  }
+}
+
+void initializeLibrary(ToolType Tool) {
+  // We assume there is only one thread during init, but we need to
+  // guard against double-init when we're (re-)called from an
+  // early interceptor.
+  if (EsanIsInitialized || EsanDuringInit)
+    return;
+  EsanDuringInit = true;
+  CHECK(Tool == __esan_which_tool);
+  SanitizerToolName = "EfficiencySanitizer";
+  CacheBinaryName();
+  initializeFlags();
+
+  // Intercepting libc _exit or exit via COMMON_INTERCEPTOR_ON_EXIT only
+  // finalizes on an explicit exit call by the app.  To handle a normal
+  // exit we register an atexit handler.
+  ::__cxa_atexit((void (*)())finalizeLibrary);
+
+  VPrintf(1, "in esan::%s\n", __FUNCTION__);
+  if (__esan_which_tool <= ESAN_None || __esan_which_tool >= ESAN_Max) {
+    Printf("ERROR: unknown tool %d requested\n", __esan_which_tool);
+    Die();
+  }
+
+  initializeShadow();
+  if (__esan_which_tool == ESAN_WorkingSet)
+    initializeShadowWorkingSet();
+
+  initializeInterceptors();
+
+  if (__esan_which_tool == ESAN_CacheFrag) {
+    initializeCacheFrag();
+  } else if (__esan_which_tool == ESAN_WorkingSet) {
+    initializeWorkingSet();
+  }
+
+  EsanIsInitialized = true;
+  EsanDuringInit = false;
+}
+
+int finalizeLibrary() {
+  VPrintf(1, "in esan::%s\n", __FUNCTION__);
+  if (__esan_which_tool == ESAN_CacheFrag) {
+    return finalizeCacheFrag();
+  } else if (__esan_which_tool == ESAN_WorkingSet) {
+    return finalizeWorkingSet();
+  }
+  return 0;
+}
+
+void reportResults() {
+  VPrintf(1, "in esan::%s\n", __FUNCTION__);
+  if (__esan_which_tool == ESAN_CacheFrag) {
+    return reportCacheFrag();
+  } else if (__esan_which_tool == ESAN_WorkingSet) {
+    return reportWorkingSet();
+  }
+}
+
+void processCompilationUnitInit(void *Ptr) {
+  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  if (__esan_which_tool == ESAN_CacheFrag) {
+    DCHECK(Ptr != nullptr);
+    processCacheFragCompilationUnitInit(Ptr);
+  } else {
+    DCHECK(Ptr == nullptr);
+  }
+}
+
+// This is called when the containing module is unloaded.
+// For the main executable module, this is called after finalizeLibrary.
+void processCompilationUnitExit(void *Ptr) {
+  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  if (__esan_which_tool == ESAN_CacheFrag) {
+    DCHECK(Ptr != nullptr);
+    processCacheFragCompilationUnitExit(Ptr);
+  } else {
+    DCHECK(Ptr == nullptr);
+  }
+}
+
+unsigned int getSampleCount() {
+  VPrintf(1, "in esan::%s\n", __FUNCTION__);
+  if (__esan_which_tool == ESAN_WorkingSet) {
+    return getSampleCountWorkingSet();
+  }
+  return 0;
+}
+
+} // namespace __esan