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//===-- 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);
}
}
} // namespace __esan