Split DescribeAddressIfShadow between a function that gets all the information, and one that prints it.

Summary:
Replacement for part of D23518
This is the first patch to start reifying information about errors. It deals only with reifying shadow address-related information.
It will allow us to generate structures with all the relevant information for a given error so a debugger can get to them or they can be included in a core dump.

Reviewers: kcc, samsonov

Subscribers: kubabrecka, llvm-commits

Differential Revision: https://reviews.llvm.org/D23519

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@278718 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 97 insertions, 23 deletions

diff --git a/lib/asan/CMakeLists.txt b/lib/asan/CMakeLists.txt
index b7e41fc70..7325932f0 100644
--- a/lib/asan/CMakeLists.txt
+++ b/lib/asan/CMakeLists.txt
@@ -4,6 +4,7 @@ set(ASAN_SOURCES
   asan_allocator.cc
   asan_activation.cc
   asan_debugging.cc
+  asan_descriptions.cc
   asan_fake_stack.cc
   asan_flags.cc
   asan_globals.cc
diff --git a/lib/asan/asan_debugging.cc b/lib/asan/asan_debugging.cc
index 7c3a8a73b..b7481ffb7 100644
--- a/lib/asan/asan_debugging.cc
+++ b/lib/asan/asan_debugging.cc
@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "asan_allocator.h"
+#include "asan_descriptions.h"
 #include "asan_flags.h"
 #include "asan_internal.h"
 #include "asan_mapping.h"
@@ -65,7 +66,9 @@ void GetInfoForHeapAddress(uptr addr, AddressDescription *descr) {
 }
 
 void AsanLocateAddress(uptr addr, AddressDescription *descr) {
-  if (DescribeAddressIfShadow(addr, descr, /* print */ false)) {
+  ShadowAddressDescription shadow_descr;
+  if (GetShadowAddressInformation(addr, &shadow_descr)) {
+    descr->region_kind = ShadowNames[shadow_descr.kind];
     return;
   }
   if (GetInfoForAddressIfGlobal(addr, descr)) {
diff --git a/lib/asan/asan_descriptions.cc b/lib/asan/asan_descriptions.cc
new file mode 100644
index 000000000..9fc52a4ca
--- /dev/null
+++ b/lib/asan/asan_descriptions.cc
@@ -0,0 +1,54 @@
+//===-- asan_descriptions.cc ------------------------------------*- C++ -*-===//
+//
+//                     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 AddressSanitizer, an address sanity checker.
+//
+// ASan functions for getting information about an address and/or printing it.
+//===----------------------------------------------------------------------===//
+
+#include "asan_descriptions.h"
+#include "asan_mapping.h"
+
+namespace __asan {
+
+// Shadow descriptions
+static bool GetShadowKind(uptr addr, ShadowKind *shadow_kind) {
+  CHECK(!AddrIsInMem(addr));
+  if (AddrIsInShadowGap(addr)) {
+    *shadow_kind = kShadowKindGap;
+  } else if (AddrIsInHighShadow(addr)) {
+    *shadow_kind = kShadowKindHigh;
+  } else if (AddrIsInLowShadow(addr)) {
+    *shadow_kind = kShadowKindLow;
+  } else {
+    CHECK(0 && "Address is not in memory and not in shadow?");
+    return false;
+  }
+  return true;
+}
+
+bool DescribeAddressIfShadow(uptr addr) {
+  ShadowAddressDescription descr;
+  if (!GetShadowAddressInformation(addr, &descr)) return false;
+  Printf("Address %p is located in the %s area.\n", addr,
+         ShadowNames[descr.kind]);
+  return true;
+}
+
+bool GetShadowAddressInformation(uptr addr, ShadowAddressDescription *descr) {
+  if (AddrIsInMem(addr)) return false;
+  ShadowKind shadow_kind;
+  if (!GetShadowKind(addr, &shadow_kind)) return false;
+  if (shadow_kind != kShadowKindGap) descr->shadow_byte = *(u8 *)addr;
+  descr->addr = addr;
+  descr->kind = shadow_kind;
+  return true;
+}
+
+}  // namespace __asan
diff --git a/lib/asan/asan_descriptions.h b/lib/asan/asan_descriptions.h
new file mode 100644
index 000000000..c96fef953
--- /dev/null
+++ b/lib/asan/asan_descriptions.h
@@ -0,0 +1,37 @@
+//===-- asan_descriptions.h -------------------------------------*- C++ -*-===//
+//
+//                     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 AddressSanitizer, an address sanity checker.
+//
+// ASan-private header for asan_descriptions.cc.
+// TODO(filcab): Most struct definitions should move to the interface headers.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_common.h"
+
+namespace __asan {
+
+enum ShadowKind : u8 {
+  kShadowKindLow,
+  kShadowKindGap,
+  kShadowKindHigh,
+};
+static const char *const ShadowNames[] = {"low shadow", "shadow gap",
+                                          "high shadow"};
+
+struct ShadowAddressDescription {
+  uptr addr;
+  ShadowKind kind;
+  u8 shadow_byte;
+};
+
+bool GetShadowAddressInformation(uptr addr, ShadowAddressDescription *descr);
+bool DescribeAddressIfShadow(uptr addr);
+
+}  // namespace __asan
diff --git a/lib/asan/asan_report.cc b/lib/asan/asan_report.cc
index afdd4ea63..7b632ac10 100644
--- a/lib/asan/asan_report.cc
+++ b/lib/asan/asan_report.cc
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "asan_flags.h"
+#include "asan_descriptions.h"
 #include "asan_internal.h"
 #include "asan_mapping.h"
 #include "asan_report.h"
@@ -336,26 +337,6 @@ static bool DescribeAddressIfGlobal(uptr addr, uptr size,
   return true;
 }
 
-bool DescribeAddressIfShadow(uptr addr, AddressDescription *descr, bool print) {
-  if (AddrIsInMem(addr))
-    return false;
-  const char *area_type = nullptr;
-  if (AddrIsInShadowGap(addr)) area_type = "shadow gap";
-  else if (AddrIsInHighShadow(addr)) area_type = "high shadow";
-  else if (AddrIsInLowShadow(addr)) area_type = "low shadow";
-  if (area_type != nullptr) {
-    if (print) {
-      Printf("Address %p is located in the %s area.\n", addr, area_type);
-    } else {
-      CHECK(descr);
-      descr->region_kind = area_type;
-    }
-    return true;
-  }
-  CHECK(0 && "Address is not in memory and not in shadow?");
-  return false;
-}
-
 // Return " (thread_name) " or an empty string if the name is empty.
 const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
                                       uptr buff_len) {
diff --git a/lib/asan/asan_report.h b/lib/asan/asan_report.h
index 03f096581..377bc3d11 100644
--- a/lib/asan/asan_report.h
+++ b/lib/asan/asan_report.h
@@ -41,8 +41,6 @@ bool GetInfoForAddressIfGlobal(uptr addr, AddressDescription *descr);
 // The following functions prints address description depending
 // on the memory type (shadow/heap/stack/global).
 void DescribeHeapAddress(uptr addr, uptr access_size);
-bool DescribeAddressIfShadow(uptr addr, AddressDescription *descr = nullptr,
-                             bool print = true);
 bool ParseFrameDescription(const char *frame_descr,
                            InternalMmapVector<StackVarDescr> *vars);
 bool DescribeAddressIfStack(uptr addr, uptr access_size);