[Scudo] ensurePageMapAllocated addressing TODO

[devnexen]

Summary

• reporting issue if PageMap is not allocated

[Chia-hungDuan]

We don't want to abort the process here, it's a soft failure. In addition, when page map allocation fails, it sometimes indicates an OOM on pages, i.e., we may not be able to allocate a single page for ScopedErrorReport. Even though it has local storage, but that means we may crash in the middle of reporting.

The ideal way of doing this is having a reserved space and do it there. This also includes some refactors in the ScopedString/Vector, .etc.

compiler-rt/lib/scudo/standalone/release.h

 //===-- release.h -----------------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SCUDO_RELEASE_H_
 #define SCUDO_RELEASE_H_
 
 #include "common.h"
 #include "list.h"
 #include "mem_map.h"
 #include "mutex.h"
+#include "report.h"
 #include "thread_annotations.h"
 
 namespace scudo {
 
 template <typename MemMapT> class RegionReleaseRecorder {
 public:
   RegionReleaseRecorder(MemMapT *RegionMemMap, uptr Base, uptr Offset = 0)
       : RegionMemMap(RegionMemMap), Base(Base), Offset(Offset) {}
struct PageReleaseContext {
   bool hasBlockMarked() const {
     return PageMap.isAllocated();
   }
 
   bool ensurePageMapAllocated() {
     if (PageMap.isAllocated())
       return true;
     PageMap.reset(NumberOfRegions, PagesCount, FullPagesBlockCountMax);
-    // TODO: Log some message when we fail on PageMap allocation.
+    if (!PageMap.isAllocated())
+        reportPageError(PageMap.getBufferSize());
     return PageMap.isAllocated();
   }
 
   // Mark all the blocks in the given range [From, to). Instead of visiting all
   // the blocks, we will just mark the page as all counted. Note the `From` and
   // `To` has to be page aligned but with one exception, if `To` is equal to the
   // RegionSize, it's not necessary to be aligned with page size.
   bool markRangeAsAllCounted(uptr From, uptr To, uptr Base,

compiler-rt/lib/scudo/standalone/report.h

enum class AllocatorAction : u8 {
   Reallocating,
   Sizing,
 };
 void NORETURN reportInvalidChunkState(AllocatorAction Action, void *Ptr);
 void NORETURN reportMisalignedPointer(AllocatorAction Action, void *Ptr);
 void NORETURN reportDeallocTypeMismatch(AllocatorAction Action, void *Ptr,
                                         u8 TypeA, u8 TypeB);
 void NORETURN reportDeleteSizeMismatch(void *Ptr, uptr Size, uptr ExpectedSize);
+void NORETURN reportPageError(uptr Size);
 
 // C wrappers errors.
 void NORETURN reportAlignmentNotPowerOfTwo(uptr Alignment);
 void NORETURN reportInvalidPosixMemalignAlignment(uptr Alignment);
 void NORETURN reportCallocOverflow(uptr Count, uptr Size);
 void NORETURN reportPvallocOverflow(uptr Size);
 void NORETURN reportInvalidAlignedAllocAlignment(uptr Size, uptr Alignment);
 
 } // namespace scudo
 
 #endif // SCUDO_REPORT_H_

compiler-rt/lib/scudo/standalone/report.cpp

 void NORETURN reportDeleteSizeMismatch(void *Ptr, uptr Size,
                                        uptr ExpectedSize) {
   ScopedErrorReport Report;
   Report.append(
       "invalid sized delete when deallocating address %p (%zu vs %zu)\n", Ptr,
       Size, ExpectedSize);
 }
 
+void NORETURN reportPageError(uptr Size) {
+  ScopedErrorReport Report;
+  Report.append("PageMap allocation failed (BufferSize %lu)",
+                Size);
+}
+
 void NORETURN reportAlignmentNotPowerOfTwo(uptr Alignment) {
   ScopedErrorReport Report;
   Report.append(
       "invalid allocation alignment: %zu, alignment must be a power of two\n",
       Alignment);
 }
 
 void NORETURN reportCallocOverflow(uptr Count, uptr Size) {