[PATCH] D63668: [Support] Improve zero-size allocation with safe_malloc, etc.

[Xing Xue via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGece53d0ae50a: Improve zero-size allocation with safe_malloc, etc. (authored by xingxue).

Changed prior to commit:
  https://reviews.llvm.org/D63668?vs=206050&id=206457#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D63668/new/

https://reviews.llvm.org/D63668

Files:
  llvm/include/llvm/Support/MemAlloc.h


Index: llvm/include/llvm/Support/MemAlloc.h
===================================================================
--- llvm/include/llvm/Support/MemAlloc.h
+++ llvm/include/llvm/Support/MemAlloc.h
@@ -24,23 +24,41 @@
 
 LLVM_ATTRIBUTE_RETURNS_NONNULL inline void *safe_malloc(size_t Sz) {
   void *Result = std::malloc(Sz);
-  if (Result == nullptr)
+  if (Result == nullptr) {
+    // It is implementation-defined whether allocation occurs if the space
+    // requested is zero (ISO/IEC 9899:2018 7.22.3). Retry, requesting
+    // non-zero, if the space requested was zero.
+    if (Sz == 0)
+      return safe_malloc(1);
     report_bad_alloc_error("Allocation failed");
+  }
   return Result;
 }
 
 LLVM_ATTRIBUTE_RETURNS_NONNULL inline void *safe_calloc(size_t Count,
                                                         size_t Sz) {
   void *Result = std::calloc(Count, Sz);
-  if (Result == nullptr)
+  if (Result == nullptr) {
+    // It is implementation-defined whether allocation occurs if the space
+    // requested is zero (ISO/IEC 9899:2018 7.22.3). Retry, requesting
+    // non-zero, if the space requested was zero.
+    if (Count == 0 || Sz == 0)
+      return safe_malloc(1);
     report_bad_alloc_error("Allocation failed");
+  }
   return Result;
 }
 
 LLVM_ATTRIBUTE_RETURNS_NONNULL inline void *safe_realloc(void *Ptr, size_t Sz) {
   void *Result = std::realloc(Ptr, Sz);
-  if (Result == nullptr)
+  if (Result == nullptr) {
+    // It is implementation-defined whether allocation occurs if the space
+    // requested is zero (ISO/IEC 9899:2018 7.22.3). Retry, requesting
+    // non-zero, if the space requested was zero.
+    if (Sz == 0)
+      return safe_malloc(1);
     report_bad_alloc_error("Allocation failed");
+  }
   return Result;
 }
 


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