[PATCH] D13627: [JIT] TrivialMemoryManager: Fail if we can't allocate memory

[Davide Italiano via llvm-commits]

davide created this revision.
davide added a reviewer: lhames.
davide added a subscriber: llvm-commits.

TrivialMemoryManager currently doesn't check the return type of AllocateRWX -- and returns a 'null' MemoryBlock to its caller.
I would like to change the behavior, and check for errors inside the memory manager, so that If AllocateRWX fails, we can get an human readable error message that explains why the allocation failed, rather than printing a generic failure message. Also, if we check for memory allocation failures in the MemoryManager, we can guarantee the following invariant: if the memory manager returns, the buffer returned is valid. Therefore the clients can convert error handling into asserts.
Please let me know what you think.

http://reviews.llvm.org/D13627

Files:
  tools/llvm-rtdyld/llvm-rtdyld.cpp

Index: tools/llvm-rtdyld/llvm-rtdyld.cpp
===================================================================
--- tools/llvm-rtdyld/llvm-rtdyld.cpp
+++ tools/llvm-rtdyld/llvm-rtdyld.cpp
@@ -181,7 +181,10 @@
                                                    unsigned Alignment,
                                                    unsigned SectionID,
                                                    StringRef SectionName) {
-  sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, nullptr);
+  std::string Err;
+  sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, &Err);
+  if (!MB.base())
+    report_fatal_error("MemoryManager allocation failed: " + Err);
   FunctionMemory.push_back(MB);
   return (uint8_t*)MB.base();
 }
@@ -191,7 +194,10 @@
                                                    unsigned SectionID,
                                                    StringRef SectionName,
                                                    bool IsReadOnly) {
-  sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, nullptr);
+  std::string Err;
+  sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, &Err);
+  if (!MB.base())
+    report_fatal_error("MemoryManager allocation failed: " + Err);
   DataMemory.push_back(MB);
   return (uint8_t*)MB.base();
 }


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