[llvm][clang][mlir] Add checks for the return values from Target::createXXX to prevent protential null deref
All these potential null pointer dereferences are reported by my static analyzer for null smart pointer dereferences, which has a different implementation from `alpha.cplusplus.SmartPtr`.
The checked pointers in this patch are initialized by Target::createXXX functions. When the creator function pointer is not correctly set, a null pointer will be returned, or the creator function may originally return a null pointer.
Some of them may not make sense as they may be checked before entering the function, but I fixed them all in this patch. I submit this fix because 1) similar checks are found in some other places in the LLVM codebase for the same return value of the function; and, 2) some of the pointers are dereferenced before they are checked, which may definitely trigger a null pointer dereference if the return value is nullptr.
Reviewed By: tejohnson, MaskRay, jpienaar
Differential Revision: https://reviews.llvm.org/D91410
GitOrigin-RevId: 1756d67934bb5fe3b12bdb5fa55d61f61bd70bc5
diff --git a/tools/llvm-ml/llvm-ml.cpp b/tools/llvm-ml/llvm-ml.cpp
index d01c66e..d1ea81c 100644
--- a/tools/llvm-ml/llvm-ml.cpp
+++ b/tools/llvm-ml/llvm-ml.cpp
@@ -315,8 +315,11 @@
std::unique_ptr<MCStreamer> Str;
std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
+ assert(MCII && "Unable to create instruction info!");
+
std::unique_ptr<MCSubtargetInfo> STI(TheTarget->createMCSubtargetInfo(
TripleName, /*CPU=*/"", /*Features=*/""));
+ assert(STI && "Unable to create subtarget info!");
MCInstPrinter *IP = nullptr;
if (FileType == OFT_AssemblyFile) {
