[NFC][AssemblyWriter] Allow AssemblyWriter::printBasicBlock() to print blocks that...

Remove the assert in AssemblyWriter::printBasicBlock() and
in BasicBlock::isEntryBlock() that require blocks to have parents.
Instead, have BasicBlock::isEntryBlock() return false for unattached
blocks. This allows us to call these functions for blocks that are
not yet added to a module which is a useful debugging capability.

Committing for xiaoqing_wu

https://reviews.llvm.org/D106127k

diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index 5adc24e..69e2d85 100644 (file)
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -3846,8 +3846,7 @@ void AssemblyWriter::printArgument(const Argument *Arg, AttributeSet Attrs) {
 
 /// printBasicBlock - This member is called for each basic block in a method.
 void AssemblyWriter::printBasicBlock(const BasicBlock *BB) {
-  assert(BB && BB->getParent() && "block without parent!");
-  bool IsEntryBlock = BB->isEntryBlock();
+  bool IsEntryBlock = BB->getParent() && BB->isEntryBlock();
   if (BB->hasName()) {              // Print out the label if it exists...
     Out << "\n";
     PrintLLVMName(Out, BB->getName(), LabelPrefix);