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author | Dan Gohman <gohman@apple.com> | 2010-08-30 21:18:41 +0000 |
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committer | Dan Gohman <gohman@apple.com> | 2010-08-30 21:18:41 +0000 |
commit | 56b092e4cd2679d5d2dc892c722fa912e0dccbf9 (patch) | |
tree | 0edb9873a489b5f89fb99478b7d87d40f5423ddd /lib/VMCore | |
parent | 973a074345add36c046c0f0bfea0156a532ab479 (diff) | |
download | llvm-56b092e4cd2679d5d2dc892c722fa912e0dccbf9.tar.gz llvm-56b092e4cd2679d5d2dc892c722fa912e0dccbf9.tar.bz2 llvm-56b092e4cd2679d5d2dc892c722fa912e0dccbf9.tar.xz |
Add comments explaining why it's not necessary to include the
is-function-local flag in metadata uniquing bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112528 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/VMCore')
-rw-r--r-- | lib/VMCore/Metadata.cpp | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/VMCore/Metadata.cpp b/lib/VMCore/Metadata.cpp index 17e0bc28da..b9f97dbf60 100644 --- a/lib/VMCore/Metadata.cpp +++ b/lib/VMCore/Metadata.cpp @@ -190,6 +190,8 @@ MDNode *MDNode::getMDNode(LLVMContext &Context, Value *const *Vals, // Add all the operand pointers. Note that we don't have to add the // isFunctionLocal bit because that's implied by the operands. + // Note that if the operands are later nulled out, the node will be + // removed from the uniquing map. FoldingSetNodeID ID; for (unsigned i = 0; i != NumVals; ++i) ID.AddPointer(Vals[i]); @@ -276,6 +278,8 @@ Value *MDNode::getOperand(unsigned i) const { void MDNode::Profile(FoldingSetNodeID &ID) const { // Add all the operand pointers. Note that we don't have to add the // isFunctionLocal bit because that's implied by the operands. + // Note that if the operands are later nulled out, the node will be + // removed from the uniquing map. for (unsigned i = 0, e = getNumOperands(); i != e; ++i) ID.AddPointer(getOperand(i)); } @@ -326,7 +330,8 @@ void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) { // If we are dropping an argument to null, we choose to not unique the MDNode // anymore. This commonly occurs during destruction, and uniquing these - // brings little reuse. + // brings little reuse. Also, this means we don't need to include + // isFunctionLocal bits in FoldingSetNodeIDs for MDNodes. if (To == 0) { setIsNotUniqued(); return; |