Skip to content

[DataLayout] Add isNullPointerAllZeroes #165314

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: main
Choose a base branch
from
Open

[DataLayout] Add isNullPointerAllZeroes #165314

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1721831
[DataLayout] Add isNullPointerAllZeroes
ro-i Oct 27, 2025
9113b53
move to getNullPointerValue
ro-i Oct 27, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 10 additions & 0 deletions llvm/include/llvm/IR/DataLayout.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -398,6 +398,16 @@ class DataLayout {
PS.HasExternalState;
}

/// Return the bit value of the null pointer for the given address space.
std::optional<APInt> getNullPointerValue(unsigned AS) const {
// Address space zero is currently defined to always have an all-zero null
// pointer representation, the others are target-specific and will require a
// data layout property (work-in-progress).
if (AS == 0)
return APInt::getZero(getPointerSizeInBits(AS));
return std::nullopt;
}

/// Returns whether this address space has an "unstable" pointer
/// representation. The bitwise pattern of such pointers is allowed to change
/// in a target-specific way. For example, this could be used for copying
Expand Down
9 changes: 9 additions & 0 deletions llvm/unittests/IR/DataLayoutTest.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -700,6 +700,15 @@ TEST(DataLayout, NonIntegralHelpers) {
}
}

TEST(DataLayoutTest, GetNullPointerValue) {
EXPECT_EQ(DataLayout("").getNullPointerValue(0), APInt::getZero(64));
EXPECT_EQ(DataLayout("").getNullPointerValue(1), std::nullopt);
EXPECT_EQ(DataLayout("p:32:32").getNullPointerValue(0), APInt::getZero(32));
EXPECT_EQ(DataLayout("p:32:32").getNullPointerValue(1), std::nullopt);
EXPECT_EQ(DataLayout("p:64:64").getNullPointerValue(0), APInt::getZero(64));
EXPECT_EQ(DataLayout("p:64:64").getNullPointerValue(1), std::nullopt);
}

TEST(DataLayoutTest, CopyAssignmentInvalidatesStructLayout) {
DataLayout DL1 = cantFail(DataLayout::parse("p:32:32"));
DataLayout DL2 = cantFail(DataLayout::parse("p:64:64"));
Expand Down
Loading