[IR] Support constructing dead_on_return without an argument

[maurer]

After #171712, dead_on_return takes an optional argument indicating the number of bytes known dead. The existing clang callsite uses the attribute builder interface directly which supports the optional argument through DeadOnReturnInfo. However, users constructing the Attribute directly (e.g. rustc) were using Attribute::get which will now default to providing a 0 value to the optional argument.

Add the additional method Attribute::getWithDeadOnReturnInfo to allow users which produce explicit Attribute values to continue to indicate dead_on_return without an argument.

[maurer]

cc @nikic - you just saw rust-lang/rust#151469 which inspired this.

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[llvmbot]

@llvm/pr-subscribers-llvm-ir

Author: Matthew Maurer (maurer)

Changes

After #171712, dead_on_return takes an optional argument indicating the number of bytes known dead. The existing clang callsite uses the attribute builder interface directly which supports the optional argument through DeadOnReturnInfo. However, users constructing the Attribute directly (e.g. rustc) were using Attribute::get which will now default to providing a 0 value to the optional argument.

Add the additional method Attribute::getWithDeadOnReturnInfo to allow users which produce explicit Attribute values to continue to indicate dead_on_return without an argument.

---

Full diff: https://github.com/llvm/llvm-project/pull/177272.diff

2 Files Affected:

• (modified) llvm/include/llvm/IR/Attributes.h (+2)
• (modified) llvm/lib/IR/Attributes.cpp (+5)

diff --git a/llvm/include/llvm/IR/Attributes.h b/llvm/include/llvm/IR/Attributes.h
index ec451f6b08695..534d96d2c46e5 100644
--- a/llvm/include/llvm/IR/Attributes.h
+++ b/llvm/include/llvm/IR/Attributes.h
@@ -212,6 +212,8 @@ class Attribute {
                                                  MemoryEffects ME);
   LLVM_ABI static Attribute getWithNoFPClass(LLVMContext &Context,
                                              FPClassTest Mask);
+  LLVM_ABI static Attribute getWithDeadOnReturnInfo(LLVMContext &Context,
+                                                    DeadOnReturnInfo DI);
   LLVM_ABI static Attribute getWithCaptureInfo(LLVMContext &Context,
                                                CaptureInfo CI);
 
diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index f156202ce6775..ccf0248c3dabc 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -310,6 +310,11 @@ Attribute Attribute::getWithVScaleRangeArgs(LLVMContext &Context,
   return get(Context, VScaleRange, packVScaleRangeArgs(MinValue, MaxValue));
 }
 
+Attribute Attribute::getWithDeadOnReturnInfo(LLVMContext &Context,
+                                             DeadOnReturnInfo DI) {
+  return get(Context, DeadOnReturn, DI.toIntValue());
+}
+
 Attribute::AttrKind Attribute::getAttrKindFromName(StringRef AttrName) {
   return StringSwitch<Attribute::AttrKind>(AttrName)
 #define GET_ATTR_NAMES

[boomanaiden154]

LGTM.

[boomanaiden154]

@maurer You need to configure your Github account to use your actual email address for landing commits. Right now it defaults to the Github noreply email.

[maurer]

Email should be valid now.

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