Index: docs/LangRef.rst =================================================================== --- docs/LangRef.rst +++ docs/LangRef.rst @@ -1468,6 +1468,19 @@ This attribute by itself does not imply restrictions on inter-procedural optimizations. All of the semantic effects the patching may have to be separately conveyed via the linkage type. +``"probe-stack"`` + This attribute indicates that the function will trigger a guard region + in the end of the stack. It ensures that accesses to the stack must be + no further apart than the size of the guard region to a previous + access of the stack. It takes one required string value, the name of + the stack probing function that will be called. + + If a function that has a ``"probe-stack"`` attribute is inlined into + a function with another ``"probe-stack"`` attribute, the resulting + function has the ``"probe-stack"`` attribute of the caller. If a + function that has a ``"probe-stack"`` attribute is inlined into a + function that has no ``"probe-stack"`` attribute at all, the resulting + function has the ``"probe-stack"`` attribute of the callee. ``readnone`` On a function, this attribute indicates that the function computes its result (or decides to unwind an exception) based strictly on its arguments, Index: include/llvm/IR/Attributes.td =================================================================== --- include/llvm/IR/Attributes.td +++ include/llvm/IR/Attributes.td @@ -214,3 +214,4 @@ def : MergeRule<"setOR">; def : MergeRule<"setOR">; def : MergeRule<"adjustCallerSSPLevel">; +def : MergeRule<"adjustCallerStackProbes">; Index: lib/IR/Attributes.cpp =================================================================== --- lib/IR/Attributes.cpp +++ lib/IR/Attributes.cpp @@ -1638,6 +1638,13 @@ Caller.addFnAttr(Attribute::StackProtect); } +/// \brief If the inlined function required stack probes, then ensure that +/// the calling function has those too. +static void adjustCallerStackProbes(Function &Caller, const Function &Callee) { + if (!Caller.hasFnAttribute("probe-stack") && Callee.hasFnAttribute("probe-stack")) + Caller.addFnAttr("probe-stack", Callee.getFnAttribute("probe-stack").getValueAsString()); +} + #define GET_ATTR_COMPAT_FUNC #include "AttributesCompatFunc.inc" Index: test/Transforms/Inline/inline-probe-stack.ll =================================================================== --- /dev/null +++ test/Transforms/Inline/inline-probe-stack.ll @@ -0,0 +1,20 @@ +; RUN: opt %s -inline -S | FileCheck %s + +define internal void @inner() "probe-stack"="__probestackinner" { + ret void +} + +define void @outerNoAttribute() { + call void @inner() + ret void +} + +define void @outerConflictingAttribute() "probe-stack"="__probestackouter" { + call void @inner() + ret void +} + +; CHECK: define void @outerNoAttribute() #0 +; CHECK: define void @outerConflictingAttribute() #1 +; CHECK: attributes #0 = { "probe-stack"="__probestackinner" } +; CHECK: attributes #1 = { "probe-stack"="__probestackouter" }