From 03b9f0a5e19aa68fb0a82d80e409333db7ee511c Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Tue, 24 Dec 2019 18:12:15 -0800 Subject: [PATCH] Ignore "no-frame-pointer-elim" and "no-frame-pointer-elim-non-leaf" in favor of "frame-pointer" D56351 (included in LLVM 8.0.0) introduced "frame-pointer". All tests which use "no-frame-pointer-elim" or "no-frame-pointer-elim-non-leaf" have been migrated to use "frame-pointer". Implement UpgradeFramePointerAttributes to upgrade the two obsoleted function attributes for bitcode. Their semantics are ignored. Differential Revision: https://reviews.llvm.org/D71863 --- llvm/docs/ReleaseNotes.rst | 5 +++++ llvm/include/llvm/IR/AutoUpgrade.h | 5 +++++ llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 1 + llvm/lib/CodeGen/TargetOptionsImpl.cpp | 14 +------------ llvm/lib/IR/AutoUpgrade.cpp | 20 ++++++++++++++++++ llvm/test/Bitcode/upgrade-frame-pointer.ll | 33 ++++++++++++++++++++++++++++++ 6 files changed, 65 insertions(+), 13 deletions(-) create mode 100644 llvm/test/Bitcode/upgrade-frame-pointer.ll diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst index 1b25a3f..96331a7 100644 --- a/llvm/docs/ReleaseNotes.rst +++ b/llvm/docs/ReleaseNotes.rst @@ -93,6 +93,11 @@ Non-comprehensive list of changes in this release * ``Callbacks`` have been added to ``CommandLine Options``. These can be used to validate of selectively enable other options. +* The function attributes ``no-frame-pointer-elim`` and + ``no-frame-pointer-elim-non-leaf`` have been replaced by ``frame-pointer``, + which has 3 values: ``none``, ``non-leaf``, and ``all``. The values mean what + functions should retain frame pointers. + Changes to the LLVM IR ---------------------- diff --git a/llvm/include/llvm/IR/AutoUpgrade.h b/llvm/include/llvm/IR/AutoUpgrade.h index 66f38e5..42f50cc 100644 --- a/llvm/include/llvm/IR/AutoUpgrade.h +++ b/llvm/include/llvm/IR/AutoUpgrade.h @@ -16,6 +16,7 @@ #include "llvm/ADT/StringRef.h" namespace llvm { + class AttrBuilder; class CallInst; class Constant; class Function; @@ -91,6 +92,10 @@ namespace llvm { /// pointers. std::string UpgradeDataLayoutString(StringRef DL, StringRef Triple); + /// Upgrade function attributes "no-frame-pointer-elim" and + /// "no-frame-pointer-elim-non-leaf" to "frame-pointer". + void UpgradeFramePointerAttributes(AttrBuilder &B); + } // End llvm namespace #endif diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp index 3a56c1a..3346441 100644 --- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp +++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp @@ -1661,6 +1661,7 @@ Error BitcodeReader::parseAttributeGroupBlock() { } } + UpgradeFramePointerAttributes(B); MAttributeGroups[GrpID] = AttributeList::get(Context, Idx, B); break; } diff --git a/llvm/lib/CodeGen/TargetOptionsImpl.cpp b/llvm/lib/CodeGen/TargetOptionsImpl.cpp index 039748d..d794a26 100644 --- a/llvm/lib/CodeGen/TargetOptionsImpl.cpp +++ b/llvm/lib/CodeGen/TargetOptionsImpl.cpp @@ -28,20 +28,8 @@ bool TargetOptions::DisableFramePointerElim(const MachineFunction &MF) const { const Function &F = MF.getFunction(); - // TODO: Remove support for old `fp elim` function attributes after fully - // migrate to use "frame-pointer" - if (!F.hasFnAttribute("frame-pointer")) { - // Check to see if we should eliminate all frame pointers. - if (F.getFnAttribute("no-frame-pointer-elim").getValueAsString() == "true") - return true; - - // Check to see if we should eliminate non-leaf frame pointers. - if (F.hasFnAttribute("no-frame-pointer-elim-non-leaf")) - return MF.getFrameInfo().hasCalls(); - + if (!F.hasFnAttribute("frame-pointer")) return false; - } - StringRef FP = F.getFnAttribute("frame-pointer").getValueAsString(); if (FP == "all") return true; diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp index d73e511..83bf052 100644 --- a/llvm/lib/IR/AutoUpgrade.cpp +++ b/llvm/lib/IR/AutoUpgrade.cpp @@ -4177,3 +4177,23 @@ std::string llvm::UpgradeDataLayoutString(StringRef DL, StringRef TT) { std::string Res = (Groups[1] + AddrSpaces + Groups[3]).toStringRef(Buf).str(); return Res; } + +void llvm::UpgradeFramePointerAttributes(AttrBuilder &B) { + StringRef FramePointer; + if (B.contains("no-frame-pointer-elim")) { + // The value can be "true" or "false". + for (const auto &I : B.td_attrs()) + if (I.first == "no-frame-pointer-elim") + FramePointer = I.second == "true" ? "all" : "none"; + B.removeAttribute("no-frame-pointer-elim"); + } + if (B.contains("no-frame-pointer-elim-non-leaf")) { + // The value is ignored. "no-frame-pointer-elim"="true" takes priority. + if (FramePointer != "all") + FramePointer = "non-leaf"; + B.removeAttribute("no-frame-pointer-elim-non-leaf"); + } + + if (!FramePointer.empty()) + B.addAttribute("frame-pointer", FramePointer); +} diff --git a/llvm/test/Bitcode/upgrade-frame-pointer.ll b/llvm/test/Bitcode/upgrade-frame-pointer.ll new file mode 100644 index 0000000..5251db9 --- /dev/null +++ b/llvm/test/Bitcode/upgrade-frame-pointer.ll @@ -0,0 +1,33 @@ +;; Test that function attributes "no-frame-pointer-elim" ("true" or "false") and +;; "no-frame-pointer-elim-non-leaf" (value is ignored) can be upgraded to +;; "frame-pointer". + +; RUN: llvm-as %s -o - | llvm-dis - | FileCheck %s + +; CHECK: define void @all0() #0 +define void @all0() "no-frame-pointer-elim"="true" { ret void } +; CHECK: define void @all1() #1 +define void @all1() #0 { ret void } + +; CHECK: define void @non_leaf0() #2 +define void @non_leaf0() "no-frame-pointer-elim-non-leaf" { ret void } +; CHECK: define void @non_leaf1() #3 +define void @non_leaf1() #1 { ret void } + +; CHECK: define void @none() #4 +define void @none() "no-frame-pointer-elim"="false" { ret void } + +;; Don't add "frame-pointer" if neither "no-frame-pointer-elim" nor +;; "no-frame-pointer-elim-non-leaf" is present. +; CHECK: define void @no_attr() { +define void @no_attr() { ret void } + +attributes #0 = { readnone "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" } +attributes #1 = { readnone "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf" } + +;; Other attributes (e.g. readnone) are unaffected. +; CHECK: attributes #0 = { "frame-pointer"="all" } +; CHECK: attributes #1 = { readnone "frame-pointer"="all" } +; CHECK: attributes #2 = { "frame-pointer"="non-leaf" } +; CHECK: attributes #3 = { readnone "frame-pointer"="non-leaf" } +; CHECK: attributes #4 = { "frame-pointer"="none" } -- 2.7.4