[llvm] 03b9f0a - Ignore "no-frame-pointer-elim" and "no-frame-pointer-elim-non-leaf" in favor of "frame-pointer"
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Dec 30 09:48:05 PST 2019
Author: Fangrui Song
Date: 2019-12-30T09:46:19-08:00
New Revision: 03b9f0a5e19aa68fb0a82d80e409333db7ee511c
URL: https://github.com/llvm/llvm-project/commit/03b9f0a5e19aa68fb0a82d80e409333db7ee511c
DIFF: https://github.com/llvm/llvm-project/commit/03b9f0a5e19aa68fb0a82d80e409333db7ee511c.diff
LOG: 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
Added:
llvm/test/Bitcode/upgrade-frame-pointer.ll
Modified:
llvm/docs/ReleaseNotes.rst
llvm/include/llvm/IR/AutoUpgrade.h
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
llvm/lib/CodeGen/TargetOptionsImpl.cpp
llvm/lib/IR/AutoUpgrade.cpp
Removed:
################################################################################
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 1b25a3fc128d..96331a76f266 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+ ``no-frame-pointer-elim-non-leaf`` have been replaced by ``frame-pointer``,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 66f38e5b55d1..42f50cc991de 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 3a56c1aa93bf..33464412edc5 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 039748d817ca..d794a261ecb2 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 d73e511382e7..83bf052eb084 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 000000000000..5251db9ec2db
--- /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" }
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