[llvm][AArch64] Autoupgrade function attributes from Module attributes #82742
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…s. (llvm#80640) `sign-return-address` and similar module attributes should be propagated to the function level before modules got merged because module flags may contradict and this information is not recoverable. Generated code will match with the normal linking flow.
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@llvm/pr-subscribers-llvm-ir @llvm/pr-subscribers-lto Author: Dani (DanielKristofKiss) Changes
Full diff: https://github.com/llvm/llvm-project/pull/82742.diff 8 Files Affected:
diff --git a/llvm/include/llvm/IR/AutoUpgrade.h b/llvm/include/llvm/IR/AutoUpgrade.h
index 152f781ffa9b30..c0d96efc54752a 100644
--- a/llvm/include/llvm/IR/AutoUpgrade.h
+++ b/llvm/include/llvm/IR/AutoUpgrade.h
@@ -67,7 +67,8 @@ namespace llvm {
void UpgradeSectionAttributes(Module &M);
/// Correct any IR that is relying on old function attribute behavior.
- void UpgradeFunctionAttributes(Function &F);
+ void UpgradeFunctionAttributes(Function &F,
+ bool ModuleMetadataIsMaterialized = false);
/// If the given TBAA tag uses the scalar TBAA format, create a new node
/// corresponding to the upgrade to the struct-path aware TBAA format.
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index a027d0c21ba0bb..f6facb37c020b2 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -6702,7 +6702,7 @@ Error BitcodeReader::materialize(GlobalValue *GV) {
}
// Look for functions that rely on old function attribute behavior.
- UpgradeFunctionAttributes(*F);
+ UpgradeFunctionAttributes(*F, true);
// Bring in any functions that this function forward-referenced via
// blockaddresses.
diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index b90bbe71ac1896..edff13c796b31e 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -5155,7 +5155,46 @@ struct StrictFPUpgradeVisitor : public InstVisitor<StrictFPUpgradeVisitor> {
};
} // namespace
-void llvm::UpgradeFunctionAttributes(Function &F) {
+// Check if the module attribute is present and not zero.
+static bool isModuleAttributeSet(const Module *M, const StringRef &ModAttr) {
+ const auto *Attr =
+ mdconst::extract_or_null<ConstantInt>(M->getModuleFlag(ModAttr));
+ return Attr && Attr->getZExtValue();
+}
+
+// Copy an attribute from module to the function if exists.
+// First value of the pair is used when the module attribute is not zero
+// the second otherwise.
+static void
+CopyModuleAttributeToFunction(Function &F, StringRef FnAttrName,
+ StringRef ModAttrName,
+ std::pair<StringRef, StringRef> Values) {
+ if (F.hasFnAttribute(FnAttrName))
+ return;
+ F.addFnAttr(FnAttrName, isModuleAttributeSet(F.getParent(), ModAttrName)
+ ? Values.first
+ : Values.second);
+}
+
+// Copy a boolean attribute from module to the function if exists.
+// Module attribute treated false if zero otherwise true.
+static void CopyModuleAttributeToFunction(Function &F, StringRef AttrName) {
+ CopyModuleAttributeToFunction(
+ F, AttrName, AttrName,
+ std::make_pair<StringRef, StringRef>("true", "false"));
+}
+
+// Copy an attribute from module to the function if exists.
+// First value of the pair is used when the module attribute is not zero
+// the second otherwise.
+static void
+CopyModuleAttributeToFunction(Function &F, StringRef AttrName,
+ std::pair<StringRef, StringRef> Values) {
+ CopyModuleAttributeToFunction(F, AttrName, AttrName, Values);
+}
+
+void llvm::UpgradeFunctionAttributes(Function &F,
+ bool ModuleMetadataIsMaterialized) {
// If a function definition doesn't have the strictfp attribute,
// convert any callsite strictfp attributes to nobuiltin.
if (!F.isDeclaration() && !F.hasFnAttribute(Attribute::StrictFP)) {
@@ -5167,6 +5206,37 @@ void llvm::UpgradeFunctionAttributes(Function &F) {
F.removeRetAttrs(AttributeFuncs::typeIncompatible(F.getReturnType()));
for (auto &Arg : F.args())
Arg.removeAttrs(AttributeFuncs::typeIncompatible(Arg.getType()));
+
+ if (!ModuleMetadataIsMaterialized)
+ return;
+ if (F.isDeclaration())
+ return;
+ Module *M = F.getParent();
+ if (!M)
+ return;
+
+ Triple T(M->getTargetTriple());
+ // Convert module level attributes to function level attributes because
+ // after merging modules the attributes might change and would have different
+ // effect on the functions as the original module would have.
+ if (T.isThumb() || T.isARM() || T.isAArch64()) {
+ if (!F.hasFnAttribute("sign-return-address")) {
+ StringRef SignType = "none";
+ if (isModuleAttributeSet(M, "sign-return-address"))
+ SignType = "non-leaf";
+
+ if (isModuleAttributeSet(M, "sign-return-address-all"))
+ SignType = "all";
+
+ F.addFnAttr("sign-return-address", SignType);
+ }
+ CopyModuleAttributeToFunction(F, "branch-target-enforcement");
+ CopyModuleAttributeToFunction(F, "branch-protection-pauth-lr");
+ CopyModuleAttributeToFunction(F, "guarded-control-stack");
+ CopyModuleAttributeToFunction(
+ F, "sign-return-address-key",
+ std::make_pair<StringRef, StringRef>("b_key", "a_key"));
+ }
}
static bool isOldLoopArgument(Metadata *MD) {
diff --git a/llvm/lib/Linker/IRMover.cpp b/llvm/lib/Linker/IRMover.cpp
index 1bd562d1e8ae2b..5542d0e515d3a9 100644
--- a/llvm/lib/Linker/IRMover.cpp
+++ b/llvm/lib/Linker/IRMover.cpp
@@ -1605,6 +1605,10 @@ Error IRLinker::run() {
// Loop over all of the linked values to compute type mappings.
computeTypeMapping();
+ // Update function attributes before copying them to destation module.
+ for (Function &F : SrcM->getFunctionList())
+ UpgradeFunctionAttributes(F, true);
+
std::reverse(Worklist.begin(), Worklist.end());
while (!Worklist.empty()) {
GlobalValue *GV = Worklist.back();
diff --git a/llvm/test/Bitcode/upgrade-arc-runtime-calls.ll b/llvm/test/Bitcode/upgrade-arc-runtime-calls.ll
index 19f25f98953fad..d2edec18d55e59 100644
--- a/llvm/test/Bitcode/upgrade-arc-runtime-calls.ll
+++ b/llvm/test/Bitcode/upgrade-arc-runtime-calls.ll
@@ -55,7 +55,7 @@ unwindBlock:
// Check that auto-upgrader converts function calls to intrinsic calls. Note that
// the auto-upgrader doesn't touch invoke instructions.
-// ARC: define void @testRuntimeCalls(ptr %[[A:.*]], ptr %[[B:.*]], ptr %[[C:.*]], ptr %[[D:.*]], ptr %[[E:.*]]) personality
+// ARC: define void @testRuntimeCalls(ptr %[[A:.*]], ptr %[[B:.*]], ptr %[[C:.*]], ptr %[[D:.*]], ptr %[[E:.*]]) #0 personality
// ARC: %[[V0:.*]] = tail call ptr @llvm.objc.autorelease(ptr %[[A]])
// ARC-NEXT: tail call void @llvm.objc.autoreleasePoolPop(ptr %[[A]])
// ARC-NEXT: %[[V1:.*]] = tail call ptr @llvm.objc.autoreleasePoolPush()
@@ -88,7 +88,7 @@ unwindBlock:
// ARC-NEXT: tail call void @llvm.objc.arc.annotation.bottomup.bbend(ptr %[[B]], ptr %[[C]])
// ARC-NEXT: invoke void @objc_autoreleasePoolPop(ptr %[[A]])
-// NOUPGRADE: define void @testRuntimeCalls(ptr %[[A:.*]], ptr %[[B:.*]], ptr %[[C:.*]], ptr %[[D:.*]], ptr %[[E:.*]]) personality
+// NOUPGRADE: define void @testRuntimeCalls(ptr %[[A:.*]], ptr %[[B:.*]], ptr %[[C:.*]], ptr %[[D:.*]], ptr %[[E:.*]]) #0 personality
// NOUPGRADE: %[[V0:.*]] = tail call ptr @objc_autorelease(ptr %[[A]])
// NOUPGRADE-NEXT: tail call void @objc_autoreleasePoolPop(ptr %[[A]])
// NOUPGRADE-NEXT: %[[V1:.*]] = tail call ptr @objc_autoreleasePoolPush()
diff --git a/llvm/test/LTO/AArch64/link-branch-target-enforcement.ll b/llvm/test/LTO/AArch64/link-branch-target-enforcement.ll
index ccf8cf67ede6dc..74d9c86881d52c 100644
--- a/llvm/test/LTO/AArch64/link-branch-target-enforcement.ll
+++ b/llvm/test/LTO/AArch64/link-branch-target-enforcement.ll
@@ -32,6 +32,7 @@ entry:
; CHECK-DUMP: <main>:
; CHECK-DUMP: bl 0x8 <main+0x8>
; CHECK-DUMP: <foo>:
+; CHECK-DUMP: paciasp
; `main` doesn't support BTI while `foo` does, so in the binary
; we should see only PAC which is supported by both.
diff --git a/llvm/test/LTO/AArch64/link-sign-return-address.ll b/llvm/test/LTO/AArch64/link-sign-return-address.ll
new file mode 100644
index 00000000000000..c25857ceed7b40
--- /dev/null
+++ b/llvm/test/LTO/AArch64/link-sign-return-address.ll
@@ -0,0 +1,43 @@
+; Testcase to check that module with different branch-target-enforcement can
+; be mixed.
+;
+; RUN: llvm-as %s -o %t1.bc
+; RUN: llvm-as %p/Inputs/foo.ll -o %t2.bc
+; RUN: llvm-lto -exported-symbol main \
+; RUN: -exported-symbol foo \
+; RUN: -filetype=obj \
+; RUN: %t2.bc %t1.bc \
+; RUN: -o %t1.exe 2>&1
+; RUN: llvm-objdump -d %t1.exe | FileCheck --check-prefix=CHECK-DUMP %s
+; RUN: llvm-readelf -n %t1.exe | FileCheck --allow-empty --check-prefix=CHECK-PROP %s
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+declare i32 @foo();
+
+define i32 @main() {
+entry:
+ %add = call i32 @foo()
+ ret i32 %add
+}
+
+!llvm.module.flags = !{!0, !1, !2, !3 }
+!0 = !{i32 8, !"branch-target-enforcement", i32 0}
+!1 = !{i32 8, !"sign-return-address", i32 0}
+!2 = !{i32 8, !"sign-return-address-all", i32 0}
+!3 = !{i32 8, !"sign-return-address-with-bkey", i32 0}
+
+; CHECK-DUMP: <foo>:
+; CHECK-DUMP: paciasp
+; CHECK-DUMP: mov w0, #0x2a
+; CHECK-DUMP: autiasp
+; CHECK-DUMP: ret
+; CHECK-DUMP: <main>:
+; CHECK-DUMP-NOT: paciasp
+; CHECK-DUMP: str x30,
+; CHECK-DUMP: bl 0x14 <main+0x4>
+
+; `main` doesn't support PAC sign-return-address while `foo` does, so in the binary
+; we should not see anything.
+; CHECK-PROP-NOT: Properties: aarch64 feature: PAC
\ No newline at end of file
diff --git a/llvm/test/Linker/link-arm-and-thumb.ll b/llvm/test/Linker/link-arm-and-thumb.ll
index a90f2128e4430a..37bd8c37f8b5e5 100644
--- a/llvm/test/Linker/link-arm-and-thumb.ll
+++ b/llvm/test/Linker/link-arm-and-thumb.ll
@@ -13,11 +13,12 @@ entry:
ret i32 %add
}
-; CHECK: define i32 @main() {
+; CHECK: define i32 @main() [[MAIN_ATTRS:#[0-9]+]]
; CHECK: define i32 @foo(i32 %a, i32 %b) [[ARM_ATTRS:#[0-9]+]]
; CHECK: define i32 @bar(i32 %a, i32 %b) [[THUMB_ATTRS:#[0-9]+]]
-; CHECK: attributes [[ARM_ATTRS]] = { "target-features"="-thumb-mode" }
-; CHECK: attributes [[THUMB_ATTRS]] = { "target-features"="+thumb-mode" }
+; CHECK: attributes [[MAIN_ATTRS]] = { {{.*}} }
+; CHECK: attributes [[ARM_ATTRS]] = { {{.*}} "target-features"="-thumb-mode" }
+; CHECK: attributes [[THUMB_ATTRS]] = { {{.*}} "target-features"="+thumb-mode" }
; STDERR-NOT: warning: Linking two modules of different target triples:
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nickdesaulniers
requested changes
Feb 26, 2024
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I created #84037 with the relanded version of the patch. |
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sign-return-addressand similar module attributes should be propagated to the function level before modules got merged because module flags may contradict and this information is not recoverable. Generated code will match with the normal linking flow.Backport of (#80640)