[PATCH] D149721: EntryExitInstrumenter: skip naked functions
Fangrui Song via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu May 4 09:21:31 PDT 2023
This revision was automatically updated to reflect the committed changes.
Closed by commit rG3460f727eaa3: EntryExitInstrumenter: skip naked functions (authored by MaskRay).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D149721/new/
https://reviews.llvm.org/D149721
Files:
llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
Index: llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
===================================================================
--- llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
+++ llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
@@ -99,6 +99,13 @@
; CHECK: ret
}
+;; naked functions are not instrumented, otherwise the argument registers
+;; and the return address register (if present) would be clobbered.
+define void @naked() naked { entry: ret void }
+; CHECK-LABEL: define void @naked(
+; CHECK-LABEL-NEXT: entry:
+; CHECK-LABEL-NEXT: ret void
+
; The attributes are "consumed" when the instrumentation is inserted.
; CHECK: attributes
; CHECK-NOT: instrument-function
Index: llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
===================================================================
--- llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
+++ llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
@@ -80,6 +80,13 @@
}
static bool runOnFunction(Function &F, bool PostInlining) {
+ // The asm in a naked function may reasonably expect the argument registers
+ // and the return address register (if present) to be live. An inserted
+ // function call will clobber these registers. Simply skip naked functions for
+ // all targets.
+ if (F.hasFnAttribute(Attribute::Naked))
+ return false;
+
StringRef EntryAttr = PostInlining ? "instrument-function-entry-inlined"
: "instrument-function-entry";
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