AArch64: Move outline atomic libcalls configuration

[arsenm]

This de-conditionalizes the setting of the libcall names
on outlineAtomics() && !hasLSE(). The existence of the
libcall is a module level property, which cannot depend on the
subtarget so this is fine. It's better if the initial list of
calls has more entries than will be used than to have missing
ones. There aren't any alternative names set, so this is also
fine.

Currently RuntimeLibcallsInfo conflates the existence of the calls
with the lowering usage decision, so this suboptimally will report
the libcall name on subtargets that should not use the calls. This
doesn't matter in this case though, as the atomic lowering actions
are already separately controlled and aren't based on decisions on
libcall availability. We could be paranoid and clear the names in
TargetLowering.

Also fixes not catching all aarch64 triples in the RuntimeLibcallsInfo
construction; the previous check missed aarch64_be.

[arsenm]

• AArch64: Fix outline atomic libcall names for arm64ec #144378
• AArch64: Move outline atomic libcalls configuration #144374 👈 (View in Graphite)
• main

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[llvmbot]

@llvm/pr-subscribers-llvm-ir

@llvm/pr-subscribers-backend-aarch64

Author: Matt Arsenault (arsenm)

Changes

This de-conditionalizes the setting of the libcall names
on outlineAtomics() && !hasLSE(). The existence of the
libcall is a module level property, which cannot depend on the
subtarget so this is fine. It's better if the initial list of
calls has more entries than will be used than to have missing
ones. There aren't any alternative names set, so this is also
fine.

Currently RuntimeLibcallsInfo conflates the existence of the calls
with the lowering usage decision, so this suboptimally will report
the libcall name on subtargets that should not use the calls. This
doesn't matter in this case though, as the atomic lowering actions
are already separately controlled and aren't based on decisions on
libcall availability. We could be paranoid and clear the names in
TargetLowering.

Also fixes not catching all aarch64 triples in the RuntimeLibcallsInfo
construction; the previous check missed aarch64_be.

---

Full diff: https://github.com/llvm/llvm-project/pull/144374.diff

2 Files Affected:

• (modified) llvm/lib/IR/RuntimeLibcalls.cpp (+23-1)
• (modified) llvm/lib/Target/AArch64/AArch64ISelLowering.cpp (-21)

diff --git a/llvm/lib/IR/RuntimeLibcalls.cpp b/llvm/lib/IR/RuntimeLibcalls.cpp
index d63d398e243f9..09200f380305a 100644
--- a/llvm/lib/IR/RuntimeLibcalls.cpp
+++ b/llvm/lib/IR/RuntimeLibcalls.cpp
@@ -18,6 +18,28 @@ static cl::opt<bool>
 
 static void setAArch64LibcallNames(RuntimeLibcallsInfo &Info,
                                    const Triple &TT) {
+#define LCALLNAMES(A, B, N)                                                    \
+  Info.setLibcallName(A##N##_RELAX, #B #N "_relax");                           \
+  Info.setLibcallName(A##N##_ACQ, #B #N "_acq");                               \
+  Info.setLibcallName(A##N##_REL, #B #N "_rel");                               \
+  Info.setLibcallName(A##N##_ACQ_REL, #B #N "_acq_rel");
+#define LCALLNAME4(A, B)                                                       \
+  LCALLNAMES(A, B, 1)                                                          \
+  LCALLNAMES(A, B, 2) LCALLNAMES(A, B, 4) LCALLNAMES(A, B, 8)
+#define LCALLNAME5(A, B)                                                       \
+  LCALLNAMES(A, B, 1)                                                          \
+  LCALLNAMES(A, B, 2)                                                          \
+  LCALLNAMES(A, B, 4) LCALLNAMES(A, B, 8) LCALLNAMES(A, B, 16)
+  LCALLNAME5(RTLIB::OUTLINE_ATOMIC_CAS, __aarch64_cas)
+  LCALLNAME4(RTLIB::OUTLINE_ATOMIC_SWP, __aarch64_swp)
+  LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDADD, __aarch64_ldadd)
+  LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDSET, __aarch64_ldset)
+  LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDCLR, __aarch64_ldclr)
+  LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDEOR, __aarch64_ldeor)
+#undef LCALLNAMES
+#undef LCALLNAME4
+#undef LCALLNAME5
+
   if (TT.isWindowsArm64EC()) {
     // FIXME: are there calls we need to exclude from this?
 #define HANDLE_LIBCALL(code, name)                                             \
@@ -488,7 +510,7 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
     }
   }
 
-  if (TT.getArch() == Triple::ArchType::aarch64)
+  if (TT.isAArch64())
     setAArch64LibcallNames(*this, TT);
   else if (TT.isARM() || TT.isThumb())
     setARMLibcallNames(*this, TT);
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 7519ac5260a64..335e2ccadb084 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -966,27 +966,6 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::ATOMIC_LOAD_XOR, MVT::i16, LibCall);
     setOperationAction(ISD::ATOMIC_LOAD_XOR, MVT::i32, LibCall);
     setOperationAction(ISD::ATOMIC_LOAD_XOR, MVT::i64, LibCall);
-#define LCALLNAMES(A, B, N)                                                    \
-  setLibcallName(A##N##_RELAX, #B #N "_relax");                                \
-  setLibcallName(A##N##_ACQ, #B #N "_acq");                                    \
-  setLibcallName(A##N##_REL, #B #N "_rel");                                    \
-  setLibcallName(A##N##_ACQ_REL, #B #N "_acq_rel");
-#define LCALLNAME4(A, B)                                                       \
-  LCALLNAMES(A, B, 1)                                                          \
-  LCALLNAMES(A, B, 2) LCALLNAMES(A, B, 4) LCALLNAMES(A, B, 8)
-#define LCALLNAME5(A, B)                                                       \
-  LCALLNAMES(A, B, 1)                                                          \
-  LCALLNAMES(A, B, 2)                                                          \
-  LCALLNAMES(A, B, 4) LCALLNAMES(A, B, 8) LCALLNAMES(A, B, 16)
-    LCALLNAME5(RTLIB::OUTLINE_ATOMIC_CAS, __aarch64_cas)
-    LCALLNAME4(RTLIB::OUTLINE_ATOMIC_SWP, __aarch64_swp)
-    LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDADD, __aarch64_ldadd)
-    LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDSET, __aarch64_ldset)
-    LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDCLR, __aarch64_ldclr)
-    LCALLNAME4(RTLIB::OUTLINE_ATOMIC_LDEOR, __aarch64_ldeor)
-#undef LCALLNAMES
-#undef LCALLNAME4
-#undef LCALLNAME5
   }
 
   if (Subtarget->outlineAtomics() && !Subtarget->hasLSFE()) {

[efriedma-quic]

We might eventually want some mechanism that scans the module to see if, for example, there are any functions that might call the outlined atomic routines. A linker could use this to minimize the number of objects we pull into the link. But this is fine for now.

[arsenm]

Merge activity

• Jun 17, 12:42 AM UTC: A user started a stack merge that includes this pull request via Graphite.
• Jun 17, 12:44 AM UTC: Graphite rebased this pull request as part of a merge.
• Jun 17, 12:47 AM UTC: Graphite rebased this pull request as part of a merge.
• Jun 17, 12:49 AM UTC: @arsenm merged this pull request with Graphite.