RuntimeLibcalls: Pass in FloatABI and EABI type #144691

arsenm · 2025-06-18T12:55:20Z

We need the full set of ABI options to accurately compute
the full set of libcalls. This partially resolves missing
information required to compute the set of ARM calls.

arsenm · 2025-06-18T12:55:38Z

RuntimeLibcalls: Pass in FloatABI and EABI type #144691 : 2 dependent PRs (#144692 , #144705 ) 👈 (View in Graphite)
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llvmbot · 2025-06-18T13:17:02Z

@llvm/pr-subscribers-llvm-binary-utilities
@llvm/pr-subscribers-backend-arm

@llvm/pr-subscribers-llvm-ir

Author: Matt Arsenault (arsenm)

Changes

We need the full set of ABI options to accurately compute
the full set of libcalls. This partially resolves missing
information required to compute the set of ARM calls.

Full diff: https://github.com/llvm/llvm-project/pull/144691.diff

5 Files Affected:

(modified) llvm/include/llvm/IR/RuntimeLibcalls.h (+7-3)
(modified) llvm/lib/CodeGen/TargetLoweringBase.cpp (+2-1)
(modified) llvm/lib/IR/RuntimeLibcalls.cpp (+15-3)
(modified) llvm/lib/Object/IRSymtab.cpp (+1-1)
(modified) llvm/lib/Target/ARM/ARMISelLowering.cpp (-10)

diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.h b/llvm/include/llvm/IR/RuntimeLibcalls.h
index 3e1531ebfd9d6..a6a180f5ed8db 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.h
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.h
@@ -19,6 +19,7 @@
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/Support/AtomicOrdering.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/TargetParser/Triple.h"
 
@@ -53,8 +54,10 @@ static inline auto libcalls() {
 
 /// A simple container for information about the supported runtime calls.
 struct RuntimeLibcallsInfo {
-  explicit RuntimeLibcallsInfo(const Triple &TT) {
-    initLibcalls(TT);
+  explicit RuntimeLibcallsInfo(const Triple &TT,
+                               FloatABI::ABIType FloatABI = FloatABI::Default,
+                               EABI EABIVersion = EABI::Default) {
+    initLibcalls(TT, FloatABI, EABIVersion);
   }
 
   /// Rename the default libcall routine name for the specified libcall.
@@ -144,7 +147,8 @@ struct RuntimeLibcallsInfo {
 
   /// Set default libcall names. If a target wants to opt-out of a libcall it
   /// should be placed here.
-  LLVM_ABI void initLibcalls(const Triple &TT);
+  LLVM_ABI void initLibcalls(const Triple &TT, FloatABI::ABIType FloatABI,
+                             EABI ABIType);
 };
 
 } // namespace RTLIB
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index b1afdc2a3ac39..2b5087cd38f55 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -632,7 +632,8 @@ void RTLIB::initCmpLibcallCCs(ISD::CondCode *CmpLibcallCCs) {
 
 /// NOTE: The TargetMachine owns TLOF.
 TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm)
-    : TM(tm), Libcalls(TM.getTargetTriple()) {
+    : TM(tm), Libcalls(TM.getTargetTriple(), TM.Options.FloatABIType,
+                       TM.Options.EABIVersion) {
   initActions();
 
   // Perform these initializations only once.
diff --git a/llvm/lib/IR/RuntimeLibcalls.cpp b/llvm/lib/IR/RuntimeLibcalls.cpp
index a57b089193462..74dccdf172d45 100644
--- a/llvm/lib/IR/RuntimeLibcalls.cpp
+++ b/llvm/lib/IR/RuntimeLibcalls.cpp
@@ -65,7 +65,17 @@ static void setAArch64LibcallNames(RuntimeLibcallsInfo &Info,
 #undef LCALLNAME5
 }
 
-static void setARMLibcallNames(RuntimeLibcallsInfo &Info, const Triple &TT) {
+static void setARMLibcallNames(RuntimeLibcallsInfo &Info, const Triple &TT,
+                               FloatABI::ABIType FloatABIType,
+                               EABI EABIVersion) {
+  if (!TT.isOSDarwin() && !TT.isiOS() && !TT.isWatchOS() && !TT.isDriverKit()) {
+    CallingConv::ID DefaultCC = FloatABIType == FloatABI::Hard
+                                    ? CallingConv::ARM_AAPCS_VFP
+                                    : CallingConv::ARM_AAPCS;
+    for (RTLIB::Libcall LC : RTLIB::libcalls())
+      Info.setLibcallCallingConv(LC, DefaultCC);
+  }
+
   // Register based DivRem for AEABI (RTABI 4.2)
   if (TT.isTargetAEABI() || TT.isAndroid() || TT.isTargetGNUAEABI() ||
       TT.isTargetMuslAEABI() || TT.isOSWindows()) {
@@ -346,7 +356,9 @@ static void setLongDoubleIsF128Libm(RuntimeLibcallsInfo &Info,
 
 /// Set default libcall names. If a target wants to opt-out of a libcall it
 /// should be placed here.
-void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
+void RuntimeLibcallsInfo::initLibcalls(const Triple &TT,
+                                       FloatABI::ABIType FloatABI,
+                                       EABI EABIVersion) {
   initSoftFloatCmpLibcallPredicates();
 
   initSoftFloatCmpLibcallPredicates();
@@ -539,7 +551,7 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
   if (TT.isAArch64())
     setAArch64LibcallNames(*this, TT);
   else if (TT.isARM() || TT.isThumb())
-    setARMLibcallNames(*this, TT);
+    setARMLibcallNames(*this, TT, FloatABI, EABIVersion);
   else if (TT.getArch() == Triple::ArchType::avr) {
     // Division rtlib functions (not supported), use divmod functions instead
     setLibcallName(RTLIB::SDIV_I8, nullptr);
diff --git a/llvm/lib/Object/IRSymtab.cpp b/llvm/lib/Object/IRSymtab.cpp
index 806477ae3de01..494ec089d7bd1 100644
--- a/llvm/lib/Object/IRSymtab.cpp
+++ b/llvm/lib/Object/IRSymtab.cpp
@@ -216,7 +216,7 @@ Expected<int> Builder::getComdatIndex(const Comdat *C, const Module *M) {
 static DenseSet<StringRef> buildPreservedSymbolsSet(const Triple &TT) {
   DenseSet<StringRef> PreservedSymbolSet(std::begin(PreservedSymbols),
                                          std::end(PreservedSymbols));
-
+  // FIXME: Do we need to pass in ABI fields from TargetOptions?
   RTLIB::RuntimeLibcallsInfo Libcalls(TT);
   for (const char *Name : Libcalls.getLibcallNames()) {
     if (Name)
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 05d8a1190ada8..500ce9dc364ee 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -508,16 +508,6 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM,
   setBooleanContents(ZeroOrOneBooleanContent);
   setBooleanVectorContents(ZeroOrNegativeOneBooleanContent);
 
-  if (!Subtarget->isTargetDarwin() && !Subtarget->isTargetIOS() &&
-      !Subtarget->isTargetWatchOS() && !Subtarget->isTargetDriverKit()) {
-    bool IsHFTarget = TM.Options.FloatABIType == FloatABI::Hard;
-
-    for (RTLIB::Libcall LC : RTLIB::libcalls()) {
-      setLibcallCallingConv(LC, IsHFTarget ? CallingConv::ARM_AAPCS_VFP
-                                           : CallingConv::ARM_AAPCS);
-    }
-  }
-
   if (Subtarget->isTargetMachO()) {
     // Uses VFP for Thumb libfuncs if available.
     if (Subtarget->isThumb() && Subtarget->hasVFP2Base() &&

smithp35

This looks reasonable to me. I've added the Arm maintainers just in case they've got anything to add.

smithp35 · 2025-06-18T15:37:47Z

llvm/lib/IR/RuntimeLibcalls.cpp

-static void setARMLibcallNames(RuntimeLibcallsInfo &Info, const Triple &TT) {
+static void setARMLibcallNames(RuntimeLibcallsInfo &Info, const Triple &TT,
+                               FloatABI::ABIType FloatABIType,
+                               EABI EABIVersion) {


The EABIVersion doesn't seem to be used by this function, or at least not yet.

Looks like it is only used in https://github.com/llvm/llvm-project/blob/main/llvm/lib/Target/ARM/ARMISelLowering.cpp#L693

Is the intention to move that part of the code to here at some point?

My apologies if I've missed some context, just seeing these reviews for the first time.

Yes, eventually the full list of possible libcalls should be recorded here. Later there will also need to be a separate mechanism for making context dependent lowering selections from the full set

nikic

LGTM

Strictly speaking I don't think we actually need the CC information at the IR level, but I also don't think that actually separating it makes sense.

arsenm · 2025-06-19T08:15:50Z

Strictly speaking I don't think we actually need the CC information at the IR level, but I also don't think that actually separating it makes sense.

You do if you want to emit a call from the IR. Some uses assume the calling convention and emit the call by name directly (e.g. asan) and I want to fix those eventually

arsenm · 2025-06-19T09:57:55Z

Merge activity

Jun 19, 9:57 AM UTC: A user started a stack merge that includes this pull request via Graphite.
Jun 19, 10:00 AM UTC: Graphite rebased this pull request as part of a merge.
Jun 19, 10:02 AM UTC: @arsenm merged this pull request with Graphite.

We need the full set of ABI options to accurately compute the full set of libcalls. This partially resolves missing information required to compute the set of ARM calls.

This was referenced Jun 18, 2025

MC: Move ExceptionHandling enum to Support #144692

Merged

RuntimeLibcalls: Pass in exception handling type #144696

Merged

arsenm requested review from DanielKristofKiss, dpaoliello, efriedma-quic, nikic, smithp35 and topperc June 18, 2025 13:13

arsenm marked this pull request as ready for review June 18, 2025 13:16

llvmbot added backend:ARM llvm:codegen llvm:ir llvm:binary-utilities labels Jun 18, 2025

arsenm mentioned this pull request Jun 18, 2025

ARM: Avoid using isTarget wrappers around Triple predicates #144705

Merged

smithp35 requested review from ostannard and nasherm June 18, 2025 15:34

smithp35 reviewed Jun 18, 2025

View reviewed changes

arsenm force-pushed the users/arsenm/runtime-libcalls/construct-from-float-abi-eabi-optios branch from 3bf268a to 1011a26 Compare June 19, 2025 01:32

nikic approved these changes Jun 19, 2025

View reviewed changes

RuntimeLibcalls: Pass in FloatABI and EABI type

4b38ca2

We need the full set of ABI options to accurately compute the full set of libcalls. This partially resolves missing information required to compute the set of ARM calls.

arsenm force-pushed the users/arsenm/runtime-libcalls/construct-from-float-abi-eabi-optios branch from 1011a26 to 4b38ca2 Compare June 19, 2025 09:59

arsenm merged commit 5bee2c3 into main Jun 19, 2025
5 of 7 checks passed

arsenm deleted the users/arsenm/runtime-libcalls/construct-from-float-abi-eabi-optios branch June 19, 2025 10:02

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