[llvm] [llvm-jitlink] Use MachOObjectFile::getArchTriple for triple identifi… (PR #161799)

[Lang Hames via llvm-commits]

https://github.com/lhames created https://github.com/llvm/llvm-project/pull/161799

…cation.

Replaces a call to ObjectFile::makeTriple (still used for ELF and COFF) with a call to MachOObjectFile::getArchTriple. The latter knows how to build correct triples for different MachO CPU subtypes, e.g. arm64 vs arm64e, which is important for selecting the right slice from universal archives.

>From 0760d86743cd0d53f98dca32034794217e98dae8 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames at gmail.com>
Date: Fri, 3 Oct 2025 16:53:33 +1000
Subject: [PATCH] [llvm-jitlink] Use MachOObjectFile::getArchTriple for triple
 identification.

Replaces a call to ObjectFile::makeTriple (still used for ELF and COFF) with a
call to MachOObjectFile::getArchTriple. The latter knows how to build correct
triples for different MachO CPU subtypes, e.g. arm64 vs arm64e, which is
important for selecting the right slice from universal archives.
---
 .../JITLink/AArch64/Inputs/x-0.s              |  7 ++++
 .../JITLink/AArch64/Inputs/x-1.s              |  7 ++++
 .../AArch64/MachO_universal_slice_selection.s | 32 +++++++++++++++++++
 llvm/tools/llvm-jitlink/llvm-jitlink.cpp      |  6 +++-
 4 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-0.s
 create mode 100644 llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-1.s
 create mode 100644 llvm/test/ExecutionEngine/JITLink/AArch64/MachO_universal_slice_selection.s

diff --git a/llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-0.s b/llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-0.s
new file mode 100644
index 0000000000000..557e4033d4c93
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-0.s
@@ -0,0 +1,7 @@
+	.section	__DATA,__data
+	.globl	x
+	.p2align	2, 0x0
+x:
+	.long	0
+
+.subsections_via_symbols
diff --git a/llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-1.s b/llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-1.s
new file mode 100644
index 0000000000000..711c8a03d634b
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/AArch64/Inputs/x-1.s
@@ -0,0 +1,7 @@
+	.section	__DATA,__data
+	.globl	x
+	.p2align	2, 0x0
+x:
+	.long	1
+
+.subsections_via_symbols
diff --git a/llvm/test/ExecutionEngine/JITLink/AArch64/MachO_universal_slice_selection.s b/llvm/test/ExecutionEngine/JITLink/AArch64/MachO_universal_slice_selection.s
new file mode 100644
index 0000000000000..c58f84e7e7325
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/AArch64/MachO_universal_slice_selection.s
@@ -0,0 +1,32 @@
+# RUN: rm -rf %t && mkdir -p %t
+# RUN: llvm-mc -triple=arm64e-apple-darwin -filetype=obj -o %t/main.o %s
+# RUN: llvm-mc -triple=arm64-apple-darwin -filetype=obj -o %t/x.arm64.o \
+# RUN:     %S/Inputs/x-1.s
+# RUN: llvm-ar crs %t/libX.arm64.a %t/x.arm64.o
+# RUN: llvm-mc -triple=arm64e-apple-darwin -filetype=obj -o %t/x.arm64e.o \
+# RUN:     %S/Inputs/x-0.s
+# RUN: llvm-ar crs %t/libX.arm64e.a %t/x.arm64e.o
+# RUN: llvm-lipo --create --output %t/libX.a %t/libX.arm64.a %t/libX.arm64e.a
+# RUN: llvm-jitlink -noexec -check=%s %t/main.o -L%t -lX
+#
+# Create a universal archive with two slices (arm64e, arm64) each containing
+# a definition of X: in arm64e X = 0, in arm64 X = 1.
+# Check that if we load an arm64e object file then we link the arm64e slice
+# of the archive by verifying that X = 0.
+#
+
+# jitlink-check: *{4}x = 0
+
+	.section	__TEXT,__text,regular,pure_instructions
+	.globl	_main
+	.p2align	2
+_main:
+	mov     w0, #0
+        ret
+
+	.section	__DATA,__data
+	.globl	p
+p:
+	.quad   x
+
+.subsections_via_symbols
diff --git a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
index e09ddb45da6e9..731d64877ac63 100644
--- a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
+++ b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
@@ -1636,7 +1636,11 @@ static std::pair<Triple, SubtargetFeatures> getFirstFileTripleAndFeatures() {
       case file_magic::macho_object: {
         auto Obj = ExitOnErr(
             object::ObjectFile::createObjectFile(ObjBuffer->getMemBufferRef()));
-        Triple TT = Obj->makeTriple();
+        Triple TT;
+        if (auto *MachOObj = dyn_cast<object::MachOObjectFile>(Obj.get()))
+          TT = MachOObj->getArchTriple();
+        else
+          TT = Obj->makeTriple();
         if (Magic == file_magic::coff_object) {
           // TODO: Move this to makeTriple() if possible.
           TT.setObjectFormat(Triple::COFF);