[clang] [llvm] [SYCL] Shorten triple form in device binary. (PR #231446)

[Kseniya Tikhomirova via cfe-commits]

https://github.com/KseniyaTikhomirova created https://github.com/llvm/llvm-project/pull/231446

The libsycl only needs to know which binary format the image holds,
and the architecture is the single canonical spelling of it: inputs may
spell the same target as 'spirv64' or 'spirv64-unknown-unknown'.
To avoid any runtime string copies or string manipulations,
shorten the packed form to carry only necessary data.

Assisted-by: Claude Code.

>From 78c74be3632f7a17e452d90a387eb6ff6f78ef84 Mon Sep 17 00:00:00 2001
From: "Tikhomirova, Kseniya" <kseniya.tikhomirova at intel.com>
Date: Tue, 13 Oct 2026 03:14:00 -0700
Subject: [PATCH] [SYCL] Shorten triple form in device binary

Signed-off-by: Tikhomirova, Kseniya <kseniya.tikhomirova at intel.com>
---
 .../OffloadTools/clang-sycl-linker/triple.ll   | 18 ++++++++++++++++++
 .../clang-sycl-linker/ClangSYCLLinker.cpp      |  6 +++++-
 .../src/detail/device_binary_structures.hpp    |  4 +++-
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/clang/test/OffloadTools/clang-sycl-linker/triple.ll b/clang/test/OffloadTools/clang-sycl-linker/triple.ll
index 7f432296acb8c..683941bab0e7c 100644
--- a/clang/test/OffloadTools/clang-sycl-linker/triple.ll
+++ b/clang/test/OffloadTools/clang-sycl-linker/triple.ll
@@ -10,6 +10,15 @@
 ; RUN:   | FileCheck %s --check-prefix=NO-TRIPLE-INPUT
 ; NO-TRIPLE-INPUT: sycl-bundle: image kind: spv, triple: spirv64, arch: {{$}}
 ;
+; Test that only the architecture is recorded in the offload image, both when
+; the full triple comes from -triple= and when it is inferred from the input.
+; RUN: clang-sycl-linker --dry-run -v -triple=spirv64-unknown-unknown %t/no-triple.bc -o %t/short-explicit.out 2>&1 \
+; RUN:   | FileCheck %s --check-prefix=SHORT-TRIPLE
+; RUN: llvm-as %t/full-triple.ll -o %t/full-triple.bc
+; RUN: clang-sycl-linker --dry-run -v %t/full-triple.bc -o %t/short-inferred.out 2>&1 \
+; RUN:   | FileCheck %s --check-prefix=SHORT-TRIPLE
+; SHORT-TRIPLE: sycl-bundle: image kind: spv, triple: spirv64, arch: {{$}}
+;
 ; Test that triple was inferred from inputs and recorded in the offload image.
 ; RUN: llvm-as %t/input1.ll -o %t/input1.bc
 ; RUN: llvm-as %t/input2.ll -o %t/input2.bc
@@ -81,6 +90,15 @@ define spir_kernel void @kernel_d() #0 {
 
 attributes #0 = { "sycl-module-id"="TU4.cpp" }
 
+;--- full-triple.ll
+target triple = "spirv64-unknown-unknown"
+
+define spir_kernel void @kernel_e() #0 {
+  ret void
+}
+
+attributes #0 = { "sycl-module-id"="TU5.cpp" }
+
 ;--- archive-full-triple.ll
 target triple = "spirv64-unknown-unknown"
 
diff --git a/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp b/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp
index 60ab7dc4e2a7d..e65ea5eb29b61 100644
--- a/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp
+++ b/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp
@@ -1043,8 +1043,12 @@ static Error runSYCLLink(ArrayRef<std::unique_ptr<MemoryBuffer>> Inputs,
     OffloadingImage TheImage{};
     TheImage.TheImageKind = IsAOTCompileNeeded ? IMG_Object : IMG_SPIRV;
     TheImage.TheOffloadKind = OFK_SYCL;
+    // Pack the short form of the triple. The runtime only needs to know which
+    // binary format the image holds, and the architecture is the single
+    // canonical spelling of it: inputs may spell the same target as 'spirv64'
+    // or 'spirv64-unknown-unknown'.
     TheImage.StringData["triple"] =
-        Args.MakeArgString(Result.TargetTriple.str());
+        Args.MakeArgString(Result.TargetTriple.getArchName());
     TheImage.StringData["arch"] =
         Args.MakeArgString(Args.getLastArgValue(OPT_arch_EQ));
     TheImage.StringData["symbols"] = SI.Symbols;
diff --git a/libsycl/src/detail/device_binary_structures.hpp b/libsycl/src/detail/device_binary_structures.hpp
index 29e71b45b3354..93aaafa8565f1 100644
--- a/libsycl/src/detail/device_binary_structures.hpp
+++ b/libsycl/src/detail/device_binary_structures.hpp
@@ -26,9 +26,11 @@ namespace detail {
 /// A device type represented by a particular target
 /// triple requires specific binary images. We need
 /// to map the image type onto the device target triple.
+/// clang-sycl-linker packs the short form of the triple, i.e. the
+/// architecture only, so these strings carry no vendor/OS components.
 
 /// SPIR-V with 64-bit pointers.
-static constexpr char DeviceBinaryTripleSPIRV64[] = "spirv64-unknown-unknown";
+static constexpr char DeviceBinaryTripleSPIRV64[] = "spirv64";
 
 } // namespace detail
 _LIBSYCL_END_NAMESPACE_SYCL