[clang] 2bd77c8 - [SYCL][Driver] Pass path to libsycl.so by default for SYCL compilation. (#174877)

[via cfe-commits]

Author: Srividya Sundaram
Date: 2026-02-13T19:15:01-06:00
New Revision: 2bd77c83596a5336608ba7a07810a57686222a23

URL: https://github.com/llvm/llvm-project/commit/2bd77c83596a5336608ba7a07810a57686222a23
DIFF: https://github.com/llvm/llvm-project/commit/2bd77c83596a5336608ba7a07810a57686222a23.diff

LOG: [SYCL][Driver] Pass path to libsycl.so by default for SYCL compilation. (#174877)

This patch updates the default behavior for `SYCL` offload compilations.

Specifically, we now pass the path to the SYCL runtime library,
`libsycl.so`, by default to the `clang-linker-wrapper` tool, which is
responsible for linking the `SYCL` runtime library. We also add the SYCL
header include paths by default to both the SYCL host and device
compilations.

Added: 
    

Modified: 
    clang/include/clang/Driver/SyclInstallationDetector.h
    clang/lib/Driver/ToolChains/Linux.cpp
    clang/lib/Driver/ToolChains/SYCL.cpp
    clang/test/Driver/sycl-offload-jit.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Driver/SyclInstallationDetector.h b/clang/include/clang/Driver/SyclInstallationDetector.h
index 6925ec24bcd29..f92228817f045 100644
--- a/clang/include/clang/Driver/SyclInstallationDetector.h
+++ b/clang/include/clang/Driver/SyclInstallationDetector.h
@@ -21,6 +21,14 @@ class SYCLInstallationDetector {
 
   void addSYCLIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                           llvm::opt::ArgStringList &CC1Args) const;
+
+  // Return the filesystem path to the SYCL runtime library (libsycl.so), that
+  // was detected.
+  StringRef getSYCLRTLibPath() const { return SYCLRTLibPath; }
+
+private:
+  const Driver &D;
+  SmallString<0> SYCLRTLibPath;
 };
 
 } // namespace driver

diff  --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
index fb3f531e77ace..a5277dcac1747 100644
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -863,6 +863,8 @@ void Linux::addOffloadRTLibs(unsigned ActiveKinds, const ArgList &Args,
   llvm::SmallVector<std::pair<StringRef, StringRef>> Libraries;
   if (ActiveKinds & Action::OFK_HIP)
     Libraries.emplace_back(RocmInstallation->getLibPath(), "libamdhip64.so");
+  else if (ActiveKinds & Action::OFK_SYCL)
+    Libraries.emplace_back(SYCLInstallation->getSYCLRTLibPath(), "libsycl.so");
 
   for (auto [Path, Library] : Libraries) {
     if (Args.hasFlag(options::OPT_frtlib_add_rpath,

diff  --git a/clang/lib/Driver/ToolChains/SYCL.cpp b/clang/lib/Driver/ToolChains/SYCL.cpp
index 85859f344b491..033fd98183737 100644
--- a/clang/lib/Driver/ToolChains/SYCL.cpp
+++ b/clang/lib/Driver/ToolChains/SYCL.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 #include "SYCL.h"
 #include "clang/Driver/CommonArgs.h"
+#include "llvm/Support/VirtualFileSystem.h"
 
 using namespace clang::driver;
 using namespace clang::driver::toolchains;
@@ -16,16 +17,32 @@ using namespace llvm::opt;
 
 SYCLInstallationDetector::SYCLInstallationDetector(
     const Driver &D, const llvm::Triple &HostTriple,
-    const llvm::opt::ArgList &Args) {}
+    const llvm::opt::ArgList &Args)
+    : D(D) {
+  // Detect the presence of the SYCL runtime library (libsycl.so) in the
+  // filesystem. This is used to determine whether a usable SYCL installation
+  // is available for the current driver invocation.
+  StringRef SysRoot = D.SysRoot;
+  SmallString<128> DriverDir(D.Dir);
+  if (DriverDir.starts_with(SysRoot) &&
+      (Args.hasArg(options::OPT_fsycl) ||
+       D.getVFS().exists(DriverDir + "/../lib/libsycl.so"))) {
+    llvm::sys::path::append(DriverDir, "..", "lib");
+    SYCLRTLibPath = DriverDir;
+  }
+}
 
 void SYCLInstallationDetector::addSYCLIncludeArgs(
     const ArgList &DriverArgs, ArgStringList &CC1Args) const {
   if (DriverArgs.hasArg(options::OPT_nobuiltininc))
     return;
 
-  // Add the SYCL header search locations in the specified order.
-  // FIXME: Add the header file locations once the SYCL library and headers
-  //        are properly established within the build.
+  // Add the SYCL header search locations.
+  // These are included for both SYCL host and device compilations.
+  SmallString<128> IncludePath(D.Dir);
+  llvm::sys::path::append(IncludePath, "..", "include");
+  CC1Args.push_back("-internal-isystem");
+  CC1Args.push_back(DriverArgs.MakeArgString(IncludePath));
 }
 
 // Unsupported options for SYCL device compilation.

diff  --git a/clang/test/Driver/sycl-offload-jit.cpp b/clang/test/Driver/sycl-offload-jit.cpp
index 72c2390a3fe4b..5bdb56d935a98 100644
--- a/clang/test/Driver/sycl-offload-jit.cpp
+++ b/clang/test/Driver/sycl-offload-jit.cpp
@@ -29,6 +29,14 @@
 // CHK-DEVICE-TRIPLE-SAME: "-O2"
 // CHK-DEVICE-TRIPLE: llvm-offload-binary{{.*}} "--image=file={{.*}}.bc,triple=spirv64-unknown-unknown,arch=generic,kind=sycl"
 
+// Check if path to libsycl.so is passed to clang-linker-wrapper tool by default for SYCL compilation.
+// The test also checks if SYCL header include paths are added to the SYCL host and device compilation.
+// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fsycl %s 2>&1 \
+// RUN:   | FileCheck -check-prefixes=CHECK-LSYCL,CHECK-SYCL-HEADERS-HOST,CHECK-SYCL-HEADERS-DEVICE %s
+// CHECK-SYCL-HEADERS-DEVICE: "-fsycl-is-device"{{.*}} "-internal-isystem" "{{.*}}bin{{[/\\]+}}..{{[/\\]+}}include"
+// CHECK-SYCL-HEADERS-HOST: "-fsycl-is-host"{{.*}} "-internal-isystem" "{{.*}}bin{{[/\\]+}}..{{[/\\]+}}include"
+// CHECK-LSYCL: clang-linker-wrapper{{.*}} "{{.*}}bin{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}libsycl.so"
+
 /// Check -fsycl-is-device is passed when compiling for the device.
 /// Check -fsycl-is-host is passed when compiling for host.
 // RUN: %clang -### -fsycl -c %s 2>&1 \