[SYCL][Driver] Fix -save-temps for SYCL compilations (#1114)

Artem Gindinson · web-flow · commit f7f469948d10 · 2020-02-13T19:46:19.000+03:00
The following issues have been blocking the correct functioning
of -save-temps in the presence of -fsycl:

1. LLVM BC -&gt; host assembly transformation naturally crashes upon
encountering a SYCL device triple. Without -save-temps, this was
hidden due to compile/backend/assemble actions collapsing, however
the need to save all intermediate results uncovers the issue.
Solution: remove backend/assemble actions from the SYCL device flow
altogether, as these do not carry practical value anyway.

2. The integration header name being emptied by -save-temps enabling.
This is due to a bug in the llvm::sys::fs::real_path() function -
the Unix implementation doesn't guarantee a valid path for non-existent
files.
Solution: work around the issue by placing the Windows-specific caller
code under an OS preprocessor check.

Signed-off-by: Artem Gindinson &lt;artem.gindinson@intel.com&gt;
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
@@ -3270,14 +3270,20 @@ class OffloadingActionBuilder final {
         for (Action *&A : SYCLDeviceActions) {
           DeviceCompilerInput =
               C.MakeAction<CompileJobAction>(A, types::TY_SYCL_Header);
+          A = C.MakeAction<CompileJobAction>(A, types::TY_LLVM_BC);
         }
         DA.add(*DeviceCompilerInput, *ToolChains.front(), /*BoundArch=*/nullptr,
                Action::OFK_SYCL);
         // Clear the input file, it is already a dependence to a host
         // action.
         DeviceCompilerInput = nullptr;
+        return ABRT_Success;
       }
 
+      // Backend/Assemble actions are obsolete for the SYCL device side
+      if (CurPhase == phases::Backend || CurPhase == phases::Assemble)
+        return ABRT_Inactive;
+
       // The host only depends on device action in the linking phase, when all
       // the device images have to be embedded in the host image.
       if (CurPhase == phases::Link) {
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5978,16 +5978,29 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     // Inputs[1].  Include the header with -include
     if (!IsSYCLOffloadDevice && SYCLDeviceInput) {
       SmallString<128> RealPath;
+#if defined(_WIN32)
       // Fixup the header path name in case there are discrepancies in the
       // string used for the temporary directory environment variable and
       // actual path expectations.
+      //
+      // While generating the driver commands, we're most often working
+      // with non-existing files. The Unix implementation of LLVM's real_path
+      // returns an empty path for a non-existing file if it's expected to be
+      // placed in the current directory. This becomes a problem when we're
+      // saving intermediate compilation results via -save-temps.
+      // Since the header file path fix-up is Windows-specific, the real_path
+      // call is not necessary for a Unix-based OS (case-sensitive filesystem).
       llvm::sys::fs::real_path(SYCLDeviceInput->getFilename(), RealPath);
+#else  // _WIN32
+      RealPath.assign(StringRef(SYCLDeviceInput->getFilename()));
+#endif // _WIN32
+      const char *IntHeaderPath = Args.MakeArgString(RealPath);
       CmdArgs.push_back("-include");
-      CmdArgs.push_back(Args.MakeArgString(RealPath));
+      CmdArgs.push_back(IntHeaderPath);
       // When creating dependency information, filter out the generated
       // header file.
       CmdArgs.push_back("-dependency-filter");
-      CmdArgs.push_back(Args.MakeArgString(RealPath));
+      CmdArgs.push_back(IntHeaderPath);
       // Let the FE know we are doing a SYCL offload compilation, but we are
       // doing the host pass.
       CmdArgs.push_back("-fsycl-is-host");
diff --git a/clang/test/Driver/sycl-offload-intelfpga.cpp b/clang/test/Driver/sycl-offload-intelfpga.cpp
@@ -137,14 +137,12 @@
 // CHK-FPGA-LINK-SRC: 8: assembler, {7}, object, (host-sycl)
 // CHK-FPGA-LINK-SRC: 9: linker, {8}, archive, (host-sycl)
 // CHK-FPGA-LINK-SRC: 10: compiler, {3}, ir, (device-sycl)
-// CHK-FPGA-LINK-SRC: 11: backend, {10}, assembler, (device-sycl)
-// CHK-FPGA-LINK-SRC: 12: assembler, {11}, object, (device-sycl)
-// CHK-FPGA-LINK-SRC: 13: linker, {12}, ir, (device-sycl)
-// CHK-FPGA-LINK-SRC: 14: llvm-spirv, {13}, spirv, (device-sycl)
-// CHK-FPGA-LINK-SRC: 15: backend-compiler, {14}, fpga_aocr, (device-sycl)
-// CHK-FPGA-LINK-SRC: 16: clang-offload-wrapper, {15}, object, (device-sycl)
-// CHK-FPGA-LINK-SRC-DEFAULT: 17: offload, "host-sycl (x86_64-unknown-linux-gnu)" {9}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice)" {16}, archive
-// CHK-FPGA-LINK-SRC-CL: 17: offload, "host-sycl (x86_64-pc-windows-msvc)" {9}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice-coff)" {16}, archive
+// CHK-FPGA-LINK-SRC: 11: linker, {10}, ir, (device-sycl)
+// CHK-FPGA-LINK-SRC: 12: llvm-spirv, {11}, spirv, (device-sycl)
+// CHK-FPGA-LINK-SRC: 13: backend-compiler, {12}, fpga_aocr, (device-sycl)
+// CHK-FPGA-LINK-SRC: 14: clang-offload-wrapper, {13}, object, (device-sycl)
+// CHK-FPGA-LINK-SRC-DEFAULT: 15: offload, "host-sycl (x86_64-unknown-linux-gnu)" {9}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice)" {14}, archive
+// CHK-FPGA-LINK-SRC-CL: 15: offload, "host-sycl (x86_64-pc-windows-msvc)" {9}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice-coff)" {14}, archive
 
 /// -fintelfpga with -reuse-exe=
 // RUN:  touch %t.cpp
@@ -197,17 +195,15 @@
 // CHK-FPGA-AOCO-PHASES: 9: assembler, {8}, object, (host-sycl)
 // CHK-FPGA-AOCO-PHASES: 10: linker, {0, 9}, image, (host-sycl)
 // CHK-FPGA-AOCO-PHASES: 11: compiler, {4}, ir, (device-sycl)
-// CHK-FPGA-AOCO-PHASES: 12: backend, {11}, assembler, (device-sycl)
-// CHK-FPGA-AOCO-PHASES: 13: assembler, {12}, object, (device-sycl)
-// CHK-FPGA-AOCO-PHASES: 14: input, "[[INPUTA]]", archive
-// CHK-FPGA-AOCO-PHASES-LIN: 15: clang-offload-unbundler, {14}, object
-// CHK-FPGA-AOCO-PHASES-WIN: 15: clang-offload-unbundler, {14}, archive
-// CHK-FPGA-AOCO-PHASES: 16: linker, {13, 15}, ir, (device-sycl)
-// CHK-FPGA-AOCO-PHASES: 17: llvm-spirv, {16}, spirv, (device-sycl)
-// CHK-FPGA-AOCO-PHASES: 18: backend-compiler, {17}, fpga_aocx, (device-sycl)
-// CHK-FPGA-AOCO-PHASES: 19: clang-offload-wrapper, {18}, object, (device-sycl)
-// CHK-FPGA-AOCO-PHASES-LIN: 20: offload, "host-sycl (x86_64-unknown-linux-gnu)" {10}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice)" {19}, image
-// CHK-FPGA-AOCO-PHASES-WIN: 20: offload, "host-sycl (x86_64-pc-windows-msvc)" {10}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice-coff)" {19}, image
+// CHK-FPGA-AOCO-PHASES: 12: input, "[[INPUTA]]", archive
+// CHK-FPGA-AOCO-PHASES-LIN: 13: clang-offload-unbundler, {12}, object
+// CHK-FPGA-AOCO-PHASES-WIN: 13: clang-offload-unbundler, {12}, archive
+// CHK-FPGA-AOCO-PHASES: 14: linker, {11, 13}, ir, (device-sycl)
+// CHK-FPGA-AOCO-PHASES: 15: llvm-spirv, {14}, spirv, (device-sycl)
+// CHK-FPGA-AOCO-PHASES: 16: backend-compiler, {15}, fpga_aocx, (device-sycl)
+// CHK-FPGA-AOCO-PHASES: 17: clang-offload-wrapper, {16}, object, (device-sycl)
+// CHK-FPGA-AOCO-PHASES-LIN: 18: offload, "host-sycl (x86_64-unknown-linux-gnu)" {10}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice)" {17}, image
+// CHK-FPGA-AOCO-PHASES-WIN: 18: offload, "host-sycl (x86_64-pc-windows-msvc)" {10}, "device-sycl (spir64_fpga-unknown-unknown-sycldevice-coff)" {17}, image
 
 /// aoco test, checking tools
 // RUN:  %clangxx -target x86_64-unknown-linux-gnu -fsycl -fintelfpga -foffload-static-lib=%t_aoco.a -### %s 2>&1 \
diff --git a/clang/test/Driver/sycl-offload-static-lib.cpp b/clang/test/Driver/sycl-offload-static-lib.cpp
@@ -47,14 +47,12 @@
 // FOFFLOAD_STATIC_LIB_SRC: 9: assembler, {8}, object, (host-sycl)
 // FOFFLOAD_STATIC_LIB_SRC: 10: linker, {0, 9}, image, (host-sycl)
 // FOFFLOAD_STATIC_LIB_SRC: 11: compiler, {4}, ir, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 12: backend, {11}, assembler, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 13: assembler, {12}, object, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 14: input, "[[INPUTA]]", archive
-// FOFFLOAD_STATIC_LIB_SRC: 15: clang-offload-unbundler, {14}, object
-// FOFFLOAD_STATIC_LIB_SRC: 16: linker, {13, 15}, ir, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 17: llvm-spirv, {16}, spirv, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 18: clang-offload-wrapper, {17}, object, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 19: offload, "host-sycl (x86_64-unknown-linux-gnu)" {10}, "device-sycl (spir64-unknown-unknown-sycldevice)" {18}, image
+// FOFFLOAD_STATIC_LIB_SRC: 12: input, "[[INPUTA]]", archive
+// FOFFLOAD_STATIC_LIB_SRC: 13: clang-offload-unbundler, {12}, object
+// FOFFLOAD_STATIC_LIB_SRC: 14: linker, {11, 13}, ir, (device-sycl)
+// FOFFLOAD_STATIC_LIB_SRC: 15: llvm-spirv, {14}, spirv, (device-sycl)
+// FOFFLOAD_STATIC_LIB_SRC: 16: clang-offload-wrapper, {15}, object, (device-sycl)
+// FOFFLOAD_STATIC_LIB_SRC: 17: offload, "host-sycl (x86_64-unknown-linux-gnu)" {10}, "device-sycl (spir64-unknown-unknown-sycldevice)" {16}, image
 
 /// ###########################################################################
 
diff --git a/clang/test/Driver/sycl-offload-win.c b/clang/test/Driver/sycl-offload-win.c
@@ -76,14 +76,12 @@
 // FOFFLOAD_STATIC_LIB_SRC: 9: assembler, {8}, object, (host-sycl)
 // FOFFLOAD_STATIC_LIB_SRC: 10: linker, {0, 9}, image, (host-sycl)
 // FOFFLOAD_STATIC_LIB_SRC: 11: compiler, {4}, ir, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 12: backend, {11}, assembler, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 13: assembler, {12}, object, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 14: input, "[[INPUTLIB]]", archive
-// FOFFLOAD_STATIC_LIB_SRC: 15: clang-offload-unbundler, {14}, archive
-// FOFFLOAD_STATIC_LIB_SRC: 16: linker, {13, 15}, ir, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 17: llvm-spirv, {16}, spirv, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 18: clang-offload-wrapper, {17}, object, (device-sycl)
-// FOFFLOAD_STATIC_LIB_SRC: 19: offload, "host-sycl (x86_64-pc-windows-msvc)" {10}, "device-sycl (spir64-unknown-unknown-sycldevice{{(-coff)?}})" {18}, image
+// FOFFLOAD_STATIC_LIB_SRC: 12: input, "[[INPUTLIB]]", archive
+// FOFFLOAD_STATIC_LIB_SRC: 13: clang-offload-unbundler, {12}, archive
+// FOFFLOAD_STATIC_LIB_SRC: 14: linker, {11, 13}, ir, (device-sycl)
+// FOFFLOAD_STATIC_LIB_SRC: 15: llvm-spirv, {14}, spirv, (device-sycl)
+// FOFFLOAD_STATIC_LIB_SRC: 16: clang-offload-wrapper, {15}, object, (device-sycl)
+// FOFFLOAD_STATIC_LIB_SRC: 17: offload, "host-sycl (x86_64-pc-windows-msvc)" {10}, "device-sycl (spir64-unknown-unknown-sycldevice{{(-coff)?}})" {16}, image
 
 /// ###########################################################################
 
diff --git a/clang/test/Driver/sycl-offload-with-split.c b/clang/test/Driver/sycl-offload-with-split.c
diff --git a/clang/test/Driver/sycl-offload.c b/clang/test/Driver/sycl-offload.c
