[Driver][SYCL] Allow undefined symbols when doing host deps generation (#8743)

When processing archives when performing offload, the driver will
perform a host link which generates a file that is used to determine any
offload dependencies. This additional link step is just for gathering
the dependency information and shouldn't require the full ability to
link.

Under some circumstances, for example generating an early or final image
archive for FPGA, the symbol resolution is not important. Add a general
case of -z undefs during this internal link step and allow the final
host link to determine any unresolved symbols at that time.

Author: mdtoguchi

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -591,6 +591,13 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     ToolChain.addFastMathRuntimeIfAvailable(Args, CmdArgs);
   }
 
+  // Performing link for dependency file information, undefined symbols are OK.
+  // True link time errors for symbols will be captured at host link.
+  if (JA.getType() == types::TY_Host_Dependencies_Image) {
+    CmdArgs.push_back("-z");
+    CmdArgs.push_back("undefs");
+  }
+
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   Args.AddAllArgs(CmdArgs, options::OPT_u);
 

clang/test/Driver/sycl-offload-intelfpga-link.cpp

@@ -105,6 +105,14 @@
 // RUN:  | FileCheck %s --check-prefix=CHK-FPGA-LINK-WARN-AOCR
 // CHK-FPGA-LINK-WARN-AOCR: warning: FPGA archive '{{.*}}-aocr.a' does not contain matching emulation/hardware expectancy
 
+/// Check deps behaviors with input fat archive and creating aocx archive
+// RUN: %clangxx -fsycl -fintelfpga -fsycl-link=image \
+// RUN:          -target x86_64-unknown-linux-gnu %S/Inputs/SYCL/liblin64.a \
+// RUN:          %s -### 2>&1 \
+// RUN:  | FileCheck %s --check-prefix=CHK-FPGA-LINK-UNDEFS
+// CHK-FPGA-LINK-UNDEFS: ld{{.*}} "-z" "undefs"
+// CHK-FPGA-LINK-UNDEFS: clang-offload-deps{{.*}}
+
 /// -fintelfpga -fsycl-link from source
 // RUN: touch %t.cpp
 // RUN: %clangxx -target x86_64-unknown-linux-gnu -fsycl -fno-sycl-instrument-device-code -fno-sycl-device-lib=all -fintelfpga -fsycl-link=early %t.cpp -ccc-print-phases 2>&1 \

clang/test/Driver/sycl-offload-static-lib-2.cpp

@@ -150,7 +150,7 @@
 // RUN: %clangxx -target x86_64-unknown-linux-gnu -fsycl -fsycl-targets=nvptx64-nvidia-cuda %t_lib.a -o output_name -lOpenCL -### %s 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=STATIC_LIB_SRC2 -DBUNDLE_TRIPLE=sycl-nvptx64-nvidia-cuda-sm_50 -DDEPS_TRIPLE=sycl-nvptx64-nvidia-cuda-sm_50
 // STATIC_LIB_SRC2: clang{{.*}} "-emit-obj" {{.*}} "-o" "[[HOSTOBJ:.+\.o]]"
-// STATIC_LIB_SRC2: ld{{(.exe)?}}" {{.*}} "-o" "[[HOSTEXE:.+\.out]]"
+// STATIC_LIB_SRC2: ld{{(.exe)?}}" {{.*}} "-o" "[[HOSTEXE:.+\.out]]" {{.*}}"-z" "undefs"
 // STATIC_LIB_SRC2: clang-offload-deps{{.*}} "-targets=[[DEPS_TRIPLE]]" "-outputs=[[OUTDEPS:.+\.bc]]" "[[HOSTEXE]]"
 // STATIC_LIB_SRC2_DEF: clang-offload-bundler{{.*}} "-type=aoo" "-targets=[[BUNDLE_TRIPLE]]" {{.*}} "-output=[[OUTLIB:.+\.txt]]"
 // STATIC_LIB_SRC2_NVPTX: clang-offload-bundler{{.*}} "-type=a" "-targets=[[BUNDLE_TRIPLE]]" {{.*}} "-output=[[OUTLIB:.+\.a]]"