[Driver][SYCL] Fix -Xsycl option triple check with multiple -fsycl-targets (#4789)

When passing multiple -fsycl-targets on the command line, the last one wins.
There is a check for the number of target triples provided by the user when
applying -Xsycl-target* options to the device compilation.  We were
improperly counting all of the -fsycl-targets values instead of only taking
into account the last one only.

Author: mdtoguchi

clang/lib/Driver/ToolChain.cpp

@@ -1247,12 +1247,19 @@ llvm::opt::DerivedArgList *ToolChain::TranslateOffloadTargetArgs(
     if (XOffloadTargetNoTriple && XOffloadTargetArg) {
       // TODO: similar behaviors with OpenMP and SYCL offloading, can be
       // improved upon
+      auto SingleTargetTripleCount = [&Args](OptSpecifier Opt) {
+        const Arg *TargetArg = Args.getLastArg(Opt);
+        if (TargetArg && TargetArg->getValues().size() == 1)
+          return true;
+        return false;
+      };
       if (DeviceOffloadKind == Action::OFK_OpenMP &&
-          Args.getAllArgValues(options::OPT_fopenmp_targets_EQ).size() != 1) {
+          !SingleTargetTripleCount(options::OPT_fopenmp_targets_EQ)) {
         getDriver().Diag(diag::err_drv_Xopenmp_target_missing_triple);
         continue;
-      } else if (DeviceOffloadKind == Action::OFK_SYCL &&
-          Args.getAllArgValues(options::OPT_fsycl_targets_EQ).size() > 1) {
+      }
+      if (DeviceOffloadKind == Action::OFK_SYCL &&
+          !SingleTargetTripleCount(options::OPT_fsycl_targets_EQ)) {
         getDriver().Diag(diag::err_drv_Xsycl_target_missing_triple)
             << A->getSpelling();
         continue;

clang/lib/Driver/ToolChains/SYCL.cpp

@@ -734,7 +734,8 @@ void SYCLToolChain::TranslateTargetOpt(const llvm::opt::ArgList &Args,
     if (OptNoTriple) {
       // With multiple -fsycl-targets, a triple is required so we know where
       // the options should go.
-      if (Args.getAllArgValues(options::OPT_fsycl_targets_EQ).size() != 1) {
+      const Arg *TargetArg = Args.getLastArg(options::OPT_fsycl_targets_EQ);
+      if (TargetArg && TargetArg->getValues().size() != 1) {
         getDriver().Diag(diag::err_drv_Xsycl_target_missing_triple)
             << A->getSpelling();
         continue;

clang/test/Driver/sycl-offload.c

@@ -623,6 +623,16 @@
 // RUN:   | FileCheck -check-prefix=CHK-FSYCL-TARGET-AMBIGUOUS-ERROR %s
 // CHK-FSYCL-TARGET-AMBIGUOUS-ERROR: clang{{.*}} error: cannot deduce implicit triple value for '-Xsycl-target-backend', specify triple using '-Xsycl-target-backend=<triple>'
 
+/// Check -Xsycl-target-* does not trigger an error when multiple instances of
+/// -fsycl-targets is used.
+// RUN:   %clang -### -fsycl -fsycl-targets=spir64-unknown-unknown -fsycl-targets=spir64_gen-unknown-unknown -Xsycl-target-backend -DFOO %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-FSYCL-TARGET-2X-ERROR %s
+// RUN:   %clang -### -fsycl -fsycl-targets=spir64-unknown-unknown -fsycl-targets=spir64_gen-unknown-unknown -Xsycl-target-frontend -DFOO %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-FSYCL-TARGET-2X-ERROR %s
+// RUN:   %clang -### -fsycl -fsycl-targets=spir64-unknown-unknown -fsycl-targets=spir64_gen-unknown-unknown -Xsycl-target-linker -DFOO %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-FSYCL-TARGET-2X-ERROR %s
+// CHK-FSYCL-TARGET-2X-ERROR-NOT: clang{{.*}} error: cannot deduce implicit triple value for '-Xsycl-target{{.*}}', specify triple using '-Xsycl-target{{.*}}=<triple>'
+
 /// ###########################################################################
 
 /// Ahead of Time compilation for fpga, gen, cpu