[SYCL][Doc] Add SYCL compiler command line guide

Signed-off-by: Alexey Bader <alexey.bader@intel.com>

Author: bader

sycl/doc/SYCLCompilerAndRuntimeDesign.md

@@ -165,7 +165,7 @@ and single device compiler for this target is invoked.
 In the driver, the following bools are defined to determine the compilation
 mode in SYCL:
 
-* IsSYCL : True if the user has passed `--sycl` to the compilation
+* IsSYCL : True if the user has passed `-fsycl-device-only` to the compilation
 * IsSYCLOffloadDevice: True if calling clang to set up a device compilation
 * IsSYCLHost: True if setting up a call to clang to do a host compilation
 
@@ -396,7 +396,6 @@ llvm-no-spir-kernel host.bc
 It returns 0 if no kernels are present and 1 otherwise.
 
 
-
 ### Integration with SPIR-V format
 
 This section explains how to generate SPIR-V specific types and operations from

sycl/doc/SYCLCompilerUserManual.md

@@ -0,0 +1,182 @@
+# Overview
+
+The SYCL* Compiler contains many options to generate the desired binaries for
+your application.
+
+## SYCL specific command line options
+
+**`-fsycl`**
+
+    General enabling option for SYCL compilation mode.  This option enables
+    offload compilation for a given target using the `-fsycl-targets` option.
+    When the `-fsycl-targets` option is not provided, the default triple is
+    `spir64-unknown-[linux,windows]-sycldevice`.
+
+**`-fsycl-targets=<value>`**
+
+    A comma separated list of triples to specify the device target(s) to generate
+    code for.  This option is only valid when used with `-fsycl`.
+
+### Target toolchain options.
+
+**`-Xsycl-target-backend=<triple> <arg>`**
+
+    Pass <arg> to the SYCL based backend identified by <triple>.
+
+**`-Xsycl-target-backend <arg>`**
+
+    Pass <arg> to the SYCL based target backend.
+
+**`-Xsycl-target-frontend=<triple> <arg>`**
+
+    Pass <arg> to the SYCL based target frontend identified by <triple>.
+
+**`-Xsycl-target-frontend <arg>`**
+
+    Pass <arg> to the SYCL based target frontend.
+
+**`-Xsycl-target-linker=<triple> <arg>`**
+
+    Pass <arg> to the SYCL based target linker identified by <triple>.
+
+**`-Xsycl-target-linker <arg>`**
+
+    Pass <arg> to the SYCL based target linker.
+
+### Link options
+
+**`-fsycl-link`**
+
+    Generate partially linked device object to be used with the host link.
+
+**`-fsycl-link-targets=<T1,...,Tn>`**
+
+    Specify comma-separated list of triples SYCL offloading targets to produce
+    linked device images. Used in a link step to link device code for given
+    targets and output multiple linked device code images, whose names consist
+    of the common prefix taken from the -o option and the triple string.
+    Does not produce fat binary and must be used together with -fsycl.
+
+**`-fsycl-add-targets=<T1:file1...Tn:filen>`**
+
+    Add arbitrary device images to the fat binary being linked
+
+    Specify comma-separated list of triple and device binary image file name
+    pairs to add to the final SYCL binary. Tells clang to include given set of
+    device binaries into the fat SYCL binary when linking; the option value is
+    a set of pairs triple,filename - filename is treated as the device binary
+    image for the target triple it is paired with, and offload bundler is
+    invoked to do the actual bundling.
+
+**`-foffload-static-lib=<lib>`**
+
+    Link with fat static library.
+
+    Link with <lib>, which is a fat static archive containing fat objects which
+    correspond to the target device. When linking clang will extract the device
+    code from the objects contained in the library and link it with other
+    device objects coming from the individual fat objects passed on the command
+    line.
+    NOTE:  Any libraries that are passed on the command line which are not
+    specified with `-foffload-static-lib` are treated as host libraries and are
+    only used during the final host link.
+
+### Intel FPGA specific options
+
+**`-fintelfpga`**
+
+    Perform ahead of time compilation for FPGA.
+
+**`-fsycl-link=<value>`**
+
+    Generate partially linked device and host object to be used at various
+    stages of compilation. Takes the device binary(s) generated from a `-fsycl`
+    enabled compilation and wrap to create a host linkable object. This option
+    is enabled only in ahead of time compilation mode fore FPGA (i.e. when
+    `-fintelfpga` is set).
+
+**`-reuse-exe=<exe>`**
+
+    Speed up FPGA aoc compile if the device code in <exe> is unchanged.
+
+### Other options
+
+**`-fsycl-device-only`**
+
+    Compile only SYCL device code.
+
+**`-fsycl-use-bitcode`**
+
+    Emit SYCL device code in LLVM-IR bitcode format. When disabled, SPIR-V is
+    emitted. Default is true.
+
+**`-fno-sycl-use-bitcode`**
+
+    Use SPIR-V instead of LLVM bitcode in fat objects.
+
+**`-sycl-std=<value>`**
+
+    SYCL language standard to compile for.
+
+**`-fsycl-help`**
+
+    Emit help information from all of the offline compilation tools.
+
+**`-fsycl-help=<value>`**
+
+    Emit help information from the offline compilation tool associated with the
+    given architecture argument. Supported architectures: `x86_64`, `fpga` and
+    `gen`.
+
+**`-fsycl-unnamed-lambda`**
+
+    Allow unnamed SYCL lambda kernels.
+
+# SYCL device code compilation
+
+To invoke SYCL device compiler set `-fsycl-device-only` flag.
+
+```console
+$ clang++ -fsycl-device-only sycl-app.cpp -o sycl-app.bc
+```
+
+By default the output format for SYCL device is LLVM bytecode.
+
+`-fno-sycl-use-bitcode` can be used to emit device code in SPIR-V format.
+
+```console
+$ clang++ -fsycl-device-only -fno-sycl-use-bitcode sycl-app.cpp -o sycl-app.spv
+```
+
+# Static archives with SYCL device code
+
+The SYCL Compiler contains support to create and use static archives that
+contain device enabled fat objects.
+
+## Build your objects
+
+```console
+$ clang++ -fsycl sycl-app1.cpp sycl-app2.cpp -c
+```
+
+## Create the static archive
+
+Build the static archive in the same manner as you would any other normal
+static archive, using the objects that were created using the above step.
+
+```console
+$ ar cr libsyclapp.a sycl-app1.o sycl-app2.o
+```
+
+## Use the static archive
+
+Once you have created the archive, you can use it when creating your final
+application.  The fat archives are treated differently than a regular archive
+so the option `-foffload-static-lib` is used to signify the needed behavior.
+
+```console
+$ clang++ -fsycl sycl-main.cpp -foffload-static-lib=libsyclapp.a
+```
+
+Use of `-foffload-static-lib` is required or the library will be treated as
+a normal archive.