Adds a Bazel BUILD for LLVM.

Change: 139938302

1 files changed, 149 insertions, 0 deletions

diff --git a/third_party/llvm/llvm.bzl b/third_party/llvm/llvm.bzl
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+"""This file contains BUILD extensions for generating source code from LLVM's table definition files using the TableGen tool.
+
+See http://llvm.org/cmds/tblgen.html for more information on the TableGen
+tool.
+TODO(chandlerc): Currently this expresses include-based dependencies as
+"sources", and has no transitive understanding due to these files not being
+correctly understood by the build system.
+"""
+
+def gentbl(name, tblgen, td_file, td_srcs, tbl_outs, library = True, **kwargs):
+  """gentbl() generates tabular code from a table definition file.
+
+  Args:
+    name: The name of the build rule for use in dependencies.
+    tblgen: The binary used to produce the output.
+    td_file: The primary table definitions file.
+    td_srcs: A list of table definition files included transitively.
+    tbl_outs: A list of tuples (opts, out), where each opts is a string of
+      options passed to tblgen, and the out is the corresponding output file
+      produced.
+    library: Whether to bundle the generated files into a library.
+    **kwargs: Keyword arguments to pass to subsidiary cc_library() rule.
+  """
+  if td_file not in td_srcs:
+    td_srcs += [td_file]
+  includes = []
+  for (opts, out) in tbl_outs:
+    outdir = out[:out.rindex("/")]
+    if outdir not in includes:
+      includes.append(outdir)
+    rule_suffix = "_".join(opts.replace("-", "_").replace("=", "_").split(" "))
+    native.genrule(
+        name="%s_%s_genrule" % (name, rule_suffix),
+        srcs=td_srcs,
+        outs=[out],
+        tools=[tblgen],
+        message="Generating code from table: %s" % td_file,
+        cmd=(("$(location %s) " + "-I external/llvm/include " +
+              "-I external/llvm/tools/clang/include " +
+              "-I $$(dirname $(location %s)) " + "%s $(location %s) -o $@") % (
+                  tblgen, td_file, opts, td_file)))
+  # For now, all generated files can be assumed to comprise public interfaces.
+  # If this is not true, you should specify library = False
+  # and list the generated '.inc' files in "srcs".
+  if library:
+    native.cc_library(name=name, textual_hdrs=[f for (_, f) in tbl_outs],
+                      includes=includes,  **kwargs)
+
+
+# Rule for simple expansion of template files. This performs a simple
+# search over the template file for the keys in substitutions,
+# and replaces them with the corresponding values.
+#
+# Typical usage:
+#   load("/tools/build_rules/expand_header_template", "expand_header_template")
+#   expand_header_template(
+#       name = "ExpandMyTemplate",
+#       template = "my.template",
+#       out = "my.txt",
+#       substitutions = {
+#         "$VAR1": "foo",
+#         "$VAR2": "bar",
+#       }
+#   )
+#
+# Args:
+#   name: The name of the rule.
+#   template: The template file to expand
+#   out: The destination of the expanded file
+#   substitutions: A dictionary mapping strings to their substitutions
+
+def expand_header_template_impl(ctx):
+  ctx.template_action(
+      template = ctx.file.template,
+      output = ctx.outputs.out,
+      substitutions = ctx.attr.substitutions,
+  )
+
+expand_header_template = rule(
+    implementation = expand_header_template_impl,
+    attrs = {
+        "template": attr.label(mandatory=True, allow_files=True, single_file=True),
+        "substitutions": attr.string_dict(mandatory=True),
+        "out": attr.output(mandatory=True),
+    },
+    # output_to_genfiles is required for header files.
+    output_to_genfiles = True,
+)
+
+
+def llvm_target_cmake_vars(native_arch, target_triple):
+  return {
+      "LLVM_HOST_TRIPLE": target_triple,
+      "LLVM_DEFAULT_TARGET_TRIPLE": target_triple,
+      "LLVM_NATIVE_ARCH": native_arch,
+  }
+
+def _quote(s):
+  """Quotes the given string for use in a shell command.
+
+  This function double-quotes the given string (in case it contains spaces or
+  other special characters) and escapes any special characters (dollar signs,
+  double-quotes, and backslashes) that may be present.
+
+  Args:
+    s: The string to quote.
+  Returns:
+    An escaped and quoted version of the string that can be passed to a shell
+    command.
+  """
+  return ('"' +
+          s.replace("\\", "\\\\").replace("$", "\\$").replace('"', '\\"') +
+          '"')
+
+def cmake_var_string(cmake_vars):
+  """Converts a dictionary to an input suitable for expand_cmake_vars.
+
+  Ideally we would jist stringify in the expand_cmake_vars() rule, but select()
+  interacts badly with genrules.
+
+  TODO(phawkins): replace the genrule() with native rule and delete this rule.
+
+  Args:
+    cmake_vars: a dictionary with string keys and values that are convertable to
+      strings.
+  """
+  return " ".join([_quote("{}={}".format(k, str(v)))
+                   for (k, v) in cmake_vars.items()])
+
+def expand_cmake_vars(name, src, dst, cmake_vars):
+  """Expands #cmakedefine, #cmakedefine01, and CMake variables in a text file.
+
+  Args:
+    name: the name of the rule
+    src: the input of the rule
+    dst: the output of the rule
+    cmake_vars: a string containing the CMake variables, as generated by
+      cmake_var_string.
+  """
+  expand_cmake_vars_tool = "@//third_party/llvm:expand_cmake_vars"
+  native.genrule(
+      name = name,
+      srcs = [src],
+      tools = [expand_cmake_vars_tool],
+      outs = [dst],
+      cmd = ("$(location {}) ".format(expand_cmake_vars_tool) + cmake_vars +
+             "< $< > $@")
+  )
+