[bazel] Add support for --incompatible_disallow_empty_glob (#85999)

This bazel flag, that should be flipped in an upcoming release
bazelbuild/bazel#15327, fails if globs have no
matches. This helps find libraries where you are accidentally not
including files because of typos. This change removes the various globs
that were not matching anything, and uncovered some targets that were
doing nothing because their source files were deleted. There are a few
cases where globs were intentionally optional in the case of loops that
expanded to different potential options, so those now use `allow_empty =
True`. This allows downstream consumers to also flip this flags for
their own builds, where previously this would fail in LLVM instead.

The downside to this change is that if files are added in these
relatively standard locations, manual work will have to be done to add
this patterns back. If folks prefer we could instead add `allow_empty =
True` to every glob.

Author: keith

utils/bazel/.bazelrc

@@ -35,6 +35,10 @@ build --features=layering_check
 # See: https://bazel.build/reference/be/functions#exports_files
 build --incompatible_no_implicit_file_export
 
+# Enable so downstream users can flip this flag globally, this should
+# eventually become the default
+common --incompatible_disallow_empty_glob
+
 ###############################################################################
 # Options to select different strategies for linking potential dependent
 # libraries. The default leaves it disabled.

utils/bazel/llvm-project-overlay/bolt/BUILD.bazel

@@ -221,8 +221,6 @@ cc_library(
     srcs = glob([
         "lib/Target/AArch64/*.cpp",
     ]),
-    hdrs = glob([
-    ]),
     includes = ["include"],
     deps = [
         ":Core",

utils/bazel/llvm-project-overlay/clang-tools-extra/clang-tidy/defs.bzl

@@ -16,8 +16,8 @@ _common_library_deps = [
 ]
 
 def clang_tidy_library(name, **kwargs):
-    kwargs["srcs"] = kwargs.get("srcs", native.glob([paths.join(name, "*.cpp")]))
-    kwargs["hdrs"] = kwargs.get("hdrs", native.glob([paths.join(name, "*.h")]))
+    kwargs["srcs"] = kwargs.get("srcs", native.glob([paths.join(name, "*.cpp")], allow_empty = True))
+    kwargs["hdrs"] = kwargs.get("hdrs", native.glob([paths.join(name, "*.h")], allow_empty=True))
     kwargs["deps"] = kwargs.get("deps", []) + _common_library_deps
     cc_library(
         name = name,

utils/bazel/llvm-project-overlay/clang/BUILD.bazel

@@ -614,7 +614,6 @@ cc_library(
         "include/clang/Basic/Version.inc",
     ] + glob([
         "lib/Basic/*.cpp",
-        "lib/Basic/*.c",
         "lib/Basic/*.h",
         "lib/Basic/Targets/*.cpp",
         "lib/Basic/Targets/*.h",
@@ -1042,7 +1041,6 @@ cc_library(
         "lib/Analysis/FlowSensitive/Models/*.cpp",
         "lib/Analysis/FlowSensitive/*.cpp",
         "lib/Analysis/*.cpp",
-        "lib/Analysis/*.h",
     ]) + [
         ":analysis_htmllogger_gen",
     ],
@@ -1180,10 +1178,8 @@ gentbl(
 
 cc_library(
     name = "parse",
-    srcs = [
-    ] + glob([
+    srcs = glob([
         "lib/Parse/*.cpp",
-        "lib/Parse/*.h",
     ]),
     hdrs = [
         "include/clang/Parse/AttrParserStringSwitches.inc",
@@ -1207,7 +1203,6 @@ cc_library(
     name = "ast_matchers",
     srcs = glob([
         "lib/ASTMatchers/*.cpp",
-        "lib/ASTMatchers/*.h",
     ]),
     hdrs = glob(["include/clang/ASTMatchers/*.h"]),
     includes = ["include"],
@@ -1241,7 +1236,6 @@ cc_library(
     name = "rewrite",
     srcs = glob([
         "lib/Rewrite/*.cpp",
-        "lib/Rewrite/*.h",
     ]),
     hdrs = glob(["include/clang/Rewrite/Core/*.h"]),
     includes = ["include"],
@@ -1275,7 +1269,6 @@ cc_library(
     name = "tooling_core",
     srcs = glob([
         "lib/Tooling/Core/*.cpp",
-        "lib/Tooling/Core/*.h",
     ]),
     hdrs = glob(["include/clang/Tooling/Core/*.h"]),
     includes = ["include"],
@@ -1340,11 +1333,9 @@ cc_library(
     name = "tooling_refactoring",
     srcs = glob([
         "lib/Tooling/Refactoring/**/*.cpp",
-        "lib/Tooling/Refactoring/**/*.h",
     ]),
     hdrs = glob([
         "include/clang/Tooling/Refactoring/**/*.h",
-        "include/clang/Tooling/Refactoring/**/*.def",
     ]),
     deps = [
         ":ast",
@@ -1593,9 +1584,6 @@ cc_library(
     srcs = glob(
         [
             "lib/Driver/*.cpp",
-            "lib/Driver/*.h",
-            "lib/Driver/Arch/*.cpp",
-            "lib/Driver/Arch/*.h",
             "lib/Driver/ToolChains/*.cpp",
             "lib/Driver/ToolChains/*.h",
             "lib/Driver/ToolChains/Arch/*.cpp",
@@ -1833,9 +1821,6 @@ cc_library(
     copts = ["$(STACK_FRAME_UNLIMITED)"],
     data = [":builtin_headers_gen"],
     includes = ["include"],
-    textual_hdrs = glob([
-        "include/clang/Frontend/*.def",
-    ]),
     deps = [
         ":apinotes",
         ":ast",
@@ -1872,7 +1857,6 @@ cc_library(
     name = "frontend_rewrite",
     srcs = glob([
         "lib/Frontend/Rewrite/*.cpp",
-        "lib/Frontend/Rewrite/*.h",
     ]),
     hdrs = glob(["include/clang/Rewrite/Frontend/*.h"]),
     includes = ["include"],
@@ -2116,7 +2100,6 @@ cc_library(
     name = "frontend_tool",
     srcs = glob([
         "lib/FrontendTool/*.cpp",
-        "lib/FrontendTool/*.h",
     ]),
     hdrs = glob(["include/clang/FrontendTool/*.h"]),
     includes = ["include"],
@@ -2320,7 +2303,6 @@ cc_binary(
     testonly = 1,
     srcs = glob([
         "tools/clang-import-test/*.cpp",
-        "tools/clang-import-test/*.h",
     ]),
     stamp = 0,
     deps = [
@@ -2350,7 +2332,6 @@ cc_library(
     name = "clang-driver",
     srcs = glob([
         "tools/driver/*.cpp",
-        "tools/driver/*.h",
     ]) + ["clang-driver.cpp"],
     copts = [
         # Disable stack frame size checks in the driver because
@@ -2668,7 +2649,6 @@ cc_library(
     name = "extract_api",
     srcs = glob([
         "lib/ExtractAPI/**/*.cpp",
-        "lib/ExtractAPI/**/*.h",
     ]),
     hdrs = glob(["include/clang/ExtractAPI/**/*.h"]),
     includes = ["include"],

utils/bazel/llvm-project-overlay/lld/BUILD.bazel

@@ -187,7 +187,6 @@ cc_library(
     name = "MinGW",
     srcs = glob([
         "MinGW/*.cpp",
-        "MinGW/*.h",
     ]),
     includes = ["MinGW"],
     deps = [
@@ -296,7 +295,6 @@ cc_binary(
     name = "lld",
     srcs = glob([
         "tools/lld/*.cpp",
-        "tools/lld/*.h",
     ]) + ["lld-driver.cpp"],
     deps = [
         ":COFF",