iree-bazel-* improvements for handling multiple targets + options. (#23330)

iree-bazel-try:
- supports --features, useful for --features=thin_lto
- workaround for thin_lto + Wno-unused-command-line-argument
- --copt and --linkopt in a way that ensures the entire build is
  configured with the options (prior only the try target was, which was
  useful in isolated testing but not when benchmarking/etc)
- uses a new output base (so features/copt/linkopt don't pollute the
  normal build, good for concurrent try + build/test)
- fixed caching of files passed in by path
- fixed files passed in by path to have original source locations

iree-bazel-test/build/fuzz:
- support multiple targets (`iree-bazel-test //:a //:b`)
- this allows multiple fuzzers to run in batched mode

iree-bazel-cquery:
- added to match iree-bazel-query so we have the pair

misc:
- `target_compatible_with`/platform `select` support in bazel-to-cmake
- fixing benchmark warnings about missing unit
- fixed a bug in cc_benchmark dropping extra args on benchmark tests

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: benvanik

build_tools/bazel/BUILD.bazel

@@ -28,3 +28,20 @@ config_setting(
         "iree_is_android": "true",
     },
 )
+
+# OS platform constraints. Used in select() for platform-specific backend
+# selection. bazel_to_cmake maps these to CMAKE_SYSTEM_NAME checks.
+config_setting(
+    name = "iree_is_linux",
+    constraint_values = ["@platforms//os:linux"],
+)
+
+config_setting(
+    name = "iree_is_macos",
+    constraint_values = ["@platforms//os:macos"],
+)
+
+config_setting(
+    name = "iree_is_windows",
+    constraint_values = ["@platforms//os:windows"],
+)

build_tools/bazel/cc_binary_benchmark.bzl

@@ -8,7 +8,7 @@
 
 It's good to test that benchmarks run, but it's really annoying to run a billion
 iterations of them every time you try to run tests. So we create these as
-binaries and then invoke them as tests with `--benchmark_min_time=0`.
+binaries and then invoke them as tests with `--benchmark_min_time=0s`.
 """
 
 load(":native_binary.bzl", "native_test")
@@ -25,13 +25,14 @@ def cc_binary_benchmark(
         testonly = True,
         size = "small",
         timeout = None,
+        args = None,
         **kwargs):
     """Creates a binary and a test for a cc benchmark target.
 
     Arguments passed to the binary target:
       name, srcs, data, deps, copts, defines, linkopts, tags, testonly, **kwargs
     Arguments passed to the test target:
-      {name}_test, tags, size, timeout, **kwargs
+      {name}_test, tags, size, timeout, args (merged with --benchmark_min_time=0s), **kwargs
     """
     native.cc_binary(
         name = name,
@@ -46,12 +47,17 @@ def cc_binary_benchmark(
         **kwargs
     )
 
+    # Merge args: enforced flag first, then user args.
+    test_args = ["--benchmark_min_time=0s"]
+    if args:
+        test_args = test_args + args
+
     native_test(
         name = "{}_test".format(name),
         src = name,
         size = size,
         tags = tags,
         timeout = timeout,
-        args = ["--benchmark_min_time=0"],
+        args = test_args,
         **kwargs
     )

build_tools/bazel/iree.bazelrc

@@ -57,16 +57,15 @@ build --flag_alias=iree_enable_runtime_tracing=//runtime/src/iree/base/tracing:t
 #
 # Combines several optimizations for faster local iteration:
 # - Skymeld (merged analysis/execution for faster multi-target builds)
-# - Ramdisk sandbox on Linux (reduces I/O bottleneck with many cores)
 #
-# Note: Disk cache is configured in user.bazelrc (created by iree-bazel-configure).
+# Note: Disk cache and platform-specific settings (e.g., Linux ramdisk sandbox)
+# are configured in user.bazelrc (created by iree-bazel-configure).
 ###############################################################################
 
-build:localdev --experimental_merged_skyframe_analysis_execution
+# Default (allows --config=localdev for consistency).
+query:localdev --output=label
 
-# Linux: use ramdisk for sandbox to reduce I/O with many cores.
-# This is a no-op on other platforms.
-build:localdev --sandbox_base=/dev/shm
+build:localdev --experimental_merged_skyframe_analysis_execution
 
 ###############################################################################
 # Options for "generic_gcc" builds