Add internal nogo analysis & checkescape tool.

See tools/nogo/README.md.

The checkescape tool is able to perform recursive escape analysis, using the
actual generated binary to confirm the results produced by the compiler itself.

As an initial use case, this replaces the manual escape analysis tests used for
go_marshal, and validates that the CopyIn and CopyOut paths will not require
any allocation or stack splits.

Updates #2243

PiperOrigin-RevId: 307532986

1 files changed, 31 insertions, 0 deletions

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+# Extended "nogo" analysis
+
+This package provides a build aspect that perform nogo analysis. This will be
+automatically injected to all relevant libraries when using the default
+`go_binary` and `go_library` rules.
+
+It exists for several reasons.
+
+*   The default `nogo` provided by bazel is insufficient with respect to the
+    possibility of binary analysis. This package allows us to analyze the
+    generated binary in addition to using the standard analyzers.
+
+*   The configuration provided in this package is much richer than the standard
+    `nogo` JSON blob. Specifically, it allows us to exclude specific structures
+    from the composite rules (such as the Ranges that are common with the set
+    types).
+
+*   The bazel version of `nogo` is run directly against the `go_library` and
+    `go_binary` targets, meaning that any change to the configuration requires a
+    rebuild from scratch (for some reason included all C++ source files in the
+    process). Using an aspect is more efficient in this regard.
+
+*   The checks supported by this package are exported as tests, which makes it
+    easier to reason about and plumb into the build system.
+
+*   For uninteresting reasons, it is impossible to integrate the default `nogo`
+    analyzer provided by bazel with internal Google tooling. To provide a
+    consistent experience, this package allows those systems to be unified.
+
+To use this package, import `nogo_test` from `defs.bzl` and add a single
+dependency which is a `go_binary` or `go_library` rule.