From cc9b40d3a14338a738639684560d81e7716cfe7e Mon Sep 17 00:00:00 2001
From: Christian Legnitto <christian@legnitto.com>
Date: Thu, 2 Jan 2025 15:50:12 -0400
Subject: [PATCH] Add tracing to rustc_codegen_spirv

Fixes https://github.com/Rust-GPU/rust-gpu/issues/192
---
 .github/workflows/lint.sh             |  10 +-
 Cargo.lock                            | 232 ++++++++++++++++++++------
 Cargo.toml                            |   2 +
 crates/rustc_codegen_spirv/Cargo.toml |   3 +
 crates/rustc_codegen_spirv/src/lib.rs |  74 ++++++++
 deny.toml                             |   2 +
 6 files changed, 271 insertions(+), 52 deletions(-)

diff --git a/.github/workflows/lint.sh b/.github/workflows/lint.sh
index 31941a5084..66f2d362d5 100755
--- a/.github/workflows/lint.sh
+++ b/.github/workflows/lint.sh
@@ -49,10 +49,16 @@ clippy_no_features examples/shaders/simplest-shader
 # which could be disastrous because env vars access can't be tracked by
 # `rustc`, unlike its CLI flags (which are integrated with incremental).
 if (
-    egrep -r '::\s*env|env\s*::' crates/rustc_codegen_spirv/src/ |
+    egrep -r '::\s*env|env\s*::' crates/rustc_codegen_spirv/src |
     # HACK(eddyb) exclude the one place in `rustc_codegen_spirv`
     # needing access to an env var (only for codegen args `--help`).
-    egrep -v '^crates/rustc_codegen_spirv/src/codegen_cx/mod.rs:            let help_flag_comes_from_spirv_builder_env_var = std::env::var\(spirv_builder_env_var\)$'
+    egrep -v '^crates/rustc_codegen_spirv/src/codegen_cx/mod.rs:            let help_flag_comes_from_spirv_builder_env_var = std::env::var\(spirv_builder_env_var\)$' |
+    # HACK(LegNeato) exclude logging. This mirrors `rustc` (`RUSTC_LOG`) and 
+    #`rustdoc` (`RUSTDOC_LOG`).
+    # There is not a risk of this being disastrous as it does not change the build settings.
+    egrep -v '^crates/rustc_codegen_spirv/src/lib.rs:.*(RUSTGPU_LOG|RUSTGPU_LOG_FORMAT|RUSTGPU_LOG_COLOR).*$' |
+    egrep -v '^crates/rustc_codegen_spirv/src/lib.rs:    use std::env::{self, VarError};$'
+
 ); then
     echo '^^^'
     echo '!!! Found disallowed `std::env` usage in `rustc_codegen_spirv` !!!'
diff --git a/Cargo.lock b/Cargo.lock
index 7d2bd39a42..da6f67b17b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -156,9 +156,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.94"
+version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1fd03a028ef38ba2276dce7e33fcd6369c158a1bca17946c4b1b701891c1ff7"
+checksum = "34ac096ce696dc2fcabef30516bb13c0a68a11d30131d3df6f04711467681b04"
 
 [[package]]
 name = "ar"
@@ -284,18 +284,18 @@ checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"
 
 [[package]]
 name = "bytemuck"
-version = "1.20.0"
+version = "1.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8b37c88a63ffd85d15b406896cc343916d7cf57838a847b3a6f2ca5d39a5695a"
+checksum = "ef657dfab802224e671f5818e9a4935f9b1957ed18e58292690cc39e7a4092a3"
 dependencies = [
  "bytemuck_derive",
 ]
 
 [[package]]
 name = "bytemuck_derive"
-version = "1.8.0"
+version = "1.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bcfcc3cd946cb52f0bbfdbbcfa2f4e24f75ebb6c0e1002f7c25904fada18b9ec"
+checksum = "3fa76293b4f7bb636ab88fd78228235b5248b4d05cc589aed610f954af5d7c7a"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -336,9 +336,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.2.4"
+version = "1.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9157bbaa6b165880c27a4293a474c91cdcf265cc68cc829bf10be0964a391caf"
+checksum = "8d6dbb628b8f8555f86d0323c2eb39e3ec81901f4b83e091db8a6a76d316a333"
 dependencies = [
  "jobserver",
  "libc",
@@ -598,18 +598,18 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-channel"
-version = "0.5.13"
+version = "0.5.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "33480d6946193aa8033910124896ca395333cae7e2d1113d1fef6c3272217df2"
+checksum = "06ba6d68e24814cb8de6bb986db8222d3a027d15872cabc0d18817bc3c0e4471"
 dependencies = [
  "crossbeam-utils",
 ]
 
 [[package]]
 name = "crossbeam-deque"
-version = "0.8.5"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
 dependencies = [
  "crossbeam-epoch",
  "crossbeam-utils",
@@ -745,9 +745,9 @@ dependencies = [
 
 [[package]]
 name = "env_filter"
-version = "0.1.2"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f2c92ceda6ceec50f43169f9ee8424fe2db276791afde7b2cd8bc084cb376ab"
+checksum = "186e05a59d4c50738528153b83b0b0194d3a29507dfec16eccd4b342903397d0"
 dependencies = [
  "log",
  "regex",
@@ -755,9 +755,9 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.11.5"
+version = "0.11.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e13fa619b91fb2381732789fc5de83b45675e882f66623b7d8cb4f643017018d"
+checksum = "dcaee3d8e3cfc3fd92428d477bc97fc29ec8716d180c0d74c643bb26166660e0"
 dependencies = [
  "anstream",
  "anstyle",
@@ -877,9 +877,9 @@ dependencies = [
 
 [[package]]
 name = "foldhash"
-version = "0.1.3"
+version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f81ec6369c545a7d40e4589b5597581fa1c441fe1cce96dd1de43159910a36a2"
+checksum = "a0d2fde1f7b3d48b8395d5f2de76c18a528bd6a9cdde438df747bfcba3e05d6f"
 
 [[package]]
 name = "foreign-types"
@@ -1122,13 +1122,13 @@ dependencies = [
 
 [[package]]
 name = "gpu-descriptor"
-version = "0.3.0"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c08c1f623a8d0b722b8b99f821eb0ba672a1618f0d3b16ddbee1cedd2dd8557"
+checksum = "dcf29e94d6d243368b7a56caa16bc213e4f9f8ed38c4d9557069527b5d5281ca"
 dependencies = [
  "bitflags 2.6.0",
  "gpu-descriptor-types",
- "hashbrown 0.14.5",
+ "hashbrown 0.15.2",
 ]
 
 [[package]]
@@ -1344,9 +1344,9 @@ checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
 [[package]]
 name = "libc"
-version = "0.2.168"
+version = "0.2.169"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5aaeb2981e0606ca11d79718f8bb01164f1d6ed75080182d3abf017e6d244b6d"
+checksum = "b5aba8db14291edd000dfcc4d620c7ebfb122c613afb886ca8803fa4e128a20a"
 
 [[package]]
 name = "libloading"
@@ -1418,6 +1418,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "matchers"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8263075bb86c5a1b1427b5ae862e8889656f126e9f77c484496e8b47cf5c5558"
+dependencies = [
+ "regex-automata 0.1.10",
+]
+
 [[package]]
 name = "memchr"
 version = "2.7.4"
@@ -1485,9 +1494,9 @@ dependencies = [
 
 [[package]]
 name = "miniz_oxide"
-version = "0.8.0"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2d80299ef12ff69b16a84bb182e3b9df68b5a91574d3d4fa6e41b65deec4df1"
+checksum = "4ffbe83022cedc1d264172192511ae958937694cd57ce297164951b8b3568394"
 dependencies = [
  "adler2",
 ]
@@ -1630,6 +1639,25 @@ dependencies = [
  "instant",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
+[[package]]
+name = "nu-ansi-term"
+version = "0.50.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4a28e057d01f97e61255210fcff094d74ed0466038633e95017f5beb68e4399"
+dependencies = [
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "num-conv"
 version = "0.1.0"
@@ -1891,9 +1919,9 @@ dependencies = [
 
 [[package]]
 name = "object"
-version = "0.36.5"
+version = "0.36.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aedf0a2d09c573ed1d8d85b30c119153926a2b36dce0ab28322c09a117a4683e"
+checksum = "62948e14d923ea95ea2c7c86c71013138b66525b86bdc08d2dcc262bdb497b87"
 dependencies = [
  "crc32fast",
  "flate2",
@@ -1922,6 +1950,12 @@ dependencies = [
  "sdl2-sys",
 ]
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "owned_ttf_parser"
 version = "0.25.0"
@@ -2117,9 +2151,9 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.37"
+version = "1.0.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
+checksum = "0e4dccaaaf89514f546c693ddc140f729f958c247918a13380cccc6078391acc"
 dependencies = [
  "proc-macro2",
 ]
@@ -2233,8 +2267,17 @@ checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-automata",
- "regex-syntax",
+ "regex-automata 0.4.9",
+ "regex-syntax 0.8.5",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
+dependencies = [
+ "regex-syntax 0.6.29",
 ]
 
 [[package]]
@@ -2245,9 +2288,15 @@ checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-syntax",
+ "regex-syntax 0.8.5",
 ]
 
+[[package]]
+name = "regex-syntax"
+version = "0.6.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
+
 [[package]]
 name = "regex-syntax"
 version = "0.8.5"
@@ -2308,6 +2357,9 @@ dependencies = [
  "spirt",
  "spirv-tools",
  "thorin-dwp",
+ "tracing",
+ "tracing-subscriber",
+ "tracing-tree",
 ]
 
 [[package]]
@@ -2357,9 +2409,9 @@ dependencies = [
 
 [[package]]
 name = "rustversion"
-version = "1.0.18"
+version = "1.0.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e819f2bc632f285be6d7cd36e25940d45b2391dd6d9b939e79de557f7014248"
+checksum = "f7c45b9784283f1b2e7fb61b42047c2fd678ef0960d4f6f1eba131594cc369d4"
 
 [[package]]
 name = "ruzstd"
@@ -2445,24 +2497,24 @@ dependencies = [
 
 [[package]]
 name = "semver"
-version = "1.0.23"
+version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61697e0a1c7e512e84a621326239844a24d8207b4669b41bc18b32ea5cbf988b"
+checksum = "3cb6eb87a131f756572d7fb904f6e7b68633f09cca868c5df1c4b8d1a694bbba"
 
 [[package]]
 name = "serde"
-version = "1.0.216"
+version = "1.0.217"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b9781016e935a97e8beecf0c933758c97a5520d32930e460142b4cd80c6338e"
+checksum = "02fc4265df13d6fa1d00ecff087228cc0a2b5f3c0e87e258d8b94a156e984c70"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.216"
+version = "1.0.217"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "46f859dbbf73865c6627ed570e78961cd3ac92407a2d117204c49232485da55e"
+checksum = "5a9bf7cf98d04a2b28aead066b7496853d4779c9cc183c440dbac457641e19a0"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2471,9 +2523,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.133"
+version = "1.0.134"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7fceb2473b9166b2294ef05efcb65a3db80803f0b03ef86a5fc88a2b85ee377"
+checksum = "d00f4175c42ee48b15416f6193a959ba3a0d67fc699a0db9ad12df9f83991c7d"
 dependencies = [
  "itoa",
  "memchr",
@@ -2481,6 +2533,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "shared"
 version = "0.0.0"
@@ -2709,9 +2770,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.90"
+version = "2.0.94"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "919d3b74a5dd0ccd15aeb8f93e7006bd9e14c295087c9896a110f490752bcf31"
+checksum = "987bc0be1cdea8b10216bd06e2ca407d40b9543468fafd3ddfb02f36e77f71f3"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2796,6 +2857,16 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b9ef9bad013ada3808854ceac7b46812a6465ba368859a37e2100283d2d719c"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+]
+
 [[package]]
 name = "time"
 version = "0.3.37"
@@ -2898,6 +2969,61 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e672c95779cf947c5311f83787af4fa8fffd12fb27e4993211a84bdfd9610f9c"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-serde"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "704b1aeb7be0d0a84fc9828cae51dab5970fee5088f83d1dd7ee6f6246fc6ff1"
+dependencies = [
+ "serde",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8189decb5ac0fa7bc8b96b7cb9b2701d60d48805aca84a238004d665fcc4008"
+dependencies = [
+ "matchers",
+ "nu-ansi-term 0.46.0",
+ "once_cell",
+ "regex",
+ "serde",
+ "serde_json",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
+ "tracing-serde",
+]
+
+[[package]]
+name = "tracing-tree"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b56c62d2c80033cb36fae448730a2f2ef99410fe3ecbffc916681a32f6807dbe"
+dependencies = [
+ "nu-ansi-term 0.50.1",
+ "tracing-core",
+ "tracing-log",
+ "tracing-subscriber",
 ]
 
 [[package]]
@@ -2946,6 +3072,12 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
 [[package]]
 name = "version-compare"
 version = "0.1.1"
@@ -3043,9 +3175,9 @@ checksum = "943aab3fdaaa029a6e0271b35ea10b72b943135afe9bffca82384098ad0e06a6"
 
 [[package]]
 name = "wasmparser"
-version = "0.218.0"
+version = "0.222.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b09e46c7fceceaa72b2dd1a8a137ea7fd8f93dfaa69806010a709918e496c5dc"
+checksum = "4adf50fde1b1a49c1add6a80d47aea500c88db70551805853aa8b88f3ea27ab5"
 dependencies = [
  "bitflags 2.6.0",
 ]
@@ -3661,9 +3793,9 @@ checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
 [[package]]
 name = "winit"
-version = "0.30.5"
+version = "0.30.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0be9e76a1f1077e04a411f0b989cbd3c93339e1771cb41e71ac4aee95bfd2c67"
+checksum = "dba50bc8ef4b6f1a75c9274fb95aa9a8f63fbc66c56f391bd85cf68d51e7b1a3"
 dependencies = [
  "ahash",
  "android-activity",
@@ -3714,9 +3846,9 @@ dependencies = [
 
 [[package]]
 name = "winnow"
-version = "0.6.20"
+version = "0.6.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "36c1fec1a2bb5866f07c25f68c26e565c4c200aebb96d7e55710c19d3e8ac49b"
+checksum = "e6f5bb5257f2407a5425c6e749bfd9692192a73e70a6060516ac04f889087d68"
 dependencies = [
  "memchr",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 4fe02da511..d733803889 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -46,6 +46,8 @@ spirv-std-macros = { path = "./crates/spirv-std/macros", version = "=0.9.0" }
 spirv-tools = { version = "0.10", default-features = false }
 rustc_codegen_spirv = { path = "./crates/rustc_codegen_spirv", version = "=0.9.0", default-features = false }
 rustc_codegen_spirv-types = { path = "./crates/rustc_codegen_spirv-types", version = "=0.9.0" }
+tracing = "0.1"
+tracing-subscriber = { version = "0.3.3", features = ["env-filter", "json"] }
 
 # External dependencies that need to be mentioned more than once.
 num-traits = { version = "0.2.15", default-features = false }
diff --git a/crates/rustc_codegen_spirv/Cargo.toml b/crates/rustc_codegen_spirv/Cargo.toml
index 0fdca9a155..a76d9fb9d1 100644
--- a/crates/rustc_codegen_spirv/Cargo.toml
+++ b/crates/rustc_codegen_spirv/Cargo.toml
@@ -57,6 +57,9 @@ spirt = "0.4.0"
 spirv-tools.workspace = true
 lazy_static = "1.4.0"
 itertools = "0.10.5"
+tracing.workspace = true
+tracing-subscriber.workspace = true
+tracing-tree = "0.3.0"
 
 [dev-dependencies]
 pipe = "0.4"
diff --git a/crates/rustc_codegen_spirv/src/lib.rs b/crates/rustc_codegen_spirv/src/lib.rs
index f5ab65665d..9f20513fa4 100644
--- a/crates/rustc_codegen_spirv/src/lib.rs
+++ b/crates/rustc_codegen_spirv/src/lib.rs
@@ -247,6 +247,11 @@ impl ThinBufferMethods for SpirvThinBuffer {
 struct SpirvCodegenBackend;
 
 impl CodegenBackend for SpirvCodegenBackend {
+    fn init(&self, sess: &Session) {
+        // Set up logging/tracing. See https://github.com/Rust-GPU/rust-gpu/issues/192.
+        init_logging(sess);
+    }
+
     fn locale_resource(&self) -> &'static str {
         rustc_errors::DEFAULT_LOCALE_RESOURCE
     }
@@ -551,3 +556,72 @@ pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
 
     Box::new(SpirvCodegenBackend)
 }
+
+// Set up logging/tracing. See https://github.com/Rust-GPU/rust-gpu/issues/192.
+fn init_logging(sess: &Session) {
+    use std::env::{self, VarError};
+    use std::io::{self, IsTerminal};
+    use tracing_subscriber::layer::SubscriberExt;
+
+    // Set up the default subscriber with optional filtering.
+    let filter = tracing_subscriber::EnvFilter::from_env("RUSTGPU_LOG");
+    #[cfg(not(rustc_codegen_spirv_disable_pqp_cg_ssa))]
+    let filter = filter.add_directive("rustc_codegen_spirv::maybe_pqp_cg_ssa=off".parse().unwrap());
+    let subscriber = tracing_subscriber::Registry::default().with(filter);
+
+    #[derive(Debug, Default)]
+    enum OutputFormat {
+        #[default]
+        Tree,
+        Flat,
+        Json,
+    }
+
+    let output_format = match env::var("RUSTGPU_LOG_FORMAT").as_deref() {
+        Ok("tree") | Err(VarError::NotPresent) => OutputFormat::Tree,
+        Ok("flat") => OutputFormat::Flat,
+        Ok("json") => OutputFormat::Json,
+        Ok(value) => sess.dcx().fatal(format!(
+            "invalid output format value '{value}': expected one of tree, flat, or json",
+        )),
+        Err(VarError::NotUnicode(value)) => sess.dcx().fatal(format!(
+            "invalid output format value '{}': expected one of tree, flat, or json",
+            value.to_string_lossy()
+        )),
+    };
+
+    let subscriber: Box<dyn tracing::Subscriber + Send + Sync> = match output_format {
+        OutputFormat::Tree => {
+            // TODO(@LegNeato): Query dcx color support when rustc exposes it.
+            let color_logs = match env::var("RUSTGPU_LOG_COLOR").as_deref() {
+                Ok("always") => true,
+                Ok("never") => false,
+                Ok("auto") | Err(VarError::NotPresent) => io::stderr().is_terminal(),
+                Ok(value) => sess.dcx().fatal(format!(
+                    "invalid log color value '{value}': expected one of always, never, or auto",
+                )),
+                Err(VarError::NotUnicode(value)) => sess.dcx().fatal(format!(
+                    "invalid log color value '{}': expected one of always, never, or auto",
+                    value.to_string_lossy()
+                )),
+            };
+
+            let tree_layer = tracing_tree::HierarchicalLayer::default()
+                .with_writer(io::stderr)
+                .with_ansi(color_logs)
+                .with_targets(true)
+                .with_wraparound(10)
+                .with_verbose_exit(true)
+                .with_verbose_entry(true)
+                .with_indent_amount(2);
+
+            #[cfg(debug_assertions)]
+            let tree_layer = tree_layer.with_thread_ids(true).with_thread_names(true);
+
+            Box::new(subscriber.with(tree_layer))
+        }
+        OutputFormat::Flat => Box::new(subscriber),
+        OutputFormat::Json => Box::new(subscriber.with(tracing_subscriber::fmt::layer().json())),
+    };
+    tracing::subscriber::set_global_default(subscriber).unwrap();
+}
diff --git a/deny.toml b/deny.toml
index 0dac316c90..96c376090f 100644
--- a/deny.toml
+++ b/deny.toml
@@ -56,6 +56,8 @@ skip-tree = [
     { name = "minifb", version = "=0.25.0", depth = 3 },
     # HACK(eddyb) `num_cpus` (a `tester` dep) uses older `hermit-abi`.
     { name = "num_cpus", version = "=1.16.0", depth = 2 },
+    # HACK(LegNeato) `tracing-tree` uses newer dependencies of `tracing`.
+    { name = "tracing-tree", version = "=0.3.1" },
 ]