fix up the builder so that this works as a nix expression

crates/spirv_backend_builder/Cargo.toml

@@ -6,3 +6,19 @@ edition = "2021"
 
 [dependencies]
 spirv-builder = { git = "https://github.com/EmbarkStudios/rust-gpu", features = ["use-compiled-tools"] }
+
+# these deps are to satisfy internal rustc stuff, since spirv-builder links into rustc internals (HACK).
+# these are very likely to break during rustc updates, but they should be noisy.
+# just keep filling things in here based on rustc's Cargo.lock until it's satisfied.
+# this needs to match the rustc lock file -- not just its Cargo.toml -- so we pin down to the patch level
+# /nix/store/rlcla9529bwkd7a7ryrgfz97yyxaaxgd-rust-default-1.62.0-nightly-2022-04-11/lib/rustlib/src/rust/Cargo.lock
+cc = "1.0.69, < 1.0.70"
+cfg-if = "0.1.10, < 0.1.11"
+compiler_builtins = "0.1.70, < 0.1.71"
+dlmalloc = "0.2.3, < 0.2.4"
+fortanix-sgx-abi = "0.3.3, < 0.3.4"
+getopts = "0.2.21, < 0.2.22"
+hashbrown = "0.12.0, < 0.12.1"
+hermit-abi = "0.2.0, < 0.2.1"
+libc = "0.2.121, < 0.2.122"
+unicode-width = "0.1.8, < 0.1.9"

crates/spirv_backend_builder/src/main.rs

@@ -13,7 +13,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     println!("get_shader: constructing builder");
     let builder = SpirvBuilder::new(crate_path, "spirv-unknown-vulkan1.1")
     //let builder = SpirvBuilder::new(crate_path, "spirv-unknown-spv1.3")
-        .print_metadata(MetadataPrintout::None)
+        .print_metadata(MetadataPrintout::Full)
         .capability(Capability::Int8)
         // .capability(Capability::PhysicalStorageBufferAddresses)
         // .capability(Capability::Addresses)
@@ -24,6 +24,6 @@ fn main() -> Result<(), Box<dyn Error>> {
     let initial_result = builder.build()?;
 
     let module_path = initial_result.module.unwrap_single();
-    println!("get_shader: built: {:?}", module_path);
+    println!("get_shader: built:\n{}", module_path.display());
     Ok(())
 }