Remove uses of global variables

There were two main places where global variables were used in the Slang implementation:

1. The "standard library" code was generated as a string at run-time, and stored in a global variable so that it could be amortized across compiles.

2. The representation of types uses some globals (well, class `static` members) to store common types (e.g., `void`) and to deal with memory lifetime for things like canonicalized types.

In each case the "simple" fix is to move the relevant state into the `Session` type that controlled their lifetime already (the `Session` destructor was already cleaning up these globals to avoid leaks).

For the standard library stuff this really was easy, but for the types it required threading through the `Session` a bit carefully.

One more case that I found: there was a function-`static` variable used to generate a unique ID for files output when dumping of intermediates is enabled (this is almost strictly a debugging option).
Rather than make this counter per-session (which would lead to different sessions on different threads clobbering the same few files), I went ahead and used an atomic in this case.

Note that the remaining case I had been worried about was any function-`static` counter that might be used in generating unique names.
It  turns out that right now the parser doesn't use such a counter (even in cases where it probably should), and the lowering pass already uses a counter local to the pass (again, whether or not this is a good idea).

This change should be a major step toward allowing an application to use Slang in multiple threads, so long as each thread uses a distinct `SlangSession`. The case of using a single session across multiple threads is harder to support, and will require more careful implementation work.

1 files changed, 0 insertions, 15 deletions

diff --git a/source/slang/slang-stdlib.h b/source/slang/slang-stdlib.h
deleted file mode 100644
index d21b1e7f1..000000000
--- a/source/slang/slang-stdlib.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#ifndef SHADER_COMPILER_STD_LIB_H
-#define SHADER_COMPILER_STD_LIB_H
-
-#include "../core/basic.h"
-
-namespace Slang
-{
-    String getCoreLibraryCode();
-    String getHLSLLibraryCode();
-    String getGLSLLibraryCode();
-
-    void finalizeShaderLibrary();
-}
-
-#endif
\ No newline at end of file