From 7b54f43fb1b123f451460edb0add218a0428fe95 Mon Sep 17 00:00:00 2001 From: Tim Foley Date: Mon, 7 Aug 2017 14:54:55 -0700 Subject: 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. --- source/slang/emit.cpp | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'source/slang/emit.cpp') diff --git a/source/slang/emit.cpp b/source/slang/emit.cpp index 5a59674f5..d2f932ebf 100644 --- a/source/slang/emit.cpp +++ b/source/slang/emit.cpp @@ -375,6 +375,11 @@ struct EmitVisitor : context(context) {} + Session* getSession() + { + return context->shared->entryPoint->compileRequest->mSession; + } + // Low-level emit logic void emitRawTextSpan(char const* textBegin, char const* textEnd) @@ -2308,9 +2313,9 @@ struct EmitVisitor emitTokenWithLocation(litExpr->token); break; } - if(type->Equals(ExpressionType::GetInt())) + if(type->Equals(getSession()->getIntType())) {} - else if(type->Equals(ExpressionType::GetUInt())) + else if(type->Equals(getSession()->getUIntType())) { suffix = "u"; } @@ -2330,9 +2335,9 @@ struct EmitVisitor emitTokenWithLocation(litExpr->token); break; } - if(type->Equals(ExpressionType::GetFloat())) + if(type->Equals(getSession()->getFloatType())) {} - else if(type->Equals(ExpressionType::getDoubleType())) + else if(type->Equals(getSession()->getDoubleType())) { suffix = "l"; } -- cgit v1.2.3