Rework command-line options handling for entry points and targets (#697)

* Rework command-line options handling for entry points and targets

Overview:

* The biggest functionality change is that the implicit ordering constraints when multiple `-entry` options are reversed: any `-stage` option affects the `-entry` to its *left* instead of to its *right* as it used to. This is technically a breaking change, but I expect most users aren't using this feature.

* The options parsing tries to handle profile versions and stages as distinct data (rather than using the combined `Profile` type all over), and treats a `-profile` option that specifies both a profile version and a stage (e.g., `-profile ps_5_0`) as if it were sugar for both a `-profile` and a `-stage` (e.g., `-profile sm_5_0 -stage fragment`).

* We now technically handle multiple `-target` options in one invocation of `-slangc`, but do not advertise that fact in the documentation because it might be confusing for users. Similar to the relationship between `-stage` and `-entry`, any `-profile` option affects the most recent `-target` option unless there is only one `-target`.

* The logic for associating `-o` options with corresponding entry points and targets has been beefed up. The rule is that a `-o` option for a compiled kernel binds to the entry point to its left, unless there is only one entry point (just like for `-stage`). The associated target for a `-o` option is found via a search, however, because otherwise it would be impossible to specify `-o` options for both SPIR-V and DXIL in one pass.

* The handling of output paths for entry points in the internal compiler structures was changed, because previously it could only handle one output path per entry point (even when there are multiple targets). The new logic builds up a per-target mapping from an entry point to its desired output path (if any).

Details:

* Support for formatting profile versions, stages, and compile targets (formats) was added to diagnostic printing, so that we can make better error messages. This is fairly ad hoc, and it would be nice to have all of the string<->enum stuff be more data-driven throughout the codebase.

* Test cases were added for (almost) all of the error conditions in the current options validation. The main one that is missing is around specifying an `-entry` option before any source file when compiling multiple files. This is because the test runner is putting the source file name first on the command line automatically, so we can't reproduce that case.

* Several reflection-related tests now reflect entry points where they didn't before, because the logic for detecting when to infer a default `main` entry point have been made more loose

* On the dxc path, beefed up the handling of mapping from Slang `Profile`s to the coresponding string to use when invoking dxc.

* A bunch of tests cases were in violation of the newly imposed rules, so those needed to be cleaned up.

* There were also a bunch of test cases that had accidentally gotten "disabled" at some point because there were comparing output from `slangc` both with and without a `-pass-through` option, but that meant that any errors in command-line parsing produced the *same* error output in both the Slang and pass-through cases. This change updates `slang-test` to always expect a successful run for these tests, and then manually updates or disables the various test cases that are affected.

* When merging the updated test for matrix layout mode, I found that the new command-line logic was failing to propagate a matrix layout mode passed to `render-test` into the compiler. This was because the `-matrix-layout*` options were implemented as per-target, but the target was being set by API while the option came in via command line (passed through the API). It seems like we want matrix layout mode to be a global option anyway (rather than per-target), so I made that change here.

* Add missing expected output files

* A 64-bit fix

* Remove commented-out code noted in review

3 files changed, 16 insertions, 11 deletions

diff --git a/tests/rewriter/error0.hlsl b/tests/rewriter/error0.hlsl
index e42dec23e..d3deb2953 100644
--- a/tests/rewriter/error0.hlsl
+++ b/tests/rewriter/error0.hlsl
@@ -1,4 +1,7 @@
-//TEST(smoke):COMPARE_HLSL: -no-checking -target dxbc-assembly -profile ps_4_0 -entry main
+// Disbaled because Slang does semantic checks now, not the downstream compiler.
+
+//TEST_IGNORE_FILE
+//TEST(smoke):COMPARE_HLSL: -profile ps_4_0 -entry main
 
 // We need to confirm that when there is an error in
 // the input code, we allow the downstream compiler
diff --git a/tests/rewriter/gh-160.hlsl b/tests/rewriter/gh-160.hlsl
index 46ef6a92c..b412a75a1 100644
--- a/tests/rewriter/gh-160.hlsl
+++ b/tests/rewriter/gh-160.hlsl
@@ -1,4 +1,6 @@
-//TEST:COMPARE_HLSL: -no-checking -target dxbc-assembly -profile ps_4_0 -entry main
+// Disabled because Slang should give the error, not downstream compiler
+//TEST_IGNORE_FILE
+//TEST:COMPARE_HLSL: -profile ps_4_0 -entry main
 
 #ifdef __SLANG__
 __import gh_160;
diff --git a/tests/rewriter/type-splitting.hlsl b/tests/rewriter/type-splitting.hlsl
index b3cad1ce0..0826cbf21 100644
--- a/tests/rewriter/type-splitting.hlsl
+++ b/tests/rewriter/type-splitting.hlsl
@@ -1,4 +1,4 @@
-//TEST:COMPARE_HLSL: -split-mixed-types -no-checking -target dxbc-assembly -profile ps_4_0 -entry main
+//TEST:COMPARE_HLSL: -profile ps_4_0 -entry main
 
 // Confirm that the `-split-mixed-types` flag works.
 
@@ -37,22 +37,22 @@ float4 main() : SV_Target
 // - Fields of resource type get hoisted out of variable declarations
 //
 
-struct Foo
+struct Foo_0
 {
-	float2 u;
+	float2 u_0;
 };
 
-cbuffer C
+cbuffer C_0
 {
-	Foo foo;
+	Foo_0 foo_0;
 }
 
-Texture2D    SLANG_parameterGroup_C_foo_t;
-SamplerState SLANG_parameterGroup_C_foo_s;
+Texture2D    C_foo_t_0;
+SamplerState C_foo_s_0;
 
-float4 main() : SV_Target
+float4 main() : SV_TARGET
 {
-	return SLANG_parameterGroup_C_foo_t.Sample(SLANG_parameterGroup_C_foo_s, foo.u);	
+	return C_foo_t_0.Sample(C_foo_s_0, foo_0.u_0);	
 }
 
 #endif