[CBP] Pointer frontend changes + groupshared pointer support (#7848)

Resolves #7628
Resolves: #8197

Primary Goals:
1. Add `Access` to pointer
2. AddressSpace::GroupShared support for pointers (SPIR-V)
3. Add `__getAddress()` to replace `&`
* `&` is not updated to `require(cpu)` since slangpy uses `&`. This
means we must: (1) merge PR; (2) replace `&` with `__getAddress()`; (3)
add `require(cpu)` to `&`

Changes:
* Added to `Ptr` the `Access` generic argument & logic (for
`Access::Read`).
* Moved the generic argument `AddressSpace` from `Ptr` to the end of the
type.
* Added pointer casting support between any `Ptr` as long as the
`AddressSpace` is the same
* Disallow globallycoherent T* and coherent T*
* Disallow const T*, T const*, and const T*
* Fixed .natvis display of `ConstantValue` `ValOperandNode`
* Support generic resolution of type-casted integers
* Added `VariablePointer` emitting for spirv + other minor logic needed
for groupshared pointers

Breaking Changes:
* Anyone using the `AddressSpace` of `Ptr` will now have to account for
the `Access` argument
* we disallow various syntax paired with `Ptr` and `T*`

---------

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/tests/language-feature/pointer/pointer-casting/pointer-casting-rules.slang b/tests/language-feature/pointer/pointer-casting/pointer-casting-rules.slang
new file mode 100644
index 000000000..d0a016fe5
--- /dev/null
+++ b/tests/language-feature/pointer/pointer-casting/pointer-casting-rules.slang
@@ -0,0 +1,51 @@
+//TEST:SIMPLE(filecheck=CHECK):-stage compute -entry computeMain -target spirv
+
+// Tests pointer casting rules: Only explicit casting is allowed between pointer types.
+// All implicit conversions between pointer types should fail.
+int* processMemory;
+RWStructuredBuffer<int> output;
+
+[numthreads(1, 1, 1)]
+void computeMain(int id : SV_DispatchThreadID)
+{
+    // regular address-of
+    // CHECK-NOT: ([[# @LINE+1]]): error
+    Ptr<int, Access::ReadWrite, AddressSpace::Device> rwPtr = processMemory + id.x;
+    // copying a pointer of T* syntax
+    // CHECK-NOT: ([[# @LINE+1]]): error
+    Ptr<int, Access::ReadWrite, AddressSpace::Device> copiedPtrOfLegacySyntax = processMemory;
+    // casting to Read ptr
+    // CHECK-NOT: ([[# @LINE+1]]): error
+    Ptr<int, Access::Read> rPtr = Ptr<int, Access::Read>(processMemory + id.x);
+
+    // casting to RW ptr from a R ptr
+    // CHECK-NOT: ([[# @LINE+1]]): error
+    Ptr<int, Access::ReadWrite, AddressSpace::Device> p1 = Ptr<int, Access::ReadWrite, AddressSpace::Device>(rPtr);
+    // casting to R ptr from a RW ptr
+    // CHECK-NOT: ([[# @LINE+1]]): error
+    Ptr<int, Access::Read, AddressSpace::Device> p2 = Ptr<int, Access::Read, AddressSpace::Device>(rwPtr);
+    // casting to ptr of different type
+    // CHECK-NOT: ([[# @LINE+1]]): error
+    Ptr<float, Access::ReadWrite, AddressSpace::Device> p3 = Ptr<float, Access::ReadWrite, AddressSpace::Device>(rPtr);
+
+    // Cannot implicit cast ptr's
+    // CHECK: ([[# @LINE+1]]): error 30019
+    Ptr<float, Access::ReadWrite, AddressSpace::Device> p4 = rPtr;
+    // cannot implcitly cast between different access qualifiers
+    // CHECK: ([[# @LINE+1]]): error 30019
+    Ptr<int, Access::Read> p5 = Ptr<int, Access::ReadWrite>(processMemory + id.x);
+    // cannot implcitly cast between different access qualifiers
+    // CHECK: ([[# @LINE+1]]): error 30019
+    Ptr<int, Access::ReadWrite> p6 = Ptr<int, Access::Read>(processMemory + id.x);
+
+    // TODO: Enable this when we allow user-defined group-shared address space, Issue #8173.
+    // Cannot cast between different address spaces.
+    // CHECK: ([[# @LINE+1]]): error
+    Ptr<float, Access::ReadWrite, AddressSpace::GroupShared> p7 = Ptr<float, Access::ReadWrite, AddressSpace::GroupShared>(rwPtr);
+    // CHECK: ([[# @LINE+1]]): error
+    Ptr<float, Access::ReadWrite, AddressSpace::GroupShared> p8 = Ptr<float, Access::ReadWrite, AddressSpace::GroupShared>(p1);
+    // CHECK: ([[# @LINE+1]]): error
+    Ptr<float, Access::ReadWrite, AddressSpace::GroupShared> p9 = rwPtr;
+
+    output[id] = *rwPtr;
+}