[mlir][ROCDL] Construct AMDGCN ISA control variable explicitly

[fabianmcg]

This patch constructs the AMDGCN ISA control variable explicitly instead of linking against the library shipped with ROCm. This change prevents issues arising from the order in which the AMDGCN libraries are linked.

[llvmbot]

@llvm/pr-subscribers-mlir-llvm

@llvm/pr-subscribers-mlir

Author: Fabian Mora (fabianmcg)

Changes

This patch constructs the AMDGCN ISA control variable explicitly instead of linking against the library shipped with ROCm. This change prevents issues arising from the order in which the AMGCN libraries are linked.

---

Full diff: https://github.com/llvm/llvm-project/pull/98912.diff

1 Files Affected:

• (modified) mlir/lib/Target/LLVM/ROCDL/Target.cpp (+9-8)

diff --git a/mlir/lib/Target/LLVM/ROCDL/Target.cpp b/mlir/lib/Target/LLVM/ROCDL/Target.cpp
index 047d214b751f1..70d6bcd76285a 100644
--- a/mlir/lib/Target/LLVM/ROCDL/Target.cpp
+++ b/mlir/lib/Target/LLVM/ROCDL/Target.cpp
@@ -150,11 +150,6 @@ LogicalResult SerializeGPUModuleBase::appendStandardLibs(AMDGCNLibraries libs) {
     return failure();
   }
 
-  // Get the ISA version.
-  StringRef isaVersion =
-      llvm::AMDGPU::getArchNameAMDGCN(llvm::AMDGPU::parseArchAMDGCN(chip));
-  isaVersion.consume_front("gfx");
-
   // Helper function for adding a library.
   auto addLib = [&](const Twine &lib) -> bool {
     auto baseSize = path.size();
@@ -175,9 +170,7 @@ LogicalResult SerializeGPUModuleBase::appendStandardLibs(AMDGCNLibraries libs) {
   if ((any(libs & AMDGCNLibraries::Ocml) && addLib("ocml.bc")) ||
       (any(libs & AMDGCNLibraries::Ockl) && addLib("ockl.bc")) ||
       (any(libs & AMDGCNLibraries::Hip) && addLib("hip.bc")) ||
-      (any(libs & AMDGCNLibraries::OpenCL) && addLib("opencl.bc")) ||
-      (any(libs & (AMDGCNLibraries::Ocml | AMDGCNLibraries::Ockl)) &&
-       addLib("oclc_isa_version_" + isaVersion + ".bc")))
+      (any(libs & AMDGCNLibraries::OpenCL) && addLib("opencl.bc")))
     return failure();
   return success();
 }
@@ -270,6 +263,14 @@ void SerializeGPUModuleBase::addControlVariables(
   // Add ocml or ockl related control variables.
   if (any(libs & (AMDGCNLibraries::Ocml | AMDGCNLibraries::Ockl))) {
     addControlVariable("__oclc_wavefrontsize64", wave64, 8);
+
+    // Get the ISA version.
+    llvm::AMDGPU::IsaVersion isaVersion = llvm::AMDGPU::getIsaVersion(chip);
+    // Add the ISA control variable.
+    addControlVariable("__oclc_ISA_version",
+                       isaVersion.Minor + 100 * isaVersion.Stepping +
+                           1000 * isaVersion.Major,
+                       32);
     int abi = 500;
     abiVer.getAsInteger(0, abi);
     addControlVariable("__oclc_ABI_version", abi, 32);

[krzysz00]

Nice find!