AMDGPU: Write LDS objects out as global symbols in code generation
Summary:
The symbols use the processor-specific SHN_AMDGPU_LDS section index
introduced with a previous change. The linker is then expected to resolve
relocations, which are also emitted.
Initially disabled for HSA and PAL environments until they have caught up
in terms of linker and runtime loader.
Some notes:
- The llvm.amdgcn.groupstaticsize intrinsics can no longer be lowered
to a constant at compile times, which means some tests can no longer
be applied.
The current "solution" is a terrible hack, but the intrinsic isn't
used by Mesa, so we can keep it for now.
- We no longer know the full LDS size per kernel at compile time, which
means that we can no longer generate a relevant error message at
compile time. It would be possible to add a check for the size of
individual variables, but ultimately the linker will have to perform
the final check.
Change-Id: If66dbf33fccfbf3609aefefa2558ac0850d42275
Reviewers: arsenm, rampitec, t-tye, b-sumner, jsjodin
Subscribers: qcolombet, kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61494
llvm-svn: 364297
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
index 5578251..bad5670 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
@@ -298,10 +298,37 @@
}
void AMDGPUAsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
+ if (GV->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS) {
+ if (GV->hasInitializer() && !isa<UndefValue>(GV->getInitializer())) {
+ OutContext.reportError({},
+ Twine(GV->getName()) +
+ ": unsupported initializer for address space");
+ return;
+ }
- // Group segment variables aren't emitted in HSA.
- if (AMDGPU::isGroupSegment(GV))
+ // LDS variables aren't emitted in HSA or PAL yet.
+ const Triple::OSType OS = TM.getTargetTriple().getOS();
+ if (OS == Triple::AMDHSA || OS == Triple::AMDPAL)
+ return;
+
+ MCSymbol *GVSym = getSymbol(GV);
+
+ GVSym->redefineIfPossible();
+ if (GVSym->isDefined() || GVSym->isVariable())
+ report_fatal_error("symbol '" + Twine(GVSym->getName()) +
+ "' is already defined");
+
+ const DataLayout &DL = GV->getParent()->getDataLayout();
+ uint64_t Size = DL.getTypeAllocSize(GV->getValueType());
+ unsigned Align = GV->getAlignment();
+ if (!Align)
+ Align = 4;
+
+ EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
+ EmitLinkage(GV, GVSym);
+ getTargetStreamer()->emitAMDGPULDS(GVSym, Size, Align);
return;
+ }
AsmPrinter::EmitGlobalVariable(GV);
}