f2e8e2faff
Currently, chain functions are free to set up a stack pointer if they need one, and they assume they can start at scratch offset 0. This is not correct if CWSR and dynamic VGPRs are both enabled, since in that case we need to reserve an area at offset 0 for the trap handler, but only when running on a compute queue (which we determine at runtime). Rather than duplicate in every chain function the code sequence for determining if/how much scratch space needs to be reserved, this patch changes the ABI of chain functions so that they receive a stack pointer from their caller. Since chain functions can no longer use plain offsets to access their own stack, we'll also need to allocate a frame pointer more often (and sometimes also a base pointer). For simplicity, we use the same registers that `amdgpu_gfx` functions do (s32, s33, s34). This may change in the future. Chain functions never return to their caller and thus don't need to preserve the frame or base pointer. Another consequence is that now we might need to realign the stack in some cases (since it no longer starts at the infinitely aligned 0).
138 lines
4.1 KiB
C++
138 lines
4.1 KiB
C++
//===-- AMDGPUMachineFunctionInfo.h -------------------------------*- C++ -*-=//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPUMACHINEFUNCTION_H
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#define LLVM_LIB_TARGET_AMDGPU_AMDGPUMACHINEFUNCTION_H
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#include "Utils/AMDGPUBaseInfo.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalValue.h"
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#include "llvm/IR/GlobalVariable.h"
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namespace llvm {
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class AMDGPUSubtarget;
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class AMDGPUMachineFunction : public MachineFunctionInfo {
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/// A map to keep track of local memory objects and their offsets within the
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/// local memory space.
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SmallDenseMap<const GlobalValue *, unsigned, 4> LocalMemoryObjects;
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protected:
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uint64_t ExplicitKernArgSize = 0; // Cache for this.
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Align MaxKernArgAlign; // Cache for this.
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/// Number of bytes in the LDS that are being used.
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uint32_t LDSSize = 0;
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uint32_t GDSSize = 0;
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/// Number of bytes in the LDS allocated statically. This field is only used
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/// in the instruction selector and not part of the machine function info.
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uint32_t StaticLDSSize = 0;
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uint32_t StaticGDSSize = 0;
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/// Align for dynamic shared memory if any. Dynamic shared memory is
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/// allocated directly after the static one, i.e., LDSSize. Need to pad
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/// LDSSize to ensure that dynamic one is aligned accordingly.
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/// The maximal alignment is updated during IR translation or lowering
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/// stages.
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Align DynLDSAlign;
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// Flag to check dynamic LDS usage by kernel.
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bool UsesDynamicLDS = false;
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uint32_t NumNamedBarriers = 0;
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// Kernels + shaders. i.e. functions called by the hardware and not called
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// by other functions.
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bool IsEntryFunction = false;
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// Entry points called by other functions instead of directly by the hardware.
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bool IsModuleEntryFunction = false;
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// Functions with the amdgpu_cs_chain or amdgpu_cs_chain_preserve CC.
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bool IsChainFunction = false;
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// Function may be memory bound.
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bool MemoryBound = false;
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// Kernel may need limited waves per EU for better performance.
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bool WaveLimiter = false;
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bool HasInitWholeWave = false;
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public:
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AMDGPUMachineFunction(const Function &F, const AMDGPUSubtarget &ST);
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uint64_t getExplicitKernArgSize() const {
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return ExplicitKernArgSize;
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}
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Align getMaxKernArgAlign() const { return MaxKernArgAlign; }
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uint32_t getLDSSize() const {
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return LDSSize;
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}
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uint32_t getGDSSize() const {
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return GDSSize;
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}
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void recordNumNamedBarriers(uint32_t GVAddr, unsigned BarCnt) {
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NumNamedBarriers =
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std::max(NumNamedBarriers, ((GVAddr & 0x1ff) >> 4) + BarCnt - 1);
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}
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uint32_t getNumNamedBarriers() const { return NumNamedBarriers; }
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bool isEntryFunction() const {
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return IsEntryFunction;
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}
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bool isModuleEntryFunction() const { return IsModuleEntryFunction; }
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bool isChainFunction() const { return IsChainFunction; }
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// The stack is empty upon entry to this function.
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bool isBottomOfStack() const { return isEntryFunction(); }
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bool isMemoryBound() const {
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return MemoryBound;
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}
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bool needsWaveLimiter() const {
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return WaveLimiter;
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}
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bool hasInitWholeWave() const { return HasInitWholeWave; }
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void setInitWholeWave() { HasInitWholeWave = true; }
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unsigned allocateLDSGlobal(const DataLayout &DL, const GlobalVariable &GV) {
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return allocateLDSGlobal(DL, GV, DynLDSAlign);
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}
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unsigned allocateLDSGlobal(const DataLayout &DL, const GlobalVariable &GV,
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Align Trailing);
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static std::optional<uint32_t> getLDSKernelIdMetadata(const Function &F);
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static std::optional<uint32_t> getLDSAbsoluteAddress(const GlobalValue &GV);
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Align getDynLDSAlign() const { return DynLDSAlign; }
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void setDynLDSAlign(const Function &F, const GlobalVariable &GV);
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void setUsesDynamicLDS(bool DynLDS);
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bool isDynamicLDSUsed() const;
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};
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}
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#endif
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