1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
/*========================== begin_copyright_notice ============================
Copyright (C) 2024 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#ifndef IGCLLVM_SUPPORT_MODREF_H
#define IGCLLVM_SUPPORT_MODREF_H
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/LLVMContext.h"
#if LLVM_VERSION_MAJOR >= 16
#include "llvm/Support/ModRef.h"
// TODO: For interim LLVM revisions on major ver. 16, the following path should
// be used in between https://reviews.llvm.org/D135589 and
// https://reviews.llvm.org/D137641:
// #include "llvm/IR/ModRef.h"
#endif // LLVM_VERSION_MAJOR
#include <Probe/Assertion.h>
#include <optional>
#include <vector>
namespace IGCLLVM {
#if LLVM_VERSION_MAJOR >= 16
using ModRefInfo = llvm::ModRefInfo;
#else // LLVM_VERSION_MAJOR
/// Below is a mere copy of llvm::ModRefInfo
enum class ModRefInfo : uint8_t {
/// The access neither references nor modifies the value stored in memory.
NoModRef = 0,
/// The access may reference the value stored in memory.
Ref = 1,
/// The access may modify the value stored in memory.
Mod = 2,
/// The access may reference and may modify the value stored in memory.
ModRef = Ref | Mod,
};
#endif // LLVM_VERSION_MAJOR
/// This enumeration serves as a translation medium between pre-LLVM 16
/// (attribute-based) and LLVM 16+ (location bitmask) semantics for IR memory
/// location info. The key restriction before LLVM 16 is exclusiveness: an
/// explicit specification of a memory location implies "no access" (NoModRef)
/// for other locations.
enum class ExclusiveIRMemLoc : uint8_t {
Any = 0,
ArgMem = 1,
InaccessibleMem = 2,
InaccessibleOrArgMem = ArgMem | InaccessibleMem,
};
/// The 'detail' namespace implements the translation logic between
/// pre-LLVM 16, WrapperLLVM and LLVM 16+ layouts of attributes:
/*=============================================================================
/-----------------------------------------------------------------------------\
| Allowed memory access |
|-----------------------------------------------------------------------------|
| LLVM 16 memory effects & LLVM Wrapper | Pre-LLVM 16 attr (if any) |
|-----------------------------------------------------------------------------|
| ModRefInfo::NoModRef | ReadNone |
| ModRefInfo::Ref | ReadOnly |
| ModRefInfo::Mod | WriteOnly |
| ModRefInfo::ModRef | no location/access attrs |
\-----------------------------------------------------------------------------/
/-----------------------------------------------------------------------------\
| Memory location - LLVM 16+ |
|-----------------------------------------------------------------------------|
| LLVM Wrapper | LLVM 16 memory effects |
|-----------------------------------------------------------------------------|
| ExclusiveIRMemLoc::ArgMem | ::Location::ArgMem |
| ExclusiveIRMemLoc::InaccessibleMem | ::Location::InaccessibleMem |
| "other location" unsupported | ::Location::Other |
| ExclusiveIRMemLoc::InaccessibleOrArgMem | ArgMem + InaccessibleMem |
| ExclusiveIRMemLoc::Any | ArgMem + InaccessibleMem + Other |
|-----------------------------------------------------------------------------|
| Memory location - pre-LLVM 16 |
|-----------------------------------------------------------------------------|
| LLVM Wrapper | Pre-LLVM 16 attr (if any) |
|-----------------------------------------------------------------------------|
| ExclusiveIRMemLoc::ArgMem | ArgMemOnly |
| ExclusiveIRMemLoc::InaccessibleMem | InaccessibleMemOnly |
| "other location" unsupported | "other location" unsupported |
| ExclusiveIRMemLoc::InaccessibleOrArgMem | InaccessibleMemOrArgMemOnly |
| ExclusiveIRMemLoc::Any | no location attrs |
\-----------------------------------------------------------------------------/
=============================================================================*/
namespace detail {
using OptionalAttrKind = std::optional<llvm::Attribute::AttrKind>;
#undef IGCLLVM_SELECT_LLVM_16
// TODO: Factor out into a common preprocesser helper file
#if LLVM_VERSION_MAJOR >= 16
#define IGCLLVM_SELECT_LLVM_16(entry_ge_llvm16, entry_lt_llvm16) entry_ge_llvm16
#else // LLVM_VERSION_MAJOR
#define IGCLLVM_SELECT_LLVM_16(entry_ge_llvm16, entry_lt_llvm16) entry_lt_llvm16
#endif
using MemoryEffectsLLVMTy = IGCLLVM_SELECT_LLVM_16(llvm::MemoryEffects, OptionalAttrKind);
/// FIXME: An inheritance-based implementation would be more elegant for
/// translateMemoryEffect(...) helpers, especially if a constexpr map-like
/// structure. This would be more expressive for the translation logic (no need
/// for comment block descriptions as above). Additionally, were the map to
/// provide "vector of keys" getter capabilities (akin to C++23 std::flat_map),
/// we could then encapsulate MemoryEffects::getOverridenAttrKinds().
inline MemoryEffectsLLVMTy translateMemoryEffect(ExclusiveIRMemLoc Loc) {
if (Loc == ExclusiveIRMemLoc::ArgMem)
return IGCLLVM_SELECT_LLVM_16(llvm::MemoryEffects::argMemOnly(), llvm::Attribute::ArgMemOnly);
if (Loc == ExclusiveIRMemLoc::InaccessibleMem)
return IGCLLVM_SELECT_LLVM_16(llvm::MemoryEffects::inaccessibleMemOnly(), llvm::Attribute::InaccessibleMemOnly);
if (Loc == ExclusiveIRMemLoc::InaccessibleOrArgMem)
return IGCLLVM_SELECT_LLVM_16(llvm::MemoryEffects::inaccessibleOrArgMemOnly(),
llvm::Attribute::InaccessibleMemOrArgMemOnly);
// No restrictions
IGC_ASSERT_MESSAGE(Loc == ExclusiveIRMemLoc::Any, "Unknown ExclusiveIRMemLoc value");
return IGCLLVM_SELECT_LLVM_16(llvm::MemoryEffects::unknown(), std::nullopt);
}
inline MemoryEffectsLLVMTy translateMemoryEffect(ModRefInfo MR) {
#if LLVM_VERSION_MAJOR >= 16
return MemoryEffectsLLVMTy(MR);
#else // LLVM_VERSION_MAJOR
if (MR == ModRefInfo::NoModRef)
return llvm::Attribute::ReadNone;
if (MR == ModRefInfo::Ref)
return llvm::Attribute::ReadOnly;
if (MR == ModRefInfo::Mod)
return llvm::Attribute::WriteOnly;
// No restrictions
IGC_ASSERT_MESSAGE(MR == ModRefInfo::ModRef, "Unknown ModRefInfo value");
return {};
#endif // LLVM_VERSION_MAJOR
}
#undef IGCLLVM_SELECT_LLVM_16
} // namespace detail
/// This wrapper serves to reduce LLVM 16's MemoryEffects API to a level that
/// can be feasibly emulated through legacy attributes:
/// - it should be possible to initialize the wrapper based on static data,
/// same as with the original MemoryEffects. Therefore, no dynamic objects
/// like LLVMContext/AttributeSet are stored per instance - only accepted as
/// parameters/returned by certain methods
/// - matematical operations made available with LLVM 16 are forbidden through
/// composition. To emulate and/or semantics, we'd have to store a dynamic
/// attribute set, violating the above design and resorting to error-prone
/// AttrKind manipulations for each operation
/// - because of the "exclusive" memory location semantics, there is no
/// iteration over locations
///
/// Since LLVM 16+ MemoryEffects are only an interim descriptor used for
/// llvm::Attribute::Memory generation, any collection of contextual attributes
/// can still work as the ultimate version wrapper, dynamically queried by IGC
/// code to fetch and operate on legacy/new attribute layout (*).
///
/// NB: Static generators of custom intrinsics are the exemplary use-case for
/// this wrapper, since lightweight, context-independent info about memory
/// effects may have to be stored before the actual instantiation. Whenever
/// possible, stable high-level APIs provided by llvm::Function,
/// llvm::CallBase, etc. should actually be preferred to manual
/// MemoryEffects-based initialization of attributes.
///
/// (*) https://github.com/llvm/llvm-project/blob/release/16.x/llvm/docs/ReleaseNotes.rst#changes-to-the-llvm-ir
class MemoryEffects {
private:
ExclusiveIRMemLoc Loc;
ModRefInfo MR;
public:
constexpr MemoryEffects(ExclusiveIRMemLoc Loc, ModRefInfo MR) : Loc(Loc), MR(MR) {}
explicit constexpr MemoryEffects(ModRefInfo MR) : MemoryEffects(ExclusiveIRMemLoc::Any, MR) {}
MemoryEffects(const MemoryEffects &) = default;
MemoryEffects &operator=(const MemoryEffects &) = default;
~MemoryEffects() = default;
/// Constructs and returns an LLVMContext-dependent attribute set based on
/// the static memory effects' info.
/// For LLVM 16+, a single Memory attribute is constructed.
/// For earlier versions, up to 2 legacy attributes can be returned.
llvm::AttributeSet getAsAttributeSet(llvm::LLVMContext &C) const {
#if LLVM_VERSION_MAJOR >= 16
llvm::MemoryEffects ME = detail::translateMemoryEffect(Loc) & detail::translateMemoryEffect(MR);
auto MemAttr = llvm::Attribute::getWithMemoryEffects(C, ME);
return llvm::AttributeSet::get(C, {MemAttr});
#else // LLVM_VERSION_MAJOR
llvm::AttributeSet ResultSet;
if (auto LocAttr = detail::translateMemoryEffect(Loc))
ResultSet = ResultSet.addAttribute(C, *LocAttr);
if (auto ModRefAttr = detail::translateMemoryEffect(MR))
ResultSet = ResultSet.addAttribute(C, *ModRefAttr);
return ResultSet;
#endif // LLVM_VERSION_MAJOR
}
/// Returns an AttrBuilder based on the static memory effects' info.
llvm::AttrBuilder getAsAttrBuilder(llvm::LLVMContext &C) const { return llvm::AttrBuilder(C, getAsAttributeSet(C)); }
/// Pre-LLVM 16, returns a list of attribute kinds that would conflict with
/// underlying memory effect attributes for the given
/// IGCLLVM::MemoryEffects instance. The list is empty for LLVM 16+.
llvm::AttributeMask getOverridenAttrKinds() const {
#if LLVM_VERSION_MAJOR >= 16
// The list is empty for LLVM 16+, which corresponds to the standard LLORG
// practice of retaining old instances of Attribute::Memory and relying on
// the internal logic to merge the memory effects correctly.
return {};
#else // LLVM_VERSION_MAJOR
using AttrVector = std::vector<llvm::Attribute::AttrKind>;
AttrVector ModRefList{llvm::Attribute::ReadNone, llvm::Attribute::ReadOnly, llvm::Attribute::WriteOnly};
AttrVector LocsList{llvm::Attribute::ArgMemOnly, llvm::Attribute::InaccessibleMemOnly,
llvm::Attribute::InaccessibleMemOrArgMemOnly};
llvm::AttributeMask Result;
AttrVector ResultVec(ModRefList.begin(), ModRefList.end());
for (auto ModRefKind : ModRefList)
Result.addAttribute(ModRefKind);
if (Loc != ExclusiveIRMemLoc::Any || MR == ModRefInfo::NoModRef) {
for (auto LocKind : LocsList)
Result.addAttribute(LocKind);
}
return Result;
#endif // LLVM_VERSION_MAJOR
}
/// Define static getters matching those from LLVM 16+ llvm::MemoryEffects.
/// The logic is simple and sound enough to replicate.
static constexpr MemoryEffects unknown() { return MemoryEffects(ModRefInfo::ModRef); }
static constexpr MemoryEffects none() { return MemoryEffects(ModRefInfo::NoModRef); }
static constexpr MemoryEffects readOnly() { return MemoryEffects(ModRefInfo::Ref); }
static constexpr MemoryEffects writeOnly() { return MemoryEffects(ModRefInfo::Mod); }
static constexpr MemoryEffects argMemOnly(ModRefInfo MR = ModRefInfo::ModRef) {
return MemoryEffects(ExclusiveIRMemLoc::ArgMem, MR);
}
static constexpr MemoryEffects inaccessibleMemOnly(ModRefInfo MR = ModRefInfo::ModRef) {
return MemoryEffects(ExclusiveIRMemLoc::InaccessibleMem, MR);
}
static constexpr MemoryEffects inaccessibleOrArgMemOnly(ModRefInfo MR = ModRefInfo::ModRef) {
return MemoryEffects(ExclusiveIRMemLoc::InaccessibleOrArgMem, MR);
}
};
} // end namespace IGCLLVM
#endif // IGCLLVM_SUPPORT_MODREF_H
|
