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llvm-project/llvm/test/Transforms/LowerBitSets/simple.ll

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Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; RUN: opt -S -lowerbitsets < %s | FileCheck %s
; RUN: opt -S -O3 < %s | FileCheck -check-prefix=CHECK-NODISCARD %s
target datalayout = "e-p:32:32"
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[G:@[^ ]*]] = private constant { i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] } { i32 1, [0 x i8] zeroinitializer, [63 x i32] zeroinitializer, [4 x i8] zeroinitializer, i32 3, [0 x i8] zeroinitializer, [2 x i32] [i32 4, i32 5] }
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
@a = constant i32 1
@b = constant [63 x i32] zeroinitializer
@c = constant i32 3
@d = constant [2 x i32] [i32 4, i32 5]
LowerBitSets: Use byte arrays instead of bit sets to represent in-memory bit sets. By loading from indexed offsets into a byte array and applying a mask, a program can test bits from the bit set with a relatively short instruction sequence. For example, suppose we have 15 bit sets to lay out: A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits), F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits), L (4 bits), M (3 bits), N (2 bits), O (1 bit) These bits can be laid out in a 16-byte array like this: Byte Offset 0123456789ABCDEF Bit 7 HHHHHHHHHIIIIIII 6 GGGGGGGGGGJJJJJJ 5 FFFFFFFFFFFKKKKK 4 EEEEEEEEEEEELLLL 3 DDDDDDDDDDDDDMMM 2 CCCCCCCCCCCCCCNN 1 BBBBBBBBBBBBBBBO 0 AAAAAAAAAAAAAAAA For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done in 1-2 machine instructions on x86, or 4-6 instructions on ARM. This uses the LPT multiprocessor scheduling algorithm to lay out the bits efficiently. Saves ~450KB of instructions in a recent build of Chromium. Differential Revision: http://reviews.llvm.org/D7954 llvm-svn: 231043
2015-03-03 08:49:28 +08:00
; CHECK: [[BA:@[^ ]*]] = private constant [68 x i8] c"\03\01\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\02\00\01"
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; Offset 0, 4 byte alignment
!0 = !{!"bitset1", i32* @a, i32 0}
; CHECK-NODISCARD-DAG: !{!"bitset1", i32* @a, i32 0}
!1 = !{!"bitset1", [63 x i32]* @b, i32 0}
; CHECK-NODISCARD-DAG: !{!"bitset1", [63 x i32]* @b, i32 0}
!2 = !{!"bitset1", [2 x i32]* @d, i32 4}
; CHECK-NODISCARD-DAG: !{!"bitset1", [2 x i32]* @d, i32 4}
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; Offset 4, 256 byte alignment
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
!3 = !{!"bitset2", [63 x i32]* @b, i32 0}
; CHECK-NODISCARD-DAG: !{!"bitset2", [63 x i32]* @b, i32 0}
!4 = !{!"bitset2", i32* @c, i32 0}
; CHECK-NODISCARD-DAG: !{!"bitset2", i32* @c, i32 0}
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; Offset 0, 4 byte alignment
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
!5 = !{!"bitset3", i32* @a, i32 0}
; CHECK-NODISCARD-DAG: !{!"bitset3", i32* @a, i32 0}
!6 = !{!"bitset3", i32* @c, i32 0}
; CHECK-NODISCARD-DAG: !{!"bitset3", i32* @c, i32 0}
; Entries whose second operand is null (the result of a global being DCE'd)
; should be ignored.
!7 = !{!"bitset2", null, i32 0}
!llvm.bitsets = !{ !0, !1, !2, !3, !4, !5, !6, !7 }
[opaque pointer type] Add textual IR support for explicit type parameter to gep operator Similar to gep (r230786) and load (r230794) changes. Similar migration script can be used to update test cases, which successfully migrated all of LLVM and Polly, but about 4 test cases needed manually changes in Clang. (this script will read the contents of stdin and massage it into stdout - wrap it in the 'apply.sh' script shown in previous commits + xargs to apply it over a large set of test cases) import fileinput import sys import re rep = re.compile(r"(getelementptr(?:\s+inbounds)?\s*\()((<\d*\s+x\s+)?([^@]*?)(|\s*addrspace\(\d+\))\s*\*(?(3)>)\s*)(?=$|%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|zeroinitializer|<|\[\[[a-zA-Z]|\{\{)", re.MULTILINE | re.DOTALL) def conv(match): line = match.group(1) line += match.group(4) line += ", " line += match.group(2) return line line = sys.stdin.read() off = 0 for match in re.finditer(rep, line): sys.stdout.write(line[off:match.start()]) sys.stdout.write(conv(match)) off = match.end() sys.stdout.write(line[off:]) llvm-svn: 232184
2015-03-14 02:20:45 +08:00
; CHECK: @a = alias getelementptr inbounds ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }, { i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]], i32 0, i32 0)
; CHECK: @b = alias getelementptr inbounds ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }, { i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]], i32 0, i32 2)
; CHECK: @c = alias getelementptr inbounds ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }, { i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]], i32 0, i32 4)
; CHECK: @d = alias getelementptr inbounds ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }, { i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]], i32 0, i32 6)
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
[opaque pointer type] Add textual IR support for explicit type parameter to gep operator Similar to gep (r230786) and load (r230794) changes. Similar migration script can be used to update test cases, which successfully migrated all of LLVM and Polly, but about 4 test cases needed manually changes in Clang. (this script will read the contents of stdin and massage it into stdout - wrap it in the 'apply.sh' script shown in previous commits + xargs to apply it over a large set of test cases) import fileinput import sys import re rep = re.compile(r"(getelementptr(?:\s+inbounds)?\s*\()((<\d*\s+x\s+)?([^@]*?)(|\s*addrspace\(\d+\))\s*\*(?(3)>)\s*)(?=$|%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|zeroinitializer|<|\[\[[a-zA-Z]|\{\{)", re.MULTILINE | re.DOTALL) def conv(match): line = match.group(1) line += match.group(4) line += ", " line += match.group(2) return line line = sys.stdin.read() off = 0 for match in re.finditer(rep, line): sys.stdout.write(line[off:match.start()]) sys.stdout.write(conv(match)) off = match.end() sys.stdout.write(line[off:]) llvm-svn: 232184
2015-03-14 02:20:45 +08:00
; CHECK: @bits = private alias getelementptr inbounds ([68 x i8], [68 x i8]* [[BA]], i32 0, i32 0)
; CHECK: @bits1 = private alias getelementptr inbounds ([68 x i8], [68 x i8]* [[BA]], i32 0, i32 0)
LowerBitSets: Use byte arrays instead of bit sets to represent in-memory bit sets. By loading from indexed offsets into a byte array and applying a mask, a program can test bits from the bit set with a relatively short instruction sequence. For example, suppose we have 15 bit sets to lay out: A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits), F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits), L (4 bits), M (3 bits), N (2 bits), O (1 bit) These bits can be laid out in a 16-byte array like this: Byte Offset 0123456789ABCDEF Bit 7 HHHHHHHHHIIIIIII 6 GGGGGGGGGGJJJJJJ 5 FFFFFFFFFFFKKKKK 4 EEEEEEEEEEEELLLL 3 DDDDDDDDDDDDDMMM 2 CCCCCCCCCCCCCCNN 1 BBBBBBBBBBBBBBBO 0 AAAAAAAAAAAAAAAA For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done in 1-2 machine instructions on x86, or 4-6 instructions on ARM. This uses the LPT multiprocessor scheduling algorithm to lay out the bits efficiently. Saves ~450KB of instructions in a recent build of Chromium. Differential Revision: http://reviews.llvm.org/D7954 llvm-svn: 231043
2015-03-03 08:49:28 +08:00
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
declare i1 @llvm.bitset.test(i8* %ptr, metadata %bitset) nounwind readnone
; CHECK: @foo(i32* [[A0:%[^ ]*]])
define i1 @foo(i32* %p) {
; CHECK-NOT: llvm.bitset.test
; CHECK: [[R0:%[^ ]*]] = bitcast i32* [[A0]] to i8*
%pi8 = bitcast i32* %p to i8*
; CHECK: [[R1:%[^ ]*]] = ptrtoint i8* [[R0]] to i32
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[R2:%[^ ]*]] = sub i32 [[R1]], ptrtoint ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]] to i32)
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; CHECK: [[R3:%[^ ]*]] = lshr i32 [[R2]], 2
; CHECK: [[R4:%[^ ]*]] = shl i32 [[R2]], 30
; CHECK: [[R5:%[^ ]*]] = or i32 [[R3]], [[R4]]
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[R6:%[^ ]*]] = icmp ult i32 [[R5]], 68
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; CHECK: br i1 [[R6]]
LowerBitSets: Use byte arrays instead of bit sets to represent in-memory bit sets. By loading from indexed offsets into a byte array and applying a mask, a program can test bits from the bit set with a relatively short instruction sequence. For example, suppose we have 15 bit sets to lay out: A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits), F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits), L (4 bits), M (3 bits), N (2 bits), O (1 bit) These bits can be laid out in a 16-byte array like this: Byte Offset 0123456789ABCDEF Bit 7 HHHHHHHHHIIIIIII 6 GGGGGGGGGGJJJJJJ 5 FFFFFFFFFFFKKKKK 4 EEEEEEEEEEEELLLL 3 DDDDDDDDDDDDDMMM 2 CCCCCCCCCCCCCCNN 1 BBBBBBBBBBBBBBBO 0 AAAAAAAAAAAAAAAA For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done in 1-2 machine instructions on x86, or 4-6 instructions on ARM. This uses the LPT multiprocessor scheduling algorithm to lay out the bits efficiently. Saves ~450KB of instructions in a recent build of Chromium. Differential Revision: http://reviews.llvm.org/D7954 llvm-svn: 231043
2015-03-03 08:49:28 +08:00
; CHECK: [[R8:%[^ ]*]] = getelementptr i8, i8* @bits, i32 [[R5]]
; CHECK: [[R9:%[^ ]*]] = load i8, i8* [[R8]]
; CHECK: [[R10:%[^ ]*]] = and i8 [[R9]], 1
; CHECK: [[R11:%[^ ]*]] = icmp ne i8 [[R10]], 0
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
LowerBitSets: Use byte arrays instead of bit sets to represent in-memory bit sets. By loading from indexed offsets into a byte array and applying a mask, a program can test bits from the bit set with a relatively short instruction sequence. For example, suppose we have 15 bit sets to lay out: A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits), F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits), L (4 bits), M (3 bits), N (2 bits), O (1 bit) These bits can be laid out in a 16-byte array like this: Byte Offset 0123456789ABCDEF Bit 7 HHHHHHHHHIIIIIII 6 GGGGGGGGGGJJJJJJ 5 FFFFFFFFFFFKKKKK 4 EEEEEEEEEEEELLLL 3 DDDDDDDDDDDDDMMM 2 CCCCCCCCCCCCCCNN 1 BBBBBBBBBBBBBBBO 0 AAAAAAAAAAAAAAAA For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done in 1-2 machine instructions on x86, or 4-6 instructions on ARM. This uses the LPT multiprocessor scheduling algorithm to lay out the bits efficiently. Saves ~450KB of instructions in a recent build of Chromium. Differential Revision: http://reviews.llvm.org/D7954 llvm-svn: 231043
2015-03-03 08:49:28 +08:00
; CHECK: [[R16:%[^ ]*]] = phi i1 [ false, {{%[^ ]*}} ], [ [[R11]], {{%[^ ]*}} ]
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
%x = call i1 @llvm.bitset.test(i8* %pi8, metadata !"bitset1")
; CHECK-NOT: llvm.bitset.test
%y = call i1 @llvm.bitset.test(i8* %pi8, metadata !"bitset1")
; CHECK: ret i1 [[R16]]
ret i1 %x
}
; CHECK: @bar(i32* [[B0:%[^ ]*]])
define i1 @bar(i32* %p) {
; CHECK: [[S0:%[^ ]*]] = bitcast i32* [[B0]] to i8*
%pi8 = bitcast i32* %p to i8*
; CHECK: [[S1:%[^ ]*]] = ptrtoint i8* [[S0]] to i32
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[S2:%[^ ]*]] = sub i32 [[S1]], add (i32 ptrtoint ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]] to i32), i32 4)
; CHECK: [[S3:%[^ ]*]] = lshr i32 [[S2]], 8
; CHECK: [[S4:%[^ ]*]] = shl i32 [[S2]], 24
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; CHECK: [[S5:%[^ ]*]] = or i32 [[S3]], [[S4]]
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[S6:%[^ ]*]] = icmp ult i32 [[S5]], 2
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
%x = call i1 @llvm.bitset.test(i8* %pi8, metadata !"bitset2")
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: ret i1 [[S6]]
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
ret i1 %x
}
; CHECK: @baz(i32* [[C0:%[^ ]*]])
define i1 @baz(i32* %p) {
; CHECK: [[T0:%[^ ]*]] = bitcast i32* [[C0]] to i8*
%pi8 = bitcast i32* %p to i8*
; CHECK: [[T1:%[^ ]*]] = ptrtoint i8* [[T0]] to i32
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[T2:%[^ ]*]] = sub i32 [[T1]], ptrtoint ({ i32, [0 x i8], [63 x i32], [4 x i8], i32, [0 x i8], [2 x i32] }* [[G]] to i32)
; CHECK: [[T3:%[^ ]*]] = lshr i32 [[T2]], 2
; CHECK: [[T4:%[^ ]*]] = shl i32 [[T2]], 30
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; CHECK: [[T5:%[^ ]*]] = or i32 [[T3]], [[T4]]
LowerBitSets: Align referenced globals. This change aligns globals to the next highest power of 2 bytes, up to a maximum of 128. This makes it more likely that we will be able to compress bit sets with a greater alignment. In many more cases, we can now take advantage of a new optimization also introduced in this patch that removes bit set checks if the bit set is all ones. The 128 byte maximum was found to provide the best tradeoff between instruction overhead and data overhead in a recent build of Chromium. It allows us to remove ~2.4MB of instructions at the cost of ~250KB of data. Differential Revision: http://reviews.llvm.org/D7873 llvm-svn: 230540
2015-02-26 04:42:41 +08:00
; CHECK: [[T6:%[^ ]*]] = icmp ult i32 [[T5]], 66
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
; CHECK: br i1 [[T6]]
LowerBitSets: Use byte arrays instead of bit sets to represent in-memory bit sets. By loading from indexed offsets into a byte array and applying a mask, a program can test bits from the bit set with a relatively short instruction sequence. For example, suppose we have 15 bit sets to lay out: A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits), F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits), L (4 bits), M (3 bits), N (2 bits), O (1 bit) These bits can be laid out in a 16-byte array like this: Byte Offset 0123456789ABCDEF Bit 7 HHHHHHHHHIIIIIII 6 GGGGGGGGGGJJJJJJ 5 FFFFFFFFFFFKKKKK 4 EEEEEEEEEEEELLLL 3 DDDDDDDDDDDDDMMM 2 CCCCCCCCCCCCCCNN 1 BBBBBBBBBBBBBBBO 0 AAAAAAAAAAAAAAAA For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done in 1-2 machine instructions on x86, or 4-6 instructions on ARM. This uses the LPT multiprocessor scheduling algorithm to lay out the bits efficiently. Saves ~450KB of instructions in a recent build of Chromium. Differential Revision: http://reviews.llvm.org/D7954 llvm-svn: 231043
2015-03-03 08:49:28 +08:00
; CHECK: [[T8:%[^ ]*]] = getelementptr i8, i8* @bits1, i32 [[T5]]
; CHECK: [[T9:%[^ ]*]] = load i8, i8* [[T8]]
; CHECK: [[T10:%[^ ]*]] = and i8 [[T9]], 2
; CHECK: [[T11:%[^ ]*]] = icmp ne i8 [[T10]], 0
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
LowerBitSets: Use byte arrays instead of bit sets to represent in-memory bit sets. By loading from indexed offsets into a byte array and applying a mask, a program can test bits from the bit set with a relatively short instruction sequence. For example, suppose we have 15 bit sets to lay out: A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits), F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits), L (4 bits), M (3 bits), N (2 bits), O (1 bit) These bits can be laid out in a 16-byte array like this: Byte Offset 0123456789ABCDEF Bit 7 HHHHHHHHHIIIIIII 6 GGGGGGGGGGJJJJJJ 5 FFFFFFFFFFFKKKKK 4 EEEEEEEEEEEELLLL 3 DDDDDDDDDDDDDMMM 2 CCCCCCCCCCCCCCNN 1 BBBBBBBBBBBBBBBO 0 AAAAAAAAAAAAAAAA For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done in 1-2 machine instructions on x86, or 4-6 instructions on ARM. This uses the LPT multiprocessor scheduling algorithm to lay out the bits efficiently. Saves ~450KB of instructions in a recent build of Chromium. Differential Revision: http://reviews.llvm.org/D7954 llvm-svn: 231043
2015-03-03 08:49:28 +08:00
; CHECK: [[T16:%[^ ]*]] = phi i1 [ false, {{%[^ ]*}} ], [ [[T11]], {{%[^ ]*}} ]
Introduce bitset metadata format and bitset lowering pass. This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 llvm-svn: 230054
2015-02-21 04:30:47 +08:00
%x = call i1 @llvm.bitset.test(i8* %pi8, metadata !"bitset3")
; CHECK: ret i1 [[T16]]
ret i1 %x
}
; CHECK-NOT: !llvm.bitsets