Skip to content

Commit 0d56a9f

Browse files
vtjnashvtjnash
committed
[JITLink] fix most i686 relocations to include addend
Most relocations involve adding the value at the location with a value taken from elsewhere. Most of them were hard coded instead. Assume signed, since the math is the same either way after truncation, but this seems more likely to give reasonable looking intermediate results.
1 parent f873fc3 commit 0d56a9f

File tree

7 files changed

+60
-44
lines changed

7 files changed

+60
-44
lines changed

‎llvm/include/llvm/ExecutionEngine/JITLink/i386.h‎

Lines changed: 9 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -39,12 +39,8 @@ enum EdgeKind_i386 : Edge::Kind {
3939
/// Represents a data/control flow instruction using PC-relative addressing
4040
/// to a target.
4141
///
42-
/// The fixup expression for this kind includes an implicit offset to account
43-
/// for the PC (unlike the Delta edges) so that a PCRel32 with a target
44-
/// T and addend zero is a call/branch to the start (offset zero) of T.
45-
///
4642
/// Fixup expression:
47-
/// Fixup <- Target - (Fixup + 4) + Addend : int32
43+
/// Fixup <- Target - Fixup + Addend : int32
4844
///
4945
/// Errors:
5046
/// - The result of the fixup expression must fit into an int32, otherwise
@@ -68,12 +64,8 @@ enum EdgeKind_i386 : Edge::Kind {
6864
/// Represents a data/control flow instruction using PC-relative addressing
6965
/// to a target.
7066
///
71-
/// The fixup expression for this kind includes an implicit offset to account
72-
/// for the PC (unlike the Delta edges) so that a PCRel16 with a target
73-
/// T and addend zero is a call/branch to the start (offset zero) of T.
74-
///
7567
/// Fixup expression:
76-
/// Fixup <- Target - (Fixup + 4) + Addend : int16
68+
/// Fixup <- Target - Fixup + Addend : int16
7769
///
7870
/// Errors:
7971
/// - The result of the fixup expression must fit into an int16, otherwise
@@ -86,7 +78,7 @@ enum EdgeKind_i386 : Edge::Kind {
8678
/// Delta from the fixup to the target.
8779
///
8880
/// Fixup expression:
89-
/// Fixup <- Target - Fixup + Addend : int64
81+
/// Fixup <- Target - Fixup + Addend : int32
9082
///
9183
/// Errors:
9284
/// - The result of the fixup expression must fit into an int32, otherwise
@@ -130,12 +122,8 @@ enum EdgeKind_i386 : Edge::Kind {
130122
/// Represents a PC-relative call or branch to a target. This can be used to
131123
/// identify, record, and/or patch call sites.
132124
///
133-
/// The fixup expression for this kind includes an implicit offset to account
134-
/// for the PC (unlike the Delta edges) so that a Branch32PCRel with a target
135-
/// T and addend zero is a call/branch to the start (offset zero) of T.
136-
///
137125
/// Fixup expression:
138-
/// Fixup <- Target - (Fixup + 4) + Addend : int32
126+
/// Fixup <- Target - Fixup + Addend : int32
139127
///
140128
/// Errors:
141129
/// - The result of the fixup expression must fit into an int32, otherwise
@@ -164,7 +152,7 @@ enum EdgeKind_i386 : Edge::Kind {
164152
/// target may be recorded to allow manipulation at runtime.
165153
///
166154
/// Fixup expression:
167-
/// Fixup <- Target - Fixup + Addend - 4 : int32
155+
/// Fixup <- Target - Fixup + Addend : int32
168156
///
169157
/// Errors:
170158
/// - The result of the fixup expression must fit into an int32, otherwise
@@ -180,7 +168,7 @@ enum EdgeKind_i386 : Edge::Kind {
180168
/// is within range of the fixup location.
181169
///
182170
/// Fixup expression:
183-
/// Fixup <- Target - Fixup + Addend - 4: int32
171+
/// Fixup <- Target - Fixup + Addend : int32
184172
///
185173
/// Errors:
186174
/// - The result of the fixup expression must fit into an int32, otherwise
@@ -215,8 +203,7 @@ inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E,
215203
}
216204

217205
case i386::PCRel32: {
218-
int32_t Value =
219-
E.getTarget().getAddress() - (FixupAddress + 4) + E.getAddend();
206+
int32_t Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
220207
*(little32_t *)FixupPtr = Value;
221208
break;
222209
}
@@ -231,8 +218,7 @@ inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E,
231218
}
232219

233220
case i386::PCRel16: {
234-
int32_t Value =
235-
E.getTarget().getAddress() - (FixupAddress + 4) + E.getAddend();
221+
int32_t Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
236222
if (LLVM_LIKELY(isInt<16>(Value)))
237223
*(little16_t *)FixupPtr = Value;
238224
else
@@ -257,8 +243,7 @@ inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E,
257243
case i386::BranchPCRel32:
258244
case i386::BranchPCRel32ToPtrJumpStub:
259245
case i386::BranchPCRel32ToPtrJumpStubBypassable: {
260-
int32_t Value =
261-
E.getTarget().getAddress() - (FixupAddress + 4) + E.getAddend();
246+
int32_t Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
262247
*(little32_t *)FixupPtr = Value;
263248
break;
264249
}

‎llvm/lib/ExecutionEngine/JITLink/ELF_i386.cpp‎

Lines changed: 17 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -186,15 +186,29 @@ class ELFLinkGraphBuilder_i386 : public ELFLinkGraphBuilder<ELFT> {
186186
int64_t Addend = 0;
187187

188188
switch (*Kind) {
189-
case i386::EdgeKind_i386::Delta32: {
189+
case i386::EdgeKind_i386::None:
190+
break;
191+
case i386::EdgeKind_i386::Pointer32:
192+
case i386::EdgeKind_i386::PCRel32:
193+
case i386::EdgeKind_i386::RequestGOTAndTransformToDelta32FromGOT:
194+
case i386::EdgeKind_i386::Delta32:
195+
case i386::EdgeKind_i386::Delta32FromGOT:
196+
case i386::EdgeKind_i386::BranchPCRel32:
197+
case i386::EdgeKind_i386::BranchPCRel32ToPtrJumpStub:
198+
case i386::EdgeKind_i386::BranchPCRel32ToPtrJumpStubBypassable: {
190199
const char *FixupContent = BlockToFix.getContent().data() +
191200
(FixupAddress - BlockToFix.getAddress());
192-
Addend = *(const support::ulittle32_t *)FixupContent;
201+
Addend = *(const support::little32_t *)FixupContent;
193202
break;
194203
}
195-
default:
204+
case i386::EdgeKind_i386::Pointer16:
205+
case i386::EdgeKind_i386::PCRel16: {
206+
const char *FixupContent = BlockToFix.getContent().data() +
207+
(FixupAddress - BlockToFix.getAddress());
208+
Addend = *(const support::little16_t *)FixupContent;
196209
break;
197210
}
211+
}
198212

199213
Edge::OffsetT Offset = FixupAddress - BlockToFix.getAddress();
200214
Edge GE(*Kind, Offset, *GraphSymbol, Addend);

‎llvm/test/ExecutionEngine/JITLink/i386/ELF_i386_absolute_relocations_16.s‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -22,4 +22,12 @@ main:
2222
.type bar,@function
2323
bar:
2424
retw $external_data
25-
.size bar, .-bar
25+
.size bar, .-bar
26+
27+
# jitlink-check: decode_operand(baz, 0) = external_data + 23
28+
.globl baz
29+
.align 2, 0x90
30+
.type baz,@function
31+
baz:
32+
retw $external_data+23
33+
.size baz, .-baz

‎llvm/test/ExecutionEngine/JITLink/i386/ELF_i386_absolute_relocations_32.s‎

Lines changed: 12 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -7,17 +7,25 @@
77
# Test ELF 32 bit absolute relocations
88

99
.text
10-
.globl main
10+
.globl main
1111
.p2align 4, 0x90
1212
.type main,@function
13-
main:
13+
main:
1414
retl
1515
.size main, .-main
1616

1717
# jitlink-check: decode_operand(foo, 0) = external_data
18-
.globl foo
18+
.globl foo
1919
.p2align 4, 0x90
2020
.type foo,@function
2121
foo:
2222
movl external_data, %eax
23-
.size foo, .-foo
23+
.size foo, .-foo
24+
25+
# jitlink-check: decode_operand(bar, 0) = external_data + 4000
26+
.globl bar
27+
.p2align 4, 0x90
28+
.type bar,@function
29+
bar:
30+
movl external_data + 4000, %eax
31+
.size bar, .-bar

‎llvm/test/ExecutionEngine/JITLink/i386/ELF_i386_pc_relative_relocations_32.s‎

Lines changed: 4 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -33,17 +33,18 @@ foo:
3333

3434

3535
# Tests PC relative relocation for negative offset from PC
36-
# jitlink-check: decode_operand(baz, 0) = fooz - next_pc(baz)
36+
# jitlink-check: decode_operand(baz, 0) = fooz - next_pc(baz) + 1
3737
.globl fooz
3838
.p2align 4
3939
.type fooz,@function
4040
fooz:
41+
nop
4142
retl
4243
.size fooz, .-fooz
4344

4445
.globl baz
4546
.p2align 4
4647
.type baz,@function
4748
baz:
48-
calll fooz
49-
.size baz, .-baz
49+
calll fooz+1
50+
.size baz, .-baz

‎llvm/test/ExecutionEngine/JITLink/i386/ELF_i386_small_pic_relocations_got.s‎

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -19,29 +19,29 @@ main:
1919
# Test GOT32 handling.
2020
#
2121
# We want to check both the offset to the GOT entry and its contents.
22-
# jitlink-check: decode_operand(test_got, 4) = got_addr(elf_sm_pic_reloc_got.o, named_data1) - _GLOBAL_OFFSET_TABLE_
22+
# jitlink-check: decode_operand(test_got, 4) = got_addr(elf_sm_pic_reloc_got.o, named_data1) - _GLOBAL_OFFSET_TABLE_ + 42
2323
# jitlink-check: *{4}(got_addr(elf_sm_pic_reloc_got.o, named_data1)) = named_data1
2424
#
25-
# jitlink-check: decode_operand(test_got+6, 4) = got_addr(elf_sm_pic_reloc_got.o, named_data2) - _GLOBAL_OFFSET_TABLE_
25+
# jitlink-check: decode_operand(test_got+6, 4) = got_addr(elf_sm_pic_reloc_got.o, named_data2) - _GLOBAL_OFFSET_TABLE_ + 5
2626
# jitlink-check: *{4}(got_addr(elf_sm_pic_reloc_got.o, named_data2)) = named_data2
2727

2828
.globl test_got
2929
.p2align 4, 0x90
3030
.type test_got,@function
3131
test_got:
32-
leal named_data1@GOT, %eax
33-
leal named_data2@GOT, %eax
32+
leal named_data1@GOT+42, %eax
33+
leal named_data2@GOT+5, %eax
3434
.size test_got, .-test_got
3535

3636

3737

3838
# Test GOTOFF64 handling.
39-
# jitlink-check: decode_operand(test_gotoff, 1) = named_func - _GLOBAL_OFFSET_TABLE_
39+
# jitlink-check: decode_operand(test_gotoff, 1) = named_func - _GLOBAL_OFFSET_TABLE_ + 99
4040
.globl test_gotoff
4141
.p2align 4, 0x90
4242
.type test_gotoff,@function
4343
test_gotoff:
44-
mov $named_func@GOTOFF, %eax
44+
mov $named_func@GOTOFF+99, %eax
4545
.size test_gotoff, .-test_gotoff
4646

4747

‎llvm/test/ExecutionEngine/JITLink/i386/ELF_i386_small_pic_relocations_plt.s‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -27,12 +27,12 @@ main:
2727
# for position independent code, first, as there may be future use-cases
2828
# where we would want to disable the optimization.
2929
#
30-
# jitlink-check: decode_operand(test_call_extern_plt, 0) = external_func - next_pc(test_call_extern_plt)
30+
# jitlink-check: decode_operand(test_call_extern_plt, 0) = external_func - next_pc(test_call_extern_plt) + 53
3131
# jitlink-check: *{4}(got_addr(elf_sm_pic_reloc_plt.o, external_func))= external_func
3232
.globl test_call_extern_plt
3333
.p2align 4, 0x90
3434
.type test_call_extern_plt,@function
3535
test_call_extern_plt:
36-
call external_func@plt
36+
call external_func@plt + 53
3737

38-
.size test_call_extern_plt, .-test_call_extern_plt
38+
.size test_call_extern_plt, .-test_call_extern_plt

0 commit comments

Comments
 (0)