[llvm] 4c1bc8e - [JITLink][MachO] Handle intra-block subtractor relocations.
Lang Hames via llvm-commits
llvm-commits at lists.llvm.org
Sun Dec 24 14:07:02 PST 2023
Author: Lang Hames
Date: 2023-12-24T14:06:11-08:00
New Revision: 4c1bc8e753c24df27ee8ccfc4041dd55e7c3a6ee
URL: https://github.com/llvm/llvm-project/commit/4c1bc8e753c24df27ee8ccfc4041dd55e7c3a6ee
DIFF: https://github.com/llvm/llvm-project/commit/4c1bc8e753c24df27ee8ccfc4041dd55e7c3a6ee.diff
LOG: [JITLink][MachO] Handle intra-block subtractor relocations.
Previously the JITLink MachO backends (aarch64 and x86-64) only looked at the
fixup block to determine which symbol was being fixed up. This assumption breaks
if both symbols used in the subtractor are in the same block. The fix is to
check for such cases and use the offsets of each symbol to decide which is being
fixed up.
The issue only resulted in incorrect behavior for negative-delta relocations,
so the testcases use eh-frames with explicit edges for the CIE-pointer field in
FDEs (since these are negative-deltas).
rdar://119351329
Added:
llvm/test/ExecutionEngine/JITLink/AArch64/MachO_subtractor_single_block.yaml
llvm/test/ExecutionEngine/JITLink/x86-64/MachO_subtractor_single_block.yaml
Modified:
llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp
llvm/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
Removed:
################################################################################
diff --git a/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp b/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp
index 409bec7a874b5f..809b2d51f05961 100644
--- a/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp
@@ -188,21 +188,41 @@ class MachOLinkGraphBuilder_arm64 : public MachOLinkGraphBuilder {
Edge::Kind DeltaKind;
Symbol *TargetSymbol;
uint64_t Addend;
+
+ bool FixingFromSymbol = true;
if (&BlockToFix == &FromSymbol->getAddressable()) {
+ if (LLVM_UNLIKELY(&BlockToFix == &ToSymbol->getAddressable())) {
+ // From and To are symbols in the same block. Decide direction by offset
+ // instead.
+ if (ToSymbol->getAddress() > FixupAddress)
+ FixingFromSymbol = true;
+ else if (FromSymbol->getAddress() > FixupAddress)
+ FixingFromSymbol = false;
+ else
+ FixingFromSymbol = FromSymbol->getAddress() >= ToSymbol->getAddress();
+ } else
+ FixingFromSymbol = true;
+ } else {
+ if (&BlockToFix == &ToSymbol->getAddressable())
+ FixingFromSymbol = false;
+ else {
+ // BlockToFix was neither FromSymbol nor ToSymbol.
+ return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
+ "either 'A' or 'B' (or a symbol in one "
+ "of their alt-entry groups)");
+ }
+ }
+
+ if (FixingFromSymbol) {
TargetSymbol = ToSymbol;
DeltaKind = (SubRI.r_length == 3) ? aarch64::Delta64 : aarch64::Delta32;
Addend = FixupValue + (FixupAddress - FromSymbol->getAddress());
// FIXME: handle extern 'from'.
- } else if (&BlockToFix == &ToSymbol->getAddressable()) {
+ } else {
TargetSymbol = &*FromSymbol;
DeltaKind =
(SubRI.r_length == 3) ? aarch64::NegDelta64 : aarch64::NegDelta32;
Addend = FixupValue - (FixupAddress - ToSymbol->getAddress());
- } else {
- // BlockToFix was neither FromSymbol nor ToSymbol.
- return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
- "either 'A' or 'B' (or a symbol in one "
- "of their alt-entry groups)");
}
return PairRelocInfo(DeltaKind, TargetSymbol, Addend);
diff --git a/llvm/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp b/llvm/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
index 49f619357f0891..eeca27771ad646 100644
--- a/llvm/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
@@ -179,21 +179,41 @@ class MachOLinkGraphBuilder_x86_64 : public MachOLinkGraphBuilder {
Edge::Kind DeltaKind;
Symbol *TargetSymbol;
uint64_t Addend;
+
+ bool FixingFromSymbol = true;
if (&BlockToFix == &FromSymbol->getAddressable()) {
+ if (LLVM_UNLIKELY(&BlockToFix == &ToSymbol->getAddressable())) {
+ // From and To are symbols in the same block. Decide direction by offset
+ // instead.
+ if (ToSymbol->getAddress() > FixupAddress)
+ FixingFromSymbol = true;
+ else if (FromSymbol->getAddress() > FixupAddress)
+ FixingFromSymbol = false;
+ else
+ FixingFromSymbol = FromSymbol->getAddress() >= ToSymbol->getAddress();
+ } else
+ FixingFromSymbol = true;
+ } else {
+ if (&BlockToFix == &ToSymbol->getAddressable())
+ FixingFromSymbol = false;
+ else {
+ // BlockToFix was neither FromSymbol nor ToSymbol.
+ return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
+ "either 'A' or 'B' (or a symbol in one "
+ "of their alt-entry groups)");
+ }
+ }
+
+ if (FixingFromSymbol) {
TargetSymbol = ToSymbol;
DeltaKind = (SubRI.r_length == 3) ? x86_64::Delta64 : x86_64::Delta32;
Addend = FixupValue + (FixupAddress - FromSymbol->getAddress());
// FIXME: handle extern 'from'.
- } else if (&BlockToFix == &ToSymbol->getAddressable()) {
+ } else {
TargetSymbol = FromSymbol;
DeltaKind =
(SubRI.r_length == 3) ? x86_64::NegDelta64 : x86_64::NegDelta32;
Addend = FixupValue - (FixupAddress - ToSymbol->getAddress());
- } else {
- // BlockToFix was neither FromSymbol nor ToSymbol.
- return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
- "either 'A' or 'B' (or a symbol in one "
- "of their alt-entry chains)");
}
return PairRelocInfo(DeltaKind, TargetSymbol, Addend);
diff --git a/llvm/test/ExecutionEngine/JITLink/AArch64/MachO_subtractor_single_block.yaml b/llvm/test/ExecutionEngine/JITLink/AArch64/MachO_subtractor_single_block.yaml
new file mode 100644
index 00000000000000..dec9f274072cb7
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/AArch64/MachO_subtractor_single_block.yaml
@@ -0,0 +1,306 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-jitlink -noexec %t
+#
+# Check that MachO::ARM64_RELOC_SUBTRACTOR relocations work when the fixup
+# location and target are in the same block (in this case in the __eh_frame
+# section).
+
+--- !mach-o
+FileHeader:
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diff --git a/llvm/test/ExecutionEngine/JITLink/x86-64/MachO_subtractor_single_block.yaml b/llvm/test/ExecutionEngine/JITLink/x86-64/MachO_subtractor_single_block.yaml
new file mode 100644
index 00000000000000..704c611cf9f797
--- /dev/null
+++ b/llvm/test/ExecutionEngine/JITLink/x86-64/MachO_subtractor_single_block.yaml
@@ -0,0 +1,159 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-jitlink -noexec %t
+#
+# Check that MachO::X86_64_RELOC_SUBTRACTOR relocations work when the fixup
+# location and target are in the same block (in this case in the __eh_frame
+# section).
+
+--- !mach-o
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