Merging r311734:
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r311734 | ruiu | 2017-08-24 16:51:40 -0700 (Thu, 24 Aug 2017) | 44 lines
[MACH-O] Fix the ASM code generated for __stub_helpers section
Patch by Patricio Villalobos.
I discovered that lld for darwin is generating the wrong code for lazy
bindings in the __stub_helper section (at least for osx 10.12). This is
the way i can reproduce this problem, using this program:
#include <stdio.h>
int main(int argc, char **argv) {
printf("C: printf!\n");
puts("C: puts!\n");
return 0;
}
Then I link it using i have tested it in 3.9, 4.0 and 4.1 versions:
$ clang -c hello.c
$ lld -flavor darwin hello.o -o h1 -lc
When i execute the binary h1 the system gives me the following error:
C: printf!
dyld: lazy symbol binding failed:
BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB
has segment 4 which is too large (0..3)
dyld: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too
large (0..3)
Trace/BPT trap: 5
Investigating the code, it seems that the problem is that the asm code
generated in the file StubPass.cpp, specifically in the line 323,when it
adds, what it seems an arbitrary number (12) to the offset into the lazy
bind opcodes section, but it should be calculated depending on the
MachONormalizedFileBinaryWrite::lazyBindingInfo result.
I confirmed this bug by patching the code manually in the binary and
writing the right offset in the asm code (__stub_helper).
This patch fixes the content of the atom that contains the assembly code
when the offset is known.
Differential Revision: https://reviews.llvm.org/D35387
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git-svn-id: https://llvm.org/svn/llvm-project/lld/branches/release_50@319825 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ReaderWriter/MachO/ArchHandler.h b/lib/ReaderWriter/MachO/ArchHandler.h
index 70a63bd..6028006 100644
--- a/lib/ReaderWriter/MachO/ArchHandler.h
+++ b/lib/ReaderWriter/MachO/ArchHandler.h
@@ -112,6 +112,10 @@
/// info in final executables.
virtual bool isLazyPointer(const Reference &);
+ /// Reference from an __stub_helper entry to the required offset of the
+ /// lazy bind commands.
+ virtual Reference::KindValue lazyImmediateLocationKind() = 0;
+
/// Returns true if the specified relocation is paired to the next relocation.
virtual bool isPairedReloc(const normalized::Relocation &) = 0;
diff --git a/lib/ReaderWriter/MachO/ArchHandler_arm.cpp b/lib/ReaderWriter/MachO/ArchHandler_arm.cpp
index 7d15448..2f663c6 100644
--- a/lib/ReaderWriter/MachO/ArchHandler_arm.cpp
+++ b/lib/ReaderWriter/MachO/ArchHandler_arm.cpp
@@ -67,6 +67,10 @@
return invalid;
}
+ Reference::KindValue lazyImmediateLocationKind() override {
+ return lazyImmediateLocation;
+ }
+
Reference::KindValue pointerKind() override {
return invalid;
}
diff --git a/lib/ReaderWriter/MachO/ArchHandler_arm64.cpp b/lib/ReaderWriter/MachO/ArchHandler_arm64.cpp
index 10360b5..b9c815c 100644
--- a/lib/ReaderWriter/MachO/ArchHandler_arm64.cpp
+++ b/lib/ReaderWriter/MachO/ArchHandler_arm64.cpp
@@ -127,6 +127,10 @@
return pointer64;
}
+ Reference::KindValue lazyImmediateLocationKind() override {
+ return lazyImmediateLocation;
+ }
+
uint32_t dwarfCompactUnwindType() override {
return 0x03000000;
}
diff --git a/lib/ReaderWriter/MachO/ArchHandler_x86.cpp b/lib/ReaderWriter/MachO/ArchHandler_x86.cpp
index 2272bff..a2c6809 100644
--- a/lib/ReaderWriter/MachO/ArchHandler_x86.cpp
+++ b/lib/ReaderWriter/MachO/ArchHandler_x86.cpp
@@ -70,6 +70,10 @@
return delta32;
}
+ Reference::KindValue lazyImmediateLocationKind() override {
+ return lazyImmediateLocation;
+ }
+
Reference::KindValue unwindRefToEhFrameKind() override {
return invalid;
}
diff --git a/lib/ReaderWriter/MachO/ArchHandler_x86_64.cpp b/lib/ReaderWriter/MachO/ArchHandler_x86_64.cpp
index d687ca5..aee9959 100644
--- a/lib/ReaderWriter/MachO/ArchHandler_x86_64.cpp
+++ b/lib/ReaderWriter/MachO/ArchHandler_x86_64.cpp
@@ -116,6 +116,10 @@
return unwindFDEToFunction;
}
+ Reference::KindValue lazyImmediateLocationKind() override {
+ return lazyImmediateLocation;
+ }
+
Reference::KindValue unwindRefToEhFrameKind() override {
return unwindInfoToEhFrame;
}
diff --git a/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp b/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
index e58e3d2..f2e5ed7 100644
--- a/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
+++ b/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
@@ -172,6 +172,8 @@
SymbolScope &symbolScope);
void appendSection(SectionInfo *si, NormalizedFile &file);
uint32_t sectionIndexForAtom(const Atom *atom);
+ void fixLazyReferenceImm(const DefinedAtom *atom, uint32_t offset,
+ NormalizedFile &file);
typedef llvm::DenseMap<const Atom*, uint32_t> AtomToIndex;
struct AtomAndIndex { const Atom *atom; uint32_t index; SymbolScope scope; };
@@ -1423,6 +1425,8 @@
uint8_t segmentIndex;
uint64_t segmentStartAddr;
+ uint32_t offsetInBindInfo = 0;
+
for (SectionInfo *sect : _sectionInfos) {
segIndexForSection(sect, segmentIndex, segmentStartAddr);
for (const AtomInfo &info : sect->atomsAndOffsets) {
@@ -1467,6 +1471,59 @@
bind.symbolName = targ->name();
bind.addend = ref->addend();
nFile.lazyBindingInfo.push_back(bind);
+
+ // Now that we know the segmentOffset and the ordinal attribute,
+ // we can fix the helper's code
+
+ fixLazyReferenceImm(atom, offsetInBindInfo, nFile);
+
+ // 5 bytes for opcodes + variable sizes (target name + \0 and offset
+ // encode's size)
+ offsetInBindInfo +=
+ 6 + targ->name().size() + llvm::getULEB128Size(bind.segOffset);
+ if (bind.ordinal > BIND_IMMEDIATE_MASK)
+ offsetInBindInfo += llvm::getULEB128Size(bind.ordinal);
+ }
+ }
+ }
+ }
+}
+
+void Util::fixLazyReferenceImm(const DefinedAtom *atom, uint32_t offset,
+ NormalizedFile &file) {
+ for (const auto &ref : *atom) {
+ const DefinedAtom *da = dyn_cast<DefinedAtom>(ref->target());
+ if (da == nullptr)
+ return;
+
+ const Reference *helperRef = nullptr;
+ for (const Reference *hr : *da) {
+ if (hr->kindValue() == _archHandler.lazyImmediateLocationKind()) {
+ helperRef = hr;
+ break;
+ }
+ }
+ if (helperRef == nullptr)
+ continue;
+
+ // TODO: maybe get the fixed atom content from _archHandler ?
+ for (SectionInfo *sectInfo : _sectionInfos) {
+ for (const AtomInfo &atomInfo : sectInfo->atomsAndOffsets) {
+ if (atomInfo.atom == helperRef->target()) {
+ auto sectionContent =
+ file.sections[sectInfo->normalizedSectionIndex].content;
+ uint8_t *rawb =
+ file.ownedAllocations.Allocate<uint8_t>(sectionContent.size());
+ llvm::MutableArrayRef<uint8_t> newContent{rawb,
+ sectionContent.size()};
+ std::copy(sectionContent.begin(), sectionContent.end(),
+ newContent.begin());
+ llvm::support::ulittle32_t *loc =
+ reinterpret_cast<llvm::support::ulittle32_t *>(
+ &newContent[atomInfo.offsetInSection +
+ helperRef->offsetInAtom()]);
+ *loc = offset;
+ file.sections[sectInfo->normalizedSectionIndex].content = newContent;
}
}
}
diff --git a/test/mach-o/lazy-bind-x86_64.yaml b/test/mach-o/lazy-bind-x86_64.yaml
index 5c588c5..1322719 100644
--- a/test/mach-o/lazy-bind-x86_64.yaml
+++ b/test/mach-o/lazy-bind-x86_64.yaml
@@ -80,8 +80,8 @@
# CHECK-HELPERS:Disassembly of section __TEXT,__stub_helper:
# CHECK-HELPERS: 68 00 00 00 00 pushq $0
-# CHECK-HELPERS: 68 10 00 00 00 pushq $16
-# CHECK-HELPERS: 68 20 00 00 00 pushq $32
+# CHECK-HELPERS: 68 0b 00 00 00 pushq $11
+# CHECK-HELPERS: 68 16 00 00 00 pushq $22
# Make sure the stub helper is correctly aligned
# CHECK-DYLIBS: sectname __stub_helper
