[lld] [MTE] Allow android note for static executables. (#77078)
Florian pointed out that we're accidentally eliding the Android note for
static executables, as it's guarded behind the "can have memtag globals"
conditional. Of course, memtag globals are unsupported for static
executables, but we should still allow static binaries to produce the
Android note (as that's the only way they get MTE).
GitOrigin-RevId: a831a21e4d8d41b044edaf61a90debb2ad756bda
diff --git a/ELF/Arch/AArch64.cpp b/ELF/Arch/AArch64.cpp
index 048f0ec..54b0a84 100644
--- a/ELF/Arch/AArch64.cpp
+++ b/ELF/Arch/AArch64.cpp
@@ -1025,8 +1025,7 @@
// symbols should also be built with tagging. But, to handle these cases, we
// demote the symbol to be untagged.
void lld::elf::createTaggedSymbols(const SmallVector<ELFFileBase *, 0> &files) {
- assert(config->emachine == EM_AARCH64 &&
- config->androidMemtagMode != ELF::NT_MEMTAG_LEVEL_NONE);
+ assert(hasMemtag());
// First, collect all symbols that are marked as tagged, and count how many
// times they're marked as tagged.
diff --git a/ELF/SyntheticSections.cpp b/ELF/SyntheticSections.cpp
index 2b32eb3..19fced5 100644
--- a/ELF/SyntheticSections.cpp
+++ b/ELF/SyntheticSections.cpp
@@ -1450,7 +1450,7 @@
if (config->zPacPlt)
addInt(DT_AARCH64_PAC_PLT, 0);
- if (config->androidMemtagMode != ELF::NT_MEMTAG_LEVEL_NONE) {
+ if (hasMemtag()) {
addInt(DT_AARCH64_MEMTAG_MODE, config->androidMemtagMode == NT_MEMTAG_LEVEL_ASYNC);
addInt(DT_AARCH64_MEMTAG_HEAP, config->androidMemtagHeap);
addInt(DT_AARCH64_MEMTAG_STACK, config->androidMemtagStack);
diff --git a/ELF/Writer.cpp b/ELF/Writer.cpp
index a84e486..7b9880a 100644
--- a/ELF/Writer.cpp
+++ b/ELF/Writer.cpp
@@ -291,6 +291,11 @@
}
}
+bool elf::hasMemtag() {
+ return config->emachine == EM_AARCH64 &&
+ config->androidMemtagMode != ELF::NT_MEMTAG_LEVEL_NONE;
+}
+
// Fully static executables don't support MTE globals at this point in time, as
// we currently rely on:
// - A dynamic loader to process relocations, and
@@ -298,8 +303,7 @@
// This restriction could be removed in future by re-using some of the ideas
// that ifuncs use in fully static executables.
bool elf::canHaveMemtagGlobals() {
- return config->emachine == EM_AARCH64 &&
- config->androidMemtagMode != ELF::NT_MEMTAG_LEVEL_NONE &&
+ return hasMemtag() &&
(config->relocatable || config->shared || needsInterpSection());
}
@@ -397,11 +401,13 @@
std::make_unique<SymbolTableSection<ELFT>>(*part.dynStrTab);
part.dynamic = std::make_unique<DynamicSection<ELFT>>();
- if (canHaveMemtagGlobals()) {
+ if (hasMemtag()) {
part.memtagAndroidNote = std::make_unique<MemtagAndroidNote>();
add(*part.memtagAndroidNote);
- part.memtagDescriptors = std::make_unique<MemtagDescriptors>();
- add(*part.memtagDescriptors);
+ if (canHaveMemtagGlobals()) {
+ part.memtagDescriptors = std::make_unique<MemtagDescriptors>();
+ add(*part.memtagDescriptors);
+ }
}
if (config->androidPackDynRelocs)
diff --git a/ELF/Writer.h b/ELF/Writer.h
index eaf021a..aac8176 100644
--- a/ELF/Writer.h
+++ b/ELF/Writer.h
@@ -57,6 +57,7 @@
bool isMicroMips();
bool isMipsR6();
+bool hasMemtag();
bool canHaveMemtagGlobals();
} // namespace lld::elf
diff --git a/test/ELF/aarch64-memtag-android-abi.s b/test/ELF/aarch64-memtag-android-abi.s
index e574448..7c6a26a 100644
--- a/test/ELF/aarch64-memtag-android-abi.s
+++ b/test/ELF/aarch64-memtag-android-abi.s
@@ -56,6 +56,18 @@
# BAD-MODE: error: unknown --android-memtag-mode value: "asymm", should be one of
# BAD-MODE: {async, sync, none}
+# RUN: ld.lld -static --android-memtag-mode=sync --android-memtag-heap \
+# RUN: --android-memtag-stack %t.o -o %t
+# RUN: llvm-readelf --memtag %t | FileCheck %s --check-prefixes=STATIC
+
+# STATIC: Memtag Dynamic Entries:
+# STATIC-NEXT: < none found >
+# STATIC: Memtag Android Note:
+# STATIC-NEXT: Tagging Mode: SYNC
+# STATIC-NEXT: Heap: Enabled
+# STATIC-NEXT: Stack: Enabled
+
+
.globl _start
_start:
ret
