[LLD][COFF] Align import directory chunk. (#80014)
The loader can usually handle an unaligned import dir chunk, but It's not
optimal and it's not what MSVC link.exe does.
Windows refuses to load ARM64X binaries with unaligned import directory.
aarch64 and arm64ec imports are shared in such binaries as much as
possible. As long as they use the same set of functions from given import
directory, both the directory and import addresses chunk are just shared.
When used set of functions differs, ARM64X dynamic relocations are used
to modify import dir to point to different names and import addresses for
its EC view. I suspect that the loader expects some alignment on ARM64X
dynamic relocation offset and may not be the case when relocated import
dir is not aligned.
GitOrigin-RevId: c8c3fe70ae09a48408ee15a256e52a4624e0291c
diff --git a/COFF/DLL.cpp b/COFF/DLL.cpp
index 6b516d8..d0b74ac 100644
--- a/COFF/DLL.cpp
+++ b/COFF/DLL.cpp
@@ -110,7 +110,7 @@
// A chunk for the import descriptor table.
class ImportDirectoryChunk : public NonSectionChunk {
public:
- explicit ImportDirectoryChunk(Chunk *n) : dllName(n) {}
+ explicit ImportDirectoryChunk(Chunk *n) : dllName(n) { setAlignment(4); }
size_t getSize() const override { return sizeof(ImportDirectoryTableEntry); }
void writeTo(uint8_t *buf) const override {
diff --git a/test/COFF/imports.test b/test/COFF/imports.test
index 390626b..b646436 100644
--- a/test/COFF/imports.test
+++ b/test/COFF/imports.test
@@ -48,3 +48,8 @@
MERGE-NEXT: Symbol: (50)
MERGE-NEXT: Symbol: MessageBoxA (1)
MERGE-NEXT: }
+
+# Verify that import table is properly aligned.
+# RUN: llvm-readobj --headers %t.exe | FileCheck -check-prefix=IMPORTDIR %s
+IMPORTDIR: ImportTableRVA: 0x1068
+IMPORTDIR-NEXT: ImportTableSize: 0x28
diff --git a/test/COFF/pdb-publics-import.test b/test/COFF/pdb-publics-import.test
index 83f087b..3f3ab36 100644
--- a/test/COFF/pdb-publics-import.test
+++ b/test/COFF/pdb-publics-import.test
@@ -115,7 +115,7 @@
CHECK-NEXT: initialized data
CHECK-NEXT: read permissions
CHECK-NEXT: {{[0-9]+}} | S_COFFGROUP [size = 28] `.idata$2`
-CHECK-NEXT: length = 40, addr = 0002:0061
+CHECK-NEXT: length = 40, addr = 0002:0064
CHECK-NEXT: characteristics =
CHECK-NEXT: initialized data
CHECK-NEXT: read permissions
@@ -162,9 +162,9 @@
CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
CHECK-NEXT: SC[.rdata] | mod = 3, 0002:0028, size = 33, data crc = 0, reloc crc = 0
CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
-CHECK-NEXT: SC[.rdata] | mod = 3, 0002:0061, size = 20, data crc = 0, reloc crc = 0
+CHECK-NEXT: SC[.rdata] | mod = 3, 0002:0064, size = 20, data crc = 0, reloc crc = 0
CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
-CHECK-NEXT: SC[.rdata] | mod = 3, 0002:0081, size = 20, data crc = 0, reloc crc = 0
+CHECK-NEXT: SC[.rdata] | mod = 3, 0002:0084, size = 20, data crc = 0, reloc crc = 0
CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
CHECK-NEXT: SC[.rdata] | mod = 3, 0002:0104, size = 8, data crc = 0, reloc crc = 0
CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ
