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[LLD] [COFF] Set the right alignment for DelayDirectoryChunk (#84697)
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This makes a difference when linking executables with delay loaded
libraries for arm32; the delay loader implementation can load data from
the registry with instructions that assume alignment.

This issue does not show up when linking in MinGW mode, because a
PseudoRelocTableChunk gets injected, which also sets alignment, even if
the chunk itself is empty.

(cherry picked from commit c93c76b)
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mstorsjo authored and tstellar committed Mar 13, 2024
1 parent fcc33dc commit 2fc8bea
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Showing 2 changed files with 20 additions and 7 deletions.
2 changes: 1 addition & 1 deletion lld/COFF/DLL.cpp
Expand Up @@ -172,7 +172,7 @@ binImports(COFFLinkerContext &ctx,
// A chunk for the delay import descriptor table etnry.
class DelayDirectoryChunk : public NonSectionChunk {
public:
explicit DelayDirectoryChunk(Chunk *n) : dllName(n) {}
explicit DelayDirectoryChunk(Chunk *n) : dllName(n) { setAlignment(4); }

size_t getSize() const override {
return sizeof(delay_import_directory_table_entry);
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25 changes: 19 additions & 6 deletions lld/test/COFF/delayimports-armnt.yaml
Expand Up @@ -6,16 +6,17 @@
# RUN: llvm-readobj --coff-imports %t.exe | FileCheck -check-prefix=IMPORT %s
# RUN: llvm-readobj --coff-basereloc %t.exe | FileCheck -check-prefix=BASEREL %s
# RUN: llvm-objdump --no-print-imm-hex -d %t.exe | FileCheck --check-prefix=DISASM %s
# RUN: llvm-readobj --file-headers %t.exe | FileCheck -check-prefix=DIR %s

# IMPORT: Format: COFF-ARM
# IMPORT-NEXT: Arch: thumb
# IMPORT-NEXT: AddressSize: 32bit
# IMPORT-NEXT: DelayImport {
# IMPORT-NEXT: Name: library.dll
# IMPORT-NEXT: Attributes: 0x1
# IMPORT-NEXT: ModuleHandle: 0x3000
# IMPORT-NEXT: ImportAddressTable: 0x3008
# IMPORT-NEXT: ImportNameTable: 0x2040
# IMPORT-NEXT: ModuleHandle: 0x3008
# IMPORT-NEXT: ImportAddressTable: 0x3010
# IMPORT-NEXT: ImportNameTable: 0x2044
# IMPORT-NEXT: BoundDelayImportTable: 0x0
# IMPORT-NEXT: UnloadDelayImportTable: 0x0
# IMPORT-NEXT: Import {
Expand Down Expand Up @@ -43,7 +44,7 @@
# BASEREL-NEXT: }
# BASEREL-NEXT: Entry {
# BASEREL-NEXT: Type: HIGHLOW
# BASEREL-NEXT: Address: 0x3008
# BASEREL-NEXT: Address: 0x3010
# BASEREL-NEXT: }
# BASEREL-NEXT: Entry {
# BASEREL-NEXT: Type: ABSOLUTE
Expand All @@ -52,20 +53,24 @@
# BASEREL-NEXT: ]
#
# DISASM: 00401000 <.text>:
# DISASM: 40100c: f243 0c08 movw r12, #12296
# DISASM: 40100c: f243 0c10 movw r12, #12304
# DISASM-NEXT: f2c0 0c40 movt r12, #64
# DISASM-NEXT: f000 b800 b.w {{.+}} @ imm = #0
# DISASM-NEXT: e92d 480f push.w {r0, r1, r2, r3, r11, lr}
# DISASM-NEXT: f20d 0b10 addw r11, sp, #16
# DISASM-NEXT: ed2d 0b10 vpush {d0, d1, d2, d3, d4, d5, d6, d7}
# DISASM-NEXT: 4661 mov r1, r12
# DISASM-NEXT: f242 0000 movw r0, #8192
# DISASM-NEXT: f242 0004 movw r0, #8196
# DISASM-NEXT: f2c0 0040 movt r0, #64
# DISASM-NEXT: f7ff ffe7 bl 0x401000 <.text>
# DISASM-NEXT: 4684 mov r12, r0
# DISASM-NEXT: ecbd 0b10 vpop {d0, d1, d2, d3, d4, d5, d6, d7}
# DISASM-NEXT: e8bd 480f pop.w {r0, r1, r2, r3, r11, lr}
# DISASM-NEXT: 4760 bx r12
#
# DIR: DelayImportDescriptorRVA: 0x2004
# DIR-NEXT: DelayImportDescriptorSize: 0x40


--- !COFF
header:
Expand All @@ -80,6 +85,14 @@ sections:
- VirtualAddress: 0
SymbolName: __imp_function
Type: IMAGE_REL_ARM_MOV32T
- Name: .rdata
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 01
- Name: .data
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
Alignment: 1
SectionData: 02
symbols:
- Name: .text
Value: 0
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