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[lld] Mark target section as code section when merging code sections into a data section. #72030

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Merged
merged 1 commit into from
Nov 14, 2023
Merged

[lld] Mark target section as code section when merging code sections into a data section. #72030

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8 changes: 8 additions & 0 deletions lld/COFF/Writer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -347,6 +347,14 @@ void OutputSection::merge(OutputSection *other) {
contribSections.insert(contribSections.end(), other->contribSections.begin(),
other->contribSections.end());
other->contribSections.clear();

// MS link.exe compatibility: when merging a code section into a data section,
// mark the target section as a code section.
if (other->header.Characteristics & IMAGE_SCN_CNT_CODE) {
header.Characteristics |= IMAGE_SCN_CNT_CODE;
header.Characteristics &=
~(IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_CNT_UNINITIALIZED_DATA);
}
}

// Write the section header to a given buffer.
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51 changes: 46 additions & 5 deletions lld/test/COFF/code-merge.s
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Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,8 @@
# CHECK-NEXT: PointerToLineNumbers: 0x0
# CHECK-NEXT: RelocationCount: 0
# CHECK-NEXT: LineNumberCount: 0
# CHECK-NEXT: Characteristics [ (0xC0000080)
# CHECK-NEXT: IMAGE_SCN_CNT_UNINITIALIZED_DATA (0x80)
# CHECK-NEXT: Characteristics [ (0xC0000020)
# CHECK-NEXT: IMAGE_SCN_CNT_CODE (0x20)
# CHECK-NEXT: IMAGE_SCN_MEM_READ (0x40000000)
# CHECK-NEXT: IMAGE_SCN_MEM_WRITE (0x80000000)
# CHECK-NEXT: ]
Expand All @@ -35,8 +35,8 @@
# CHECK-NEXT: PointerToLineNumbers: 0x0
# CHECK-NEXT: RelocationCount: 0
# CHECK-NEXT: LineNumberCount: 0
# CHECK-NEXT: Characteristics [ (0x40000040)
# CHECK-NEXT: IMAGE_SCN_CNT_INITIALIZED_DATA (0x40)
# CHECK-NEXT: Characteristics [ (0x40000020)
# CHECK-NEXT: IMAGE_SCN_CNT_CODE (0x20)
# CHECK-NEXT: IMAGE_SCN_MEM_READ (0x40000000)
# CHECK-NEXT: ]
# CHECK-NEXT: }
Expand Down Expand Up @@ -77,7 +77,48 @@
# CHECK-NEXT: ]

# RUN: llvm-objdump -d %t.dll | FileCheck -check-prefix=DISASM %s
# DISASM: Disassembly of section .testx3:
# DISASM: Disassembly of section .testbss:
# DISASM-EMPTY:
# DISASM-NEXT: 0000000180001000 <.testbss>:
# DISASM-NEXT: 180001000: 00 00 addb %al, (%rax)
# DISASM-NEXT: 180001002: 00 00 addb %al, (%rax)
# DISASM-NEXT: 180001004: cc int3
# DISASM-NEXT: 180001005: cc int3
# DISASM-NEXT: 180001006: cc int3
# DISASM-NEXT: 180001007: cc int3
# DISASM-NEXT: 180001008: cc int3
# DISASM-NEXT: 180001009: cc int3
# DISASM-NEXT: 18000100a: cc int3
# DISASM-NEXT: 18000100b: cc int3
# DISASM-NEXT: 18000100c: cc int3
# DISASM-NEXT: 18000100d: cc int3
# DISASM-NEXT: 18000100e: cc int3
# DISASM-NEXT: 18000100f: cc int3
# DISASM-NEXT: 180001010: 48 c7 c0 02 00 00 00 movq $0x2, %rax
# DISASM-NEXT: 180001017: c3 retq
# DISASM-EMPTY:
# DISASM-NEXT: Disassembly of section .testd:
# DISASM-EMPTY:
# DISASM-NEXT: 0000000180002000 <.testd>:
# DISASM-NEXT: 180002000: 01 00 addl %eax, (%rax)
# DISASM-NEXT: 180002002: cc int3
# DISASM-NEXT: 180002003: cc int3
# DISASM-NEXT: 180002004: cc int3
# DISASM-NEXT: 180002005: cc int3
# DISASM-NEXT: 180002006: cc int3
# DISASM-NEXT: 180002007: cc int3
# DISASM-NEXT: 180002008: cc int3
# DISASM-NEXT: 180002009: cc int3
# DISASM-NEXT: 18000200a: cc int3
# DISASM-NEXT: 18000200b: cc int3
# DISASM-NEXT: 18000200c: cc int3
# DISASM-NEXT: 18000200d: cc int3
# DISASM-NEXT: 18000200e: cc int3
# DISASM-NEXT: 18000200f: cc int3
# DISASM-NEXT: 180002010: 48 c7 c0 01 00 00 00 movq $0x1, %rax
# DISASM-NEXT: 180002017: c3 retq
# DISASM-EMPTY:
# DISASM-NEXT: Disassembly of section .testx3:
# DISASM-EMPTY:
# DISASM-NEXT: 0000000180003000 <.testx3>:
# DISASM-NEXT: 180003000: 48 c7 c0 03 00 00 00 movq $0x3, %rax
Expand Down