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[LLD][ELF] Support OVERLAY symbol assignments #159895

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[LLD][ELF] Support OVERLAY symbol assignments #159895

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9 changes: 7 additions & 2 deletions lld/ELF/ScriptParser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -996,8 +996,13 @@ OutputDesc *ScriptParser::readOverlaySectionDescription() {
ctx.script->createOutputSection(readName(), getCurrentLocation());
osd->osec.inOverlay = true;
expect("{");
while (auto tok = till("}"))
osd->osec.commands.push_back(readInputSectionDescription(tok));
while (auto tok = till("}")) {
if (SymbolAssignment *assign = readAssignment(tok)) {
osd->osec.commands.push_back(assign);
} else {
osd->osec.commands.push_back(readInputSectionDescription(tok));
}
}
osd->osec.phdrs = readOutputSectionPhdrs();
return osd;
}
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32 changes: 32 additions & 0 deletions lld/test/ELF/linkerscript/overlay-symbol-assign.test
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@@ -0,0 +1,32 @@
# REQUIRES: x86
# RUN: echo 'nop; .section .small, "a"; .long 0; .section .big1, "a"; .quad 1; .section .big2, "a"; .quad 2;' \
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Use RUN: rm -rf %t && split-file %s %t && cd %t pattern to prepare the input assembly file.
You can use #--- a.s for assembly and #--- 1.lds for the linker script.

# RUN: | llvm-mc -filetype=obj -triple=x86_64 - -o %t.o
# RUN: ld.lld %t.o --script %s -o %t

SECTIONS {
OVERLAY 0x1000 : AT ( 0x4000 ) {
.out.big {
*(.big1)
. = ALIGN(0x100);
*(.big2)
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also define a symbol sym = .? Does GNU ld accept it?

}
.out.small { *(.small) }
}
}

## A variant of overlay.test with explicit program header assingment.
## Check that we generate two program headers consistent with the overlay

# RUN: llvm-readelf -S -l %t | FileCheck %s

# CHECK: Section Headers:
# CHECK: Name Type Address Off Size
# CHECK: .out.big PROGBITS 0000000000001000 001000 000108
# CHECK-NEXT: .out.small PROGBITS 0000000000001000 002000 000004

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just one blank line


# CHECK: Program Headers:
# CHECK: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
# CHECK-NEXT: LOAD 0x001000 0x0000000000001000 0x0000000000004000 0x000108 0x000108 R 0x1000
# CHECK-NEXT: LOAD 0x002000 0x0000000000001000 0x0000000000004108 0x000004 0x000004 R 0x1000

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delete blank lines at the end