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[lld][linkerscript] Fix handling of DEFINED. 

Current implementation did not check that symbols is actually defined. Only checked for presence.  GNU ld documentation says,

"Return 1 if symbol is in the linker global symbol table and is defined before the statement using DEFINED in the script, otherwise return 0."

https://sourceware.org/binutils/docs/ld/Builtin-Functions.html#Builtin-Functions

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D83758
This commit is contained in:
Hafiz Abid Qadeer 2020-07-16 21:40:31 +01:00
parent 1e027b77f0
commit 1f166edeb4
3 changed files with 12 additions and 2 deletions
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5
lld/ELF/ScriptParser.cpp
View File

@ -1311,7 +1311,10 @@ Expr ScriptParser::readPrimary() {
}
if (tok == "DEFINED") {
StringRef name = readParenLiteral();
return [=] { return symtab->find(name) ? 1 : 0; };
return [=] {
Symbol *b = symtab->find(name);
return (b && b->isDefined()) ? 1 : 0;
};
}
if (tok == "LENGTH") {
StringRef name = readParenLiteral();

3
lld/test/ELF/linkerscript/Inputs/define.s
View File

@ -6,3 +6,6 @@ defined = 0
.section .bar,"a"
.quad 1
.section .test,"a"
.quad 1

6
lld/test/ELF/linkerscript/define.test
View File

@ -3,13 +3,17 @@
# RUN: ld.lld -o %t --script %s %t.o
# RUN: llvm-objdump --section-headers %t | FileCheck %s
EXTERN(extern_defined)
SECTIONS {
. = DEFINED(defined) ? 0x11000 : .;
.foo : { *(.foo*) }
. = DEFINED(notdefined) ? 0x12000 : 0x13000;
.bar : { *(.bar*) }
. = DEFINED(extern_defined) ? 0x14000 : 0x15000;
.test : { *(.test*) }
}
# CHECK: 1 .foo 00000008 0000000000011000 DATA
# CHECK: 2 .bar 00000008 0000000000013000 DATA
# CHECK: 3 .text 00000000 0000000000013008 TEXT
# CHECK: 3 .test 00000008 0000000000015000 DATA
# CHECK: 4 .text 00000000 0000000000015008 TEXT