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[LLD] - Improve handling of AT> linker script commands 

Patch by Konstantin Schwarz!

The condition to create a new phdr must also check the usage of "AT>" 
linker script command, and create a new PT_LOAD header if a new LMARegion is used.

This fixes PR38307

Differential revision: https://reviews.llvm.org/D50052

llvm-svn: 338679
This commit is contained in:
George Rimar 2018-08-02 08:07:07 +00:00
parent 268adb2265
commit 34bdf27eaa
3 changed files with 48 additions and 5 deletions
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12
lld/ELF/Writer.cpp
View File

@ -1815,12 +1815,14 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
// Segments are contiguous memory regions that has the same attributes
// (e.g. executable or writable). There is one phdr for each segment.
// Therefore, we need to create a new phdr when the next section has
// different flags or is loaded at a discontiguous address using AT linker
// script command. At the same time, we don't want to create a separate
// load segment for the headers, even if the first output section has
// an AT attribute.
// different flags or is loaded at a discontiguous address or memory
// region using AT or AT> linker script command, respectively. At the same
// time, we don't want to create a separate load segment for the headers,
// even if the first output section has an AT or AT> attribute.
uint64_t NewFlags = computeFlags(Sec->getPhdrFlags());
if ((Sec->LMAExpr && Load->LastSec != Out::ProgramHeaders) ||
if (((Sec->LMAExpr ||
(Sec->LMARegion && (Sec->LMARegion != Load->FirstSec->LMARegion))) &&
Load->LastSec != Out::ProgramHeaders) ||
Sec->MemRegion != Load->FirstSec->MemRegion || Flags != NewFlags) {
Load = AddHdr(PT_LOAD, NewFlags);

11
lld/test/ELF/linkerscript/Inputs/at6.s Normal file
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@ -0,0 +1,11 @@
.global _start
.text
_start:
nop
.section .sec1,"aw",@progbits
.long 1
.section .sec2,"aw",@progbits
.long 2

30
lld/test/ELF/linkerscript/at6.test Normal file
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@ -0,0 +1,30 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/at6.s -o %t.o
# RUN: ld.lld %t.o --script %s -o %t
# RUN: llvm-readelf -sections -program-headers %t | FileCheck %s
MEMORY {
FLASH : ORIGIN = 0x08000000, LENGTH = 0x100
RAM : ORIGIN = 0x20000000, LENGTH = 0x200
}
SECTIONS {
.text : { *(.text) } > FLASH
.sec1 : { *(.sec1) } > RAM
.sec2 : { *(.sec2) } > RAM AT > FLASH
}
# Make sure we create a separate PT_LOAD entry for .sec2. Previously,
# it was added to the PT_LOAD entry of .sec1
# CHECK: Name Type Address Off
# CHECK: .text PROGBITS 0000000008000000 001000
# CHECK: .sec1 PROGBITS 0000000020000000 002000
# CHECK: .sec2 PROGBITS 0000000020000004 002004
# CHECK: Program Headers:
# CHECK: Type Offset VirtAddr PhysAddr
# CHECK-NEXT: LOAD 0x001000 0x0000000008000000 0x0000000008000000
# CHECK-NEXT: LOAD 0x002000 0x0000000020000000 0x0000000020000000
# CHECK-NEXT: LOAD 0x002004 0x0000000020000004 0x0000000008000001
# CHECK-NOT: LOAD