From eb4b5a36a6331a0de3559a01e6854895cacce6b3 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Tue, 10 Mar 2020 15:41:57 -0700 Subject: [PATCH] [ELF] Move --print-map(-M)/--cref before checkSections() and openFile() -M output can be useful when diagnosing an "error: output file too large" problem (emitted in openFile()). I just ran into such a situation where I had to debug an erronerous Linux kernel linker script. It tried to create a file larger than INT64_MAX bytes. This patch could have helped https://bugs.llvm.org/show_bug.cgi?id=44715 as well. Reviewed By: grimar Differential Revision: https://reviews.llvm.org/D75966 --- lld/ELF/Writer.cpp | 12 +++++------ lld/test/ELF/linkerscript/output-too-large.s | 31 ++++++++++++++++++++++------ 2 files changed, 31 insertions(+), 12 deletions(-) diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp index d6678ac..c916f35 100644 --- a/lld/ELF/Writer.cpp +++ b/lld/ELF/Writer.cpp @@ -595,6 +595,12 @@ template void Writer::run() { for (OutputSection *sec : outputSections) sec->addr = 0; + // Handle --print-map(-M)/--Map and --cref. Dump them before checkSections() + // because the files may be useful in case checkSections() or openFile() + // fails, for example, due to an erroneous file size. + writeMapFile(); + writeCrossReferenceTable(); + if (config->checkSections) checkSections(); @@ -621,12 +627,6 @@ template void Writer::run() { if (errorCount()) return; - // Handle -Map and -cref options. - writeMapFile(); - writeCrossReferenceTable(); - if (errorCount()) - return; - if (auto e = buffer->commit()) error("failed to write to the output file: " + toString(std::move(e))); } diff --git a/lld/test/ELF/linkerscript/output-too-large.s b/lld/test/ELF/linkerscript/output-too-large.s index a5130d2..d916a2e 100644 --- a/lld/test/ELF/linkerscript/output-too-large.s +++ b/lld/test/ELF/linkerscript/output-too-large.s @@ -1,12 +1,31 @@ # REQUIRES: x86 -# RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %s -o %t.o -# RUN: echo "SECTIONS { .text : { . = 0xffffffff; *(.text*); } }" > %t.script -# RUN: not ld.lld --no-check-sections --script %t.script %t.o -o /dev/null 2>&1 | FileCheck %s +# RUN: llvm-mc -filetype=obj -triple=i686 %s -o %t1.o +# RUN: echo "SECTIONS { .text : { . = 0xffffffff; *(.text*); } }" > %t1.script +# RUN: not ld.lld --no-check-sections -T %t1.script %t1.o -o /dev/null 2>&1 | FileCheck %s -# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o -# RUN: echo "SECTIONS { .text : { . = 0x8fffffffffffffff; *(.text*); } }" > %t.script -# RUN: not ld.lld --no-check-sections --script %t.script %t.o -o /dev/null 2>&1 | FileCheck %s +## Error if an address is greater than or equal to 2**32 for ELF32. +## When -M is specified, print the link map even if such an error occurs, +## because the link map can help diagnose problems. +# RUN: not ld.lld -T %t1.script %t1.o -M -o /dev/null 2>&1 | \ +# RUN: FileCheck --check-prefix=MAP1 %s + +# MAP1: VMA LMA Size Align Out In Symbol +# MAP1-NEXT: 0 0 100000001 4 .text +# MAP1-NEXT: 0 0 ffffffff 1 . = 0xffffffff +# MAP1-NEXT: 100000000 100000000 1 4 {{.*}}.o:(.text) +# MAP1: error: section .text at 0x0 of size 0x100000001 exceeds available address space + +## Error if an address is greater than or equal to 2**63. +## Print a link map if -M is specified. +# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t2.o +# RUN: echo "SECTIONS { .text : { . = 0x8fffffffffffffff; *(.text*); } }" > %t2.script +# RUN: not ld.lld -T %t2.script -M %t2.o -o /dev/null 2>&1 | \ +# RUN: FileCheck --check-prefixes=MAP2,CHECK %s + +# MAP2: VMA LMA Size Align Out In Symbol +# MAP2: 9000000000000000 9000000000000000 1 4 {{.*}}.o:(.text) +# MAP2-NEXT: 9000000000000000 9000000000000000 0 1 _start # CHECK: error: output file too large -- 2.7.4