[lld] 525c7d8 - [lld-macho] Handle alignment correctly when merging InputSections

[Jez Ng via llvm-commits]

Author: Jez Ng
Date: 2020-06-17T20:41:28-07:00
New Revision: 525c7d8cda72c00c85de4989bcddefd4fb9a14a1

URL: https://github.com/llvm/llvm-project/commit/525c7d8cda72c00c85de4989bcddefd4fb9a14a1
DIFF: https://github.com/llvm/llvm-project/commit/525c7d8cda72c00c85de4989bcddefd4fb9a14a1.diff

LOG: [lld-macho] Handle alignment correctly when merging InputSections

Summary:
Previously, we weren't updating isecAddr when aligning InputSections,
resulting in truncated sections under the right conditions.

Reviewers: #lld-macho, compnerd

Reviewed By: #lld-macho, compnerd

Subscribers: smeenai, compnerd, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81298

Added: 
    

Modified: 
    lld/MachO/MergedOutputSection.cpp
    lld/test/MachO/section-merge.s

Removed: 
    


################################################################################
diff  --git a/lld/MachO/MergedOutputSection.cpp b/lld/MachO/MergedOutputSection.cpp
index 1983736d7879..2d0be2538347 100644
--- a/lld/MachO/MergedOutputSection.cpp
+++ b/lld/MachO/MergedOutputSection.cpp
@@ -32,11 +32,13 @@ void MergedOutputSection::mergeInput(InputSection *input) {
 void MergedOutputSection::finalize() {
   uint64_t isecAddr = addr;
   uint64_t isecFileOff = fileOff;
-  for (InputSection *i : inputs) {
-    i->outSecOff = alignTo(isecAddr, i->align) - addr;
-    i->outSecFileOff = alignTo(isecFileOff, i->align) - fileOff;
-    isecAddr += i->getSize();
-    isecFileOff += i->getFileSize();
+  for (InputSection *isec : inputs) {
+    isecAddr = alignTo(isecAddr, isec->align);
+    isecFileOff = alignTo(isecFileOff, isec->align);
+    isec->outSecOff = isecAddr - addr;
+    isec->outSecFileOff = isecFileOff - fileOff;
+    isecAddr += isec->getSize();
+    isecFileOff += isec->getFileSize();
   }
   size = isecAddr - addr;
   fileSize = isecFileOff - fileOff;

diff  --git a/lld/test/MachO/section-merge.s b/lld/test/MachO/section-merge.s
index 33e1eddd3044..69c55a047b49 100644
--- a/lld/test/MachO/section-merge.s
+++ b/lld/test/MachO/section-merge.s
@@ -1,31 +1,22 @@
 # REQUIRES: x86
 # RUN: mkdir -p %t
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %p/Inputs/libhello.s \
-# RUN:   -o %t/libhello.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %p/Inputs/libgoodbye.s \
-# RUN:   -o %t/libgoodbye.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %p/Inputs/libfunction.s \
-# RUN:   -o %t/libfunction.o
-# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s \
-# RUN:   -o %t/main.o
-# RUN: lld -flavor darwinnew -o %t/output %t/libfunction.o %t/libgoodbye.o %t/libhello.o %t/main.o
+## Verify that we preserve alignment when merging sections.
+# RUN: echo ".globl _foo; .data; .p2align 0; _foo: .byte 0xca" | llvm-mc -filetype=obj -triple=x86_64-apple-darwin -o %t/foo.o
+# RUN: echo ".globl _bar; .data; .p2align 2; _bar: .byte 0xfe" | llvm-mc -filetype=obj -triple=x86_64-apple-darwin -o %t/bar.o
+# RUN: echo ".globl _baz; .data; .p2align 3; _baz: .byte 0xba" | llvm-mc -filetype=obj -triple=x86_64-apple-darwin -o %t/baz.o
+# RUN: echo ".globl _qux; .data; .p2align 0; _qux: .quad 0xdeadbeef" | llvm-mc -filetype=obj -triple=x86_64-apple-darwin -o %t/qux.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/main.o
+# RUN: lld -flavor darwinnew -o %t/output %t/foo.o %t/bar.o %t/baz.o %t/qux.o %t/main.o
 
-# RUN: llvm-objdump --syms %t/output | FileCheck %s
-# CHECK:      SYMBOL TABLE:
-# CHECK-DAG:  {{[0-9a-z]+}} g     O __TEXT,__cstring _goodbye_world
-# CHECK-DAG:  {{[0-9a-z]+}} g     O __TEXT,__cstring _hello_its_me
-# CHECK-DAG:  {{[0-9a-z]+}} g     O __TEXT,__cstring _hello_world
-# CHECK-DAG:  {{[0-9a-z]+}} g     F __TEXT,__text _main
-# CHECK-DAG:  {{[0-9a-z]+}} g     F __TEXT,__text _some_function
+# RUN: llvm-objdump --syms --section=__data --full-contents %t/output | FileCheck %s
+# CHECK:     SYMBOL TABLE:
+# CHECK-DAG: [[#%x, ADDR:]]      g     O __DATA,__data _foo
+# CHECK-DAG: {{0*}}[[#ADDR+0x4]] g     O __DATA,__data _bar
+# CHECK-DAG: {{0*}}[[#ADDR+0x8]] g     O __DATA,__data _baz
+# CHECK-DAG: {{0*}}[[#ADDR+0x9]] g     O __DATA,__data _qux
 
-# RUN: llvm-objdump -d %t/output | FileCheck %s --check-prefix DATA
-# DATA:      Disassembly of section __TEXT,__text:
-# DATA:        {{0*}}[[#%x,BASE:]] <_some_function>:
-# DATA-NEXT:             [[#BASE]]: 48 c7 c0 01 00 00 00          movq    $1, %rax
-# DATA-NEXT:       [[#BASE + 0x7]]: c3                            retq
-# DATA:        {{0*}}[[#%x,MAIN:]] <_main>:
-# DATA-NEXT:             [[#MAIN]]: 48 c7 c0 00 00 00 00          movq    $0, %rax
-# DATA-NEXT:       [[#MAIN + 0x7]]: c3                            retq
+# CHECK:      Contents of section __data:
+# CHECK-NEXT: {{0*}}[[#ADDR]] ca000000 fe000000 baefbead de000000
 
 .section __TEXT,__text
 .global _main