[lld] r294374 - [ELF] Handle output section alignment in linker scripts

[Petr Hosek via llvm-commits]

Author: phosek
Date: Tue Feb  7 17:42:31 2017
New Revision: 294374

URL: http://llvm.org/viewvc/llvm-project?rev=294374&view=rev
Log:
[ELF] Handle output section alignment in linker scripts

LLD already parses ALIGN expression to specifiy alignment for output
sections in linker scripts but it never applies the alignment to the
output section. This change handles that.

Differential Revision: https://reviews.llvm.org/D29689

Added:
    lld/trunk/test/ELF/linkerscript/section-align.s
Modified:
    lld/trunk/ELF/LinkerScript.cpp

Modified: lld/trunk/ELF/LinkerScript.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.cpp?rev=294374&r1=294373&r2=294374&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.cpp (original)
+++ lld/trunk/ELF/LinkerScript.cpp Tue Feb  7 17:42:31 2017
@@ -557,6 +557,10 @@ void LinkerScript<ELFT>::assignOffsets(O
   if (!Sec)
     return;
 
+  // Handle align (e.g. ".foo : ALIGN(16) { ... }").
+  if (Cmd->AlignExpr)
+    Sec->updateAlignment(Cmd->AlignExpr(0));
+
   // Try and find an appropriate memory region to assign offsets in.
   CurMemRegion = findMemoryRegion(Cmd, Sec);
   if (CurMemRegion)

Added: lld/trunk/test/ELF/linkerscript/section-align.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/linkerscript/section-align.s?rev=294374&view=auto
==============================================================================
--- lld/trunk/test/ELF/linkerscript/section-align.s (added)
+++ lld/trunk/test/ELF/linkerscript/section-align.s Tue Feb  7 17:42:31 2017
@@ -0,0 +1,62 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+
+# RUN: echo "SECTIONS { \
+# RUN:   .aaa : ALIGN(4096) { *(.aaa) } \
+# RUN:   .bbb : ALIGN(4096 * 4) { *(.bbb) } \
+# RUN:   .ccc : ALIGN(4096 * 8) { *(.ccc) } \
+# RUN: }" > %t.script
+# RUN: ld.lld -o %t1 --script %t.script %t
+# RUN: llvm-readobj -sections %t1 | FileCheck %s
+
+.global _start
+_start:
+ nop
+
+// CHECK:      Name: .aaa
+// CHECK-NEXT: Type: SHT_PROGBITS
+// CHECK-NEXT: Flags [
+// CHECK-NEXT:   SHF_ALLOC
+// CHECK-NEXT: ]
+// CHECK-NEXT: Address:
+// CHECK-NEXT: Offset:
+// CHECK-NEXT: Size: 8
+// CHECK-NEXT: Link: 0
+// CHECK-NEXT: Info: 0
+// CHECK-NEXT: AddressAlignment: 4096
+// CHECK-NEXT: EntrySize:
+
+.section .aaa, "a"
+.quad 0
+
+// CHECK:      Name: .bbb
+// CHECK-NEXT: Type: SHT_PROGBITS
+// CHECK-NEXT: Flags [
+// CHECK-NEXT:   SHF_ALLOC
+// CHECK-NEXT: ]
+// CHECK-NEXT: Address:
+// CHECK-NEXT: Offset:
+// CHECK-NEXT: Size: 8
+// CHECK-NEXT: Link: 0
+// CHECK-NEXT: Info: 0
+// CHECK-NEXT: AddressAlignment: 16384
+// CHECK-NEXT: EntrySize:
+
+.section .bbb, "a"
+.quad 0
+
+// CHECK:      Name: .ccc
+// CHECK-NEXT: Type: SHT_PROGBITS
+// CHECK-NEXT: Flags [
+// CHECK-NEXT:   SHF_ALLOC
+// CHECK-NEXT: ]
+// CHECK-NEXT: Address:
+// CHECK-NEXT: Offset:
+// CHECK-NEXT: Size: 8
+// CHECK-NEXT: Link: 0
+// CHECK-NEXT: Info: 0
+// CHECK-NEXT: AddressAlignment: 32768
+// CHECK-NEXT: EntrySize:
+
+.section .ccc, "a"
+.quad 0