AsmPrinter: Emit the DwarfStringPool offset directly when possible
Change `DwarfStringPool` to calculate byte offsets on-the-fly, and
update `DwarfUnit::getLocalString()` to use a `DIEInteger` instead of a
`DIEDelta` when Dwarf doesn't use relocations (i.e., Mach-O). This
eliminates another call to `EmitLabelDifference()`, and drops memory
usage from 865 MB down to 861 MB, around 0.5%.
(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)
llvm-svn: 238114
diff --git a/llvm/test/DebugInfo/X86/stringpool.ll b/llvm/test/DebugInfo/X86/stringpool.ll
index 23c0fc4..62b2b1b 100644
--- a/llvm/test/DebugInfo/X86/stringpool.ll
+++ b/llvm/test/DebugInfo/X86/stringpool.ll
@@ -18,7 +18,7 @@
; LINUX: .section .debug_str,"MS",@progbits,1
; LINUX: yyyy
; DARWIN: .section __DWARF,__debug_str,regular,debug
-; DARWIN: yyyy
+; DARWIN: .asciz "yyyy" ## string offset=[[YYYY:[0-9]+]]
; Verify that we refer to 'yyyy' with a relocation.
; LINUX: .long .Linfo_string3 # DW_AT_name
@@ -30,9 +30,8 @@
; LINUX-NEXT: .byte 3
; LINUX-NEXT: .quad yyyy
-; Verify that we refer to 'yyyy' without a relocation.
-; DARWIN: Lset[[ID:[0-9]+]] = Linfo_string3-Linfo_string ## DW_AT_name
-; DARWIN-NEXT: .long Lset[[ID]]
+; Verify that we refer to 'yyyy' with a direct offset.
+; DARWIN: .long [[YYYY]]
; DARWIN-NEXT: .long {{[0-9]+}} ## DW_AT_type
; DARWIN-NEXT: ## DW_AT_external
; DARWIN-NEXT: .byte 1 ## DW_AT_decl_file