Bruno Cardoso Lopes d2335534c5 [AsmPrinter] Access pointers to globals via pcrel GOT entries ... Front-ends could use global unnamed_addr to hold pointers to other symbols, like @gotequivalent below: @foo = global i32 42 @gotequivalent = private unnamed_addr constant i32* @foo @delta = global i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequivalent to i64), i64 ptrtoint (i32* @delta to i64)) to i32) The global @delta holds a data "PC"-relative offset to @gotequivalent, an unnamed pointer to @foo. The darwin/x86-64 assembly output for this follows: .globl _foo _foo: .long 42 .globl _gotequivalent _gotequivalent: .quad _foo .globl _delta _delta: .long _gotequivalent-_delta Since unnamed_addr indicates that the address is not significant, only the content, we can optimize the case above by replacing pc-relative accesses to "GOT equivalent" globals, by a PC relative access to the GOT entry of the final symbol instead. Therefore, "delta" can contain a pc relative relocation to foo's GOT entry and we avoid the emission of "gotequivalent", yielding the assembly code below: .globl _foo _foo: .long 42 .globl _delta _delta: .long _foo@GOTPCREL+4 There are a couple of advantages of doing this: (1) Front-ends that need to emit a great deal of data to store pointers to external symbols could save space by not emitting such "got equivalent" globals and (2) IR constructs combined with this opt opens a way to represent GOT pcrel relocations by using the LLVM IR, which is something we previously had no way to express. Differential Revision: http://reviews.llvm.org/D6922 rdar://problem/18534217 llvm-svn: 230264		2015-02-23 21:26:18 +00:00
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CostTable.h
Target.td	Add the llvm.frameallocate and llvm.recoverframeallocation intrinsics	2015-01-13 00:48:10 +00:00
TargetCallingConv.h	AArch64: Safely handle the incoming sret call argument.	2015-02-16 18:10:47 +00:00
TargetCallingConv.td	[mips] Remove MipsCC::analyzeCallOperands in favour of CCState::AnalyzeCallOperands. NFC	2014-11-07 11:43:49 +00:00
TargetFrameLowering.h	[X86] Convert esp-relative movs of function arguments to pushes, step 2	2015-02-01 16:56:04 +00:00
TargetInstrInfo.h	Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.	2015-02-15 22:54:22 +00:00
TargetIntrinsicInfo.h	Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.	2015-02-15 22:54:22 +00:00
TargetItinerary.td
TargetLowering.h	Rewrite the global merge pass to be subprogram agnostic for now.	2015-02-23 19:28:45 +00:00
TargetLoweringObjectFile.h	[AsmPrinter] Access pointers to globals via pcrel GOT entries	2015-02-23 21:26:18 +00:00
TargetMachine.h	Make the TargetMachine::getSubtarget that takes a Function argument	2015-02-20 07:32:59 +00:00
TargetOpcodes.h	Add the llvm.frameallocate and llvm.recoverframeallocation intrinsics	2015-01-13 00:48:10 +00:00
TargetOptions.h	Add r228980 back.	2015-02-17 20:48:01 +00:00
TargetRegisterInfo.h	[StackMaps] Allow the target to pre-process the live-out mask	2015-01-13 17:47:59 +00:00
TargetSchedule.td
TargetSelectionDAG.td	Add generic fmad DAG node.	2015-02-20 22:10:33 +00:00
TargetSelectionDAGInfo.h	Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.	2015-02-15 22:54:22 +00:00
TargetSubtargetInfo.h	Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.	2015-02-15 22:54:22 +00:00