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Add an index for Module Metadata record in the bitcode This index record the position for each metadata record in the bitcode, so that the reader will be able to lazy-load on demand each individual record. We also make sure that every abbrev is emitted upfront so that the block can be skipped while reading. I don't plan to commit this before having the reader counterpart, but I figured this can be reviewed mostly independently. Recommit r290684 (was reverted in r290686 because a test was broken) after adding a threshold to avoid emitting the index when unnecessary (little amount of metadata). This optimization "hides" a limitation of the ability to backpatch in the bitstream: we can only backpatch safely when the position has been flushed. So if we emit an index for one metadata, it is possible that (part of) the offset placeholder hasn't been flushed and the backpatch will fail. Differential Revision: https://reviews.llvm.org/D28083 llvm-svn: 290690
2016-12-29 06:30:28 +08:00
; RUN: llvm-as <%s -bitcode-mdindex-threshold=0 | llvm-bcanalyzer -dump | FileCheck %s
BitcodeWriter: Emit distinct nodes before uniqued nodes When an operand of a distinct node hasn't been read yet, the reader can use a DistinctMDOperandPlaceholder. This is much cheaper than forward referencing from a uniqued node. Change ValueEnumerator::organizeMetadata to partition distinct nodes and uniqued nodes to reduce the overhead of cycles broken by distinct nodes. Mehdi measured this for me; this removes most of the RAUW from the importing step of -flto=thin, even after a WIP patch that removes string-based DITypeRefs (introducing many more cycles to the metadata graph). llvm-svn: 267276
2016-04-23 12:42:39 +08:00
; Check that distinct nodes are emitted before uniqued nodes, even if that
; breaks post-order traversals.
; Nodes in this testcase are numbered to match how they are referenced in
; bitcode. !1 is referenced as opN=1.
; CHECK: <DISTINCT_NODE op0=2/>
!1 = distinct !{!2}
; CHECK-NEXT: <NODE op0=1/>
!2 = !{!1}
Add an index for Module Metadata record in the bitcode This index record the position for each metadata record in the bitcode, so that the reader will be able to lazy-load on demand each individual record. We also make sure that every abbrev is emitted upfront so that the block can be skipped while reading. I don't plan to commit this before having the reader counterpart, but I figured this can be reviewed mostly independently. Recommit r290684 (was reverted in r290686 because a test was broken) after adding a threshold to avoid emitting the index when unnecessary (little amount of metadata). This optimization "hides" a limitation of the ability to backpatch in the bitstream: we can only backpatch safely when the position has been flushed. So if we emit an index for one metadata, it is possible that (part of) the offset placeholder hasn't been flushed and the backpatch will fail. Differential Revision: https://reviews.llvm.org/D28083 llvm-svn: 290690
2016-12-29 06:30:28 +08:00
; Before the named records we emit the index containing the position of the
; previously emitted records
; CHECK-NEXT: <INDEX {{.*}} (offset match)
BitcodeWriter: Emit distinct nodes before uniqued nodes When an operand of a distinct node hasn't been read yet, the reader can use a DistinctMDOperandPlaceholder. This is much cheaper than forward referencing from a uniqued node. Change ValueEnumerator::organizeMetadata to partition distinct nodes and uniqued nodes to reduce the overhead of cycles broken by distinct nodes. Mehdi measured this for me; this removes most of the RAUW from the importing step of -flto=thin, even after a WIP patch that removes string-based DITypeRefs (introducing many more cycles to the metadata graph). llvm-svn: 267276
2016-04-23 12:42:39 +08:00
; Note: named metadata nodes are not cannot reference null so their operands
; are numbered off-by-one.
; CHECK-NEXT: <NAME
; CHECK-NEXT: <NAMED_NODE op0=1/>
!named = !{!2}