llvm-mirror/test/Bitcode/metadata-function-blocks.ll
Mehdi Amini 57004ae3ac 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
2016-12-28 22:30:28 +00:00

79 lines
2.2 KiB
LLVM

; RUN: llvm-as < %s -bitcode-mdindex-threshold=0 | llvm-bcanalyzer -dump | FileCheck %s
; Test that metadata only used by a single function is serialized in that
; function instead of in the global pool.
;
; In order to make the bitcode records easy to follow, nodes in this testcase
; are named after the ids they are given in the bitcode. Nodes local to a
; function have offsets of 100 or 200 (depending on the function) so that they
; remain unique within this textual IR.
; Check for strings in the global pool.
; CHECK: <METADATA_BLOCK
; CHECK-NEXT: <STRINGS
; CHECK-SAME: /> num-strings = 3 {
; CHECK-NEXT: 'named'
; CHECK-NEXT: 'named and foo'
; CHECK-NEXT: 'foo and bar'
; CHECK-NEXT: }
; Each node gets a new number. Bottom-up traversal of nodes.
!named = !{!6}
; Before the records we emit an offset to the index for the block
; CHECK-NEXT: <INDEX_OFFSET
; CHECK-NEXT: <NODE op0=1/>
!4 = !{!"named"}
; CHECK-NEXT: <NODE op0=2/>
!5 = !{!"named and foo"}
; CHECK-NEXT: <NODE op0=1 op1=4 op2=5/>
!6 = !{!"named", !4, !5}
; CHECK-NEXT: <NODE op0=3/>
!7 = !{!"foo and bar"}
; CHECK-NOT: <NODE
; CHECK: </METADATA_BLOCK
; Look at metadata local to @foo, starting with strings.
; CHECK: <FUNCTION_BLOCK
; CHECK: <METADATA_BLOCK
; CHECK-NEXT: <STRINGS
; CHECK-SAME: /> num-strings = 1 {
; CHECK-NEXT: 'foo'
; CHECK-NEXT: }
; Function-local nodes start at 9 (strings at 8).
; CHECK-NEXT: <NODE op0=8/>
!109 = !{!"foo"}
; CHECK-NEXT: <NODE op0=8 op1=3 op2=9 op3=7 op4=5/>
!110 = !{!"foo", !"foo and bar", !109, !7, !5}
; CHECK-NEXT: </METADATA_BLOCK
define void @foo() !foo !110 {
unreachable
}
; Look at metadata local to @bar, starting with strings.
; CHECK: <FUNCTION_BLOCK
; CHECK: <METADATA_BLOCK
; CHECK-NEXT: <STRINGS
; CHECK-SAME: /> num-strings = 1 {
; CHECK-NEXT: 'bar'
; CHECK-NEXT: }
; Function-local nodes start at 9 (strings at 8).
; CHECK-NEXT: <NODE op0=8/>
!209 = !{!"bar"}
; CHECK-NEXT: <NODE op0=8 op1=3 op2=9 op3=7/>
!210 = !{!"bar", !"foo and bar", !209, !7}
; CHECK-NEXT: </METADATA_BLOCK
define void @bar() {
unreachable, !bar !210
}