[PATCH] D28423: Fix assertions on lazy-loading of Metadata TBAA attachments
Mehdi AMINI via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 6 16:59:37 PST 2017
mehdi_amini created this revision.
mehdi_amini added reviewers: tejohnson, pcc.
mehdi_amini added a subscriber: llvm-commits.
The issue happens with:
%0 = ....., !tbaa !0
%1 = ....., !tbaa !1
With !0 that references !1.
In this case when loading !0 we generates a temporary for the
operand !1. We now flush it immediately and trigger the load of
!1 before moving on. If we don't we get the temporary when
attaching to %1. This is usually not an issue except that we
eagerly try to update TBAA MDNodes, which is obviously not possible
if we only have a temporary.
https://reviews.llvm.org/D28423
Files:
llvm/lib/Bitcode/Reader/MetadataLoader.cpp
llvm/test/ThinLTO/X86/Inputs/funcimport-tbaa.ll
llvm/test/ThinLTO/X86/funcimport-tbaa.ll
Index: llvm/test/ThinLTO/X86/funcimport-tbaa.ll
===================================================================
--- /dev/null
+++ llvm/test/ThinLTO/X86/funcimport-tbaa.ll
@@ -0,0 +1,39 @@
+; We generate invalid TBAA, hence -disable-verify, but this is a convenient way
+; to trigger a metadata lazyloading crash
+
+; RUN: opt -module-summary %s -o %t.bc -bitcode-mdindex-threshold=0 -disable-verify
+; RUN: opt -module-summary %p/Inputs/funcimport-tbaa.ll -o %t2.bc
+; RUN: llvm-lto -thinlto-action=thinlink -o %t3.bc %t.bc %t2.bc
+
+
+; RUN: llvm-lto -thinlto-action=import %t2.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=IMPORTGLOB1
+; IMPORTGLOB1: define available_externally float @globalfunc1
+; IMPORTGLOB1: !tbaa
+; IMPORTGLOB1: !tbaa
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+define float @globalfunc1(i32*, float*) {
+ %3 = load i32, i32* %0, align 4, !tbaa !0
+ %4 = sitofp i32 %3 to float
+ %5 = load float, float* %1, align 4, !tbaa !4
+ %6 = fadd float %4, %5
+ ret float %6
+}
+
+; We need a second function for force the metadata to be emitted in the global block
+define float @globalfunc2(i32*, float*) {
+ %3 = load i32, i32* %0, align 4, !tbaa !0
+ %4 = sitofp i32 %3 to float
+ %5 = load float, float* %1, align 4, !tbaa !4
+ %6 = fadd float %4, %5
+ ret float %6
+}
+
+!0 = !{!1, !4, i64 0}
+!1 = !{!"int", !2, i64 0}
+!2 = !{!"omnipotent char", !3, i64 0}
+!3 = !{!"Simple C/C++ TBAA"}
+!4 = !{!5, !5, i64 0}
+!5 = !{!"float", !2, i64 0}
Index: llvm/test/ThinLTO/X86/Inputs/funcimport-tbaa.ll
===================================================================
--- /dev/null
+++ llvm/test/ThinLTO/X86/Inputs/funcimport-tbaa.ll
@@ -0,0 +1,11 @@
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+
+define i32 @main() {
+entry:
+ %unused = call float @globalfunc1(i32* null, float*null)
+ ret i32 0
+}
+
+declare float @globalfunc1(i32*, float*)
\ No newline at end of file
Index: llvm/lib/Bitcode/Reader/MetadataLoader.cpp
===================================================================
--- llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -1562,17 +1562,14 @@
SmallVector<uint64_t, 64> Record;
- PlaceholderQueue Placeholders;
-
while (true) {
BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
switch (Entry.Kind) {
case BitstreamEntry::SubBlock: // Handled for us already.
case BitstreamEntry::Error:
return error("Malformed block");
case BitstreamEntry::EndBlock:
- resolveForwardRefsAndPlaceholders(Placeholders);
return Error::success();
case BitstreamEntry::Record:
// The interesting case.
@@ -1608,10 +1605,13 @@
auto Idx = Record[i + 1];
if (Idx < (MDStringRef.size() + GlobalMetadataBitPosIndex.size()) &&
- !MetadataList.lookup(Idx))
+ !MetadataList.lookup(Idx)) {
// Load the attachment if it is in the lazy-loadable range and hasn't
// been loaded yet.
+ PlaceholderQueue Placeholders;
lazyLoadOneMetadata(Idx, Placeholders);
+ resolveForwardRefsAndPlaceholders(Placeholders);
+ }
Metadata *Node = MetadataList.getMetadataFwdRef(Idx);
if (isa<LocalAsMetadata>(Node))
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