Fix SamplePGO segfault when debug info is missing.

When emitting a remark for a conditional branch annotation, the remark
uses the line location information of the conditional branch in the
message.  In some cases, that information is unavailable and the
optimization would segfaul. I'm still not sure whether this is a bug or
WAI, but the optimizer should not die because of this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251420 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/IPO/SampleProfile.cpp b/lib/Transforms/IPO/SampleProfile.cpp
index 6ab73450d16ef242c9308d93d1cbdca26e3fff53..d8f8eb8b1a34021c7cefc8eddbd76a269a198c93 100644 (file)
--- a/lib/Transforms/IPO/SampleProfile.cpp
+++ b/lib/Transforms/IPO/SampleProfile.cpp
@@ -780,8 +780,10 @@ void SampleProfileLoader::propagateWeights(Function &F) {
       emitOptimizationRemark(
           Ctx, DEBUG_TYPE, F, MaxDestLoc,
           Twine("most popular destination for conditional branches at ") +
-              BranchLoc->getFilename() + ":" + Twine(BranchLoc.getLine()) +
-              ":" + Twine(BranchLoc.getCol()));
+              ((BranchLoc) ? Twine(BranchLoc->getFilename() + ":" +
+                                   Twine(BranchLoc.getLine()) + ":" +
+                                   Twine(BranchLoc.getCol()))
+                           : Twine("<UNKNOWN LOCATION>")));
     } else {
       DEBUG(dbgs() << "SKIPPED. All branch weights are zero.\n");
     }

diff --git a/test/Transforms/SampleProfile/Inputs/nolocinfo.prof b/test/Transforms/SampleProfile/Inputs/nolocinfo.prof
new file mode 100644 (file)
index 0000000..fc69aa8
--- /dev/null
+++ b/test/Transforms/SampleProfile/Inputs/nolocinfo.prof
@@ -0,0 +1,3 @@
+foo:30000:100
+ 2: 28000
+ 3: 1000

diff --git a/test/Transforms/SampleProfile/nolocinfo.ll b/test/Transforms/SampleProfile/nolocinfo.ll
new file mode 100644 (file)
index 0000000..d700e5f
--- /dev/null
+++ b/test/Transforms/SampleProfile/nolocinfo.ll
@@ -0,0 +1,38 @@
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/nolocinfo.prof -S -pass-remarks=sample-profile 2>&1 | FileCheck %s
+
+define i32 @foo(i32 %i)  {
+entry:
+  %i.addr = alloca i32, align 4
+  %0 = load i32, i32* %i.addr, align 4
+  %cmp = icmp sgt i32 %0, 1000
+
+; Remarks for conditional branches need debug location information for the
+; referring branch. When that is not present, the compiler should not abort.
+;
+; CHECK: remark: nolocinfo.c:3:5: most popular destination for conditional branches at <UNKNOWN LOCATION>
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+  ret i32 0, !dbg !18
+
+if.end:
+  ret i32 1
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9}
+!llvm.ident = !{!10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.8.0 (trunk 251335) (llvm/trunk 251344)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "nolocinfo.c", directory: ".")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, function: i32 (i32)* @foo, variables: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{!7, !7}
+!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 2, !"Debug Info Version", i32 3}
+!10 = !{!"clang version 3.8.0 (trunk 251335) (llvm/trunk 251344)"}
+!15 = distinct !DILexicalBlock(scope: !4, file: !1, line: 2, column: 7)
+!18 = !DILocation(line: 3, column: 5, scope: !15)