[llvm] r278371 - Improve virtual register handling when computing debug information
Dominic Chen via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 11 10:52:41 PDT 2016
Author: ddcc
Date: Thu Aug 11 12:52:40 2016
New Revision: 278371
URL: http://llvm.org/viewvc/llvm-project?rev=278371&view=rev
Log:
Improve virtual register handling when computing debug information
Summary: Some backends, like WebAssembly, use virtual registers instead of physical registers. This crashes the DbgValueHistoryCalculator pass, which assumes that all registers are physical. Instead, skip virtual registers when iterating aliases, and assume that they are clobbered.
Reviewers: dexonsmith, dschuff, aprantl
Subscribers: yurydelendik, llvm-commits, jfb, sunfish
Differential Revision: https://reviews.llvm.org/D22590
Added:
llvm/trunk/test/CodeGen/WebAssembly/dbgvalue.ll
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp?rev=278371&r1=278370&r2=278371&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.cpp Thu Aug 11 12:52:40 2016
@@ -31,7 +31,7 @@ static unsigned isDescribedByReg(const M
assert(MI.isDebugValue());
assert(MI.getNumOperands() == 4);
// If location of variable is described using a register (directly or
- // indirecltly), this register is always a first operand.
+ // indirectly), this register is always a first operand.
return MI.getOperand(0).isReg() ? MI.getOperand(0).getReg() : 0;
}
@@ -164,7 +164,9 @@ static void collectChangingRegs(const Ma
// Look for register defs and register masks. Register masks are
// typically on calls and they clobber everything not in the mask.
for (const MachineOperand &MO : MI.operands()) {
- if (MO.isReg() && MO.isDef() && MO.getReg()) {
+ // Skip virtual registers since they are handled by the parent.
+ if (MO.isReg() && MO.isDef() && MO.getReg() &&
+ !TRI->isVirtualRegister(MO.getReg())) {
for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
++AI)
Regs.set(*AI);
@@ -192,12 +194,18 @@ void llvm::calculateDbgValueHistory(cons
// some variables.
for (const MachineOperand &MO : MI.operands()) {
if (MO.isReg() && MO.isDef() && MO.getReg()) {
+ // If this is a virtual register, only clobber it since it doesn't
+ // have aliases.
+ if (TRI->isVirtualRegister(MO.getReg()))
+ clobberRegisterUses(RegVars, MO.getReg(), Result, MI);
// If this is a register def operand, it may end a debug value
// range.
- for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
- ++AI)
- if (ChangingRegs.test(*AI))
- clobberRegisterUses(RegVars, *AI, Result, MI);
+ else {
+ for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
+ ++AI)
+ if (ChangingRegs.test(*AI))
+ clobberRegisterUses(RegVars, *AI, Result, MI);
+ }
} else if (MO.isRegMask()) {
// If this is a register mask operand, clobber all debug values in
// non-CSRs.
@@ -238,7 +246,8 @@ void llvm::calculateDbgValueHistory(cons
if (!MBB.empty() && &MBB != &MF->back()) {
for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {
auto CurElem = I++; // CurElem can be erased below.
- if (ChangingRegs.test(CurElem->first))
+ if (TRI->isVirtualRegister(CurElem->first) ||
+ ChangingRegs.test(CurElem->first))
clobberRegisterUses(RegVars, CurElem, Result, MBB.back());
}
}
Added: llvm/trunk/test/CodeGen/WebAssembly/dbgvalue.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/dbgvalue.ll?rev=278371&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/dbgvalue.ll (added)
+++ llvm/trunk/test/CodeGen/WebAssembly/dbgvalue.ll Thu Aug 11 12:52:40 2016
@@ -0,0 +1,69 @@
+; RUN: llc < %s -O0 -verify-machineinstrs -mtriple=wasm32-unknown-unknown | FileCheck %s
+; CHECK: BB#0
+; CHECK: #DEBUG_VALUE: usage:self <- %vreg4
+; CHECK: BB#1
+; CHECK: DW_TAG_variable
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+%0 = type opaque
+
+ at key = external local_unnamed_addr global [15 x i8], align 1
+ at .str = external unnamed_addr constant [33 x i8], align 1
+
+; Function Attrs: nounwind
+define internal i32 @0(i8*) local_unnamed_addr !dbg !14 !type !22 {
+ tail call void @llvm.dbg.value(metadata i8* %0, i64 0, metadata !21, metadata !23), !dbg !24
+ %2 = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([33 x i8], [33 x i8]* @.str, i32 0, i32 0), i8* %0), !dbg !25
+ br i1 1, label %a, label %b
+a:
+ %3 = add i32 %2, %2
+ br label %c
+
+b:
+ %4 = sub i32 %2, %2
+ br label %c
+
+c:
+ %5 = phi i32 [ %3, %a ], [ %4, %b ]
+ %6 = add i32 ptrtoint (i32 (i8*)* @0 to i32), %5
+ ret i32 %6, !dbg !26
+}
+
+; Function Attrs: nounwind
+declare i32 @printf(i8* nocapture readonly, ...) local_unnamed_addr
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!11, !12}
+!llvm.ident = !{!13}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 273884) (llvm/trunk 273897)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
+!1 = !DIFile(filename: "crash.c", directory: "wasm/tests")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DIGlobalVariable(name: "key", scope: !0, file: !1, line: 7, type: !5, isLocal: false, isDefinition: true, variable: [15 x i8]* @key)
+!5 = !DICompositeType(tag: DW_TAG_array_type, baseType: !6, size: 120, align: 8, elements: !9)
+!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "uint8_t", file: !7, line: 185, baseType: !8)
+!7 = !DIFile(filename: "wasm/emscripten/system/include/libc/bits/alltypes.h", directory: "wasm/tests")
+!8 = !DIBasicType(name: "unsigned char", size: 8, align: 8, encoding: DW_ATE_unsigned_char)
+!9 = !{!10}
+!10 = !DISubrange(count: 15)
+!11 = !{i32 2, !"Dwarf Version", i32 4}
+!12 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = !{!"clang version 3.9.0 (trunk 273884) (llvm/trunk 273897)"}
+!14 = distinct !DISubprogram(name: "usage", scope: !1, file: !1, line: 15, type: !15, isLocal: false, isDefinition: true, scopeLine: 15, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !20)
+!15 = !DISubroutineType(types: !16)
+!16 = !{!17, !18}
+!17 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 32, align: 32)
+!19 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
+!20 = !{!21}
+!21 = !DILocalVariable(name: "self", arg: 1, scope: !14, file: !1, line: 15, type: !18)
+!22 = !{i64 0, !"_ZTSFiPcE"}
+!23 = !DIExpression()
+!24 = !DILocation(line: 15, column: 17, scope: !14)
+!25 = !DILocation(line: 16, column: 3, scope: !14)
+!26 = !DILocation(line: 17, column: 3, scope: !14)
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