From a9f4cc9510546f5728258524d344a3e03e43500b Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Wed, 7 Sep 2016 16:15:31 +0000
Subject: [codeview] Add new directives to record inlined call site line info

Summary:
Previously we were trying to represent this with the "contains" list of
the .cv_inline_linetable directive, which was not enough information.
Now we directly represent the chain of inlined call sites, so we know
what location to emit when we encounter a .cv_loc directive of an inner
inlined call site while emitting the line table of an outer function or
inlined call site. Fixes PR29146.

Also fixes PR29147, where we would crash when .cv_loc directives crossed
sections. Now we write down the section of the first .cv_loc directive,
and emit an error if any other .cv_loc directive for that function is in
a different section.

Also fixes issues with discontiguous inlined source locations, like in
this example:

  volatile int unlikely_cond = 0;
  extern void __declspec(noreturn) abort();
  __forceinline void f() {
    if (!unlikely_cond) abort();
  }
  int main() {
    unlikely_cond = 0;
    f();
    unlikely_cond = 0;
  }

Previously our tables gave bad location information for the 'abort'
call, and the debugger wouldn't snow the inlined stack frame for 'f'.
It is important to emit good line tables for this code pattern, because
it comes up whenever an asan bug occurs in an inlined function. The
__asan_report* stubs are generally placed after the normal function
epilogue, leading to discontiguous regions of inlined code.

Reviewers: majnemer, amccarth

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D24014

llvm-svn: 280822
---
 llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp | 30 +++++++++++++--------------
 1 file changed, 14 insertions(+), 16 deletions(-)

(limited to 'llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp')

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 63d9a4744a4..51a5d06b954 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -124,7 +124,16 @@ CodeViewDebug::getInlineSite(const DILocation *InlinedAt,
   auto SiteInsertion = CurFn->InlineSites.insert({InlinedAt, InlineSite()});
   InlineSite *Site = &SiteInsertion.first->second;
   if (SiteInsertion.second) {
+    unsigned ParentFuncId = CurFn->FuncId;
+    if (const DILocation *OuterIA = InlinedAt->getInlinedAt())
+      ParentFuncId =
+          getInlineSite(OuterIA, InlinedAt->getScope()->getSubprogram())
+              .SiteFuncId;
+
     Site->SiteFuncId = NextFuncId++;
+    OS.EmitCVInlineSiteIdDirective(
+        Site->SiteFuncId, ParentFuncId, maybeRecordFile(InlinedAt->getFile()),
+        InlinedAt->getLine(), InlinedAt->getColumn(), SMLoc());
     Site->Inlinee = Inlinee;
     InlinedSubprograms.insert(Inlinee);
     getFuncIdForSubprogram(Inlinee);
@@ -357,8 +366,8 @@ void CodeViewDebug::maybeRecordLocation(const DebugLoc &DL,
   }
 
   OS.EmitCVLocDirective(FuncId, FileId, DL.getLine(), DL.getCol(),
-                        /*PrologueEnd=*/false,
-                        /*IsStmt=*/false, DL->getFilename());
+                        /*PrologueEnd=*/false, /*IsStmt=*/false,
+                        DL->getFilename(), SMLoc());
 }
 
 void CodeViewDebug::emitCodeViewMagicVersion() {
@@ -529,17 +538,6 @@ void CodeViewDebug::emitInlineeLinesSubsection() {
   endCVSubsection(InlineEnd);
 }
 
-void CodeViewDebug::collectInlineSiteChildren(
-    SmallVectorImpl<unsigned> &Children, const FunctionInfo &FI,
-    const InlineSite &Site) {
-  for (const DILocation *ChildSiteLoc : Site.ChildSites) {
-    auto I = FI.InlineSites.find(ChildSiteLoc);
-    const InlineSite &ChildSite = I->second;
-    Children.push_back(ChildSite.SiteFuncId);
-    collectInlineSiteChildren(Children, FI, ChildSite);
-  }
-}
-
 void CodeViewDebug::emitInlinedCallSite(const FunctionInfo &FI,
                                         const DILocation *InlinedAt,
                                         const InlineSite &Site) {
@@ -565,11 +563,9 @@ void CodeViewDebug::emitInlinedCallSite(const FunctionInfo &FI,
 
   unsigned FileId = maybeRecordFile(Site.Inlinee->getFile());
   unsigned StartLineNum = Site.Inlinee->getLine();
-  SmallVector<unsigned, 3> SecondaryFuncIds;
-  collectInlineSiteChildren(SecondaryFuncIds, FI, Site);
 
   OS.EmitCVInlineLinetableDirective(Site.SiteFuncId, FileId, StartLineNum,
-                                    FI.Begin, FI.End, SecondaryFuncIds);
+                                    FI.Begin, FI.End);
 
   OS.EmitLabel(InlineEnd);
 
@@ -877,6 +873,8 @@ void CodeViewDebug::beginFunction(const MachineFunction *MF) {
   CurFn->FuncId = NextFuncId++;
   CurFn->Begin = Asm->getFunctionBegin();
 
+  OS.EmitCVFuncIdDirective(CurFn->FuncId);
+
   // Find the end of the function prolog.  First known non-DBG_VALUE and
   // non-frame setup location marks the beginning of the function body.
   // FIXME: is there a simpler a way to do this? Can we just search
-- 
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