[ThinLTO] Fix missing call graph edges for calls with bitcasts.

This change doesn't fix the root cause of the miscompile PR34966 as the root
cause is in the linker ld64. This change makes call graph more complete
allowing to have better module imports/exports.

rdar://problem/35344706

Reviewers: tejohnson

Reviewed By: tejohnson

Subscribers: mehdi_amini, inglorion, eraman, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D39356

llvm-svn: 317853

diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index 82db09c..8d1e7ee 100644 (file)
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -243,6 +243,11 @@ computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
 
       auto *CalledValue = CS.getCalledValue();
       auto *CalledFunction = CS.getCalledFunction();
+      if (CalledValue && !CalledFunction) {
+        CalledValue = CalledValue->stripPointerCastsNoFollowAliases();
+        // Stripping pointer casts can reveal a called function.
+        CalledFunction = dyn_cast<Function>(CalledValue);
+      }
       // Check if this is an alias to a function. If so, get the
       // called aliasee for the checks below.
       if (auto *GA = dyn_cast<GlobalAlias>(CalledValue)) {
@@ -275,9 +280,8 @@ computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
         // Skip inline assembly calls.
         if (CI && CI->isInlineAsm())
           continue;
-        // Skip direct calls.
-        if (!CS.getCalledValue() || isa<Constant>(CS.getCalledValue()))
-          continue;
+        assert(CalledValue && !isa<Constant>(CalledValue) &&
+               "Expected indirect call");
 
         uint32_t NumVals, NumCandidates;
         uint64_t TotalCount;

diff --git a/llvm/test/Bitcode/thinlto-function-summary-callgraph-cast.ll b/llvm/test/Bitcode/thinlto-function-summary-callgraph-cast.ll
new file mode 100644 (file)
index 0000000..b377ba8
--- /dev/null
+++ b/llvm/test/Bitcode/thinlto-function-summary-callgraph-cast.ll
@@ -0,0 +1,31 @@
+; Test to check the callgraph for calls to casts.
+; RUN: opt -module-summary %s -o %t.o
+; RUN: llvm-bcanalyzer -dump %t.o | FileCheck %s
+; PR34966
+
+; CHECK:       <GLOBALVAL_SUMMARY_BLOCK
+; CHECK-NEXT:    <VERSION
+; "op7=1" is a call to "callee" function.
+; CHECK-NEXT:    <PERMODULE {{.*}} op7=1 op8=[[ALIASID:[0-9]+]]/>
+; CHECK-NEXT:    <PERMODULE {{.*}} op0=[[ALIASEEID:[0-9]+]]
+; CHECK-NEXT:    <ALIAS {{.*}} op0=[[ALIASID]] {{.*}} op2=[[ALIASEEID]]/>
+; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
+
+; ModuleID = 'thinlto-function-summary-callgraph-cast.ll'
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @caller() {
+    call void bitcast (void (...)* @callee to void ()*)()
+    call void bitcast (void (...)* @analias to void ()*)()
+    ret void
+}
+
+declare void @callee(...)
+
+@analias = alias void (...), bitcast (void ()* @aliasee to void (...)*)
+
+define void @aliasee() {
+entry:
+    ret void
+}