[PATCH] D39356: [ThinLTO] Fix missing call graph edges for calls with bitcasts.

[Volodymyr Sapsai via Phabricator via llvm-commits]

vsapsai created this revision.
Herald added subscribers: hiraditya, eraman, inglorion, mehdi_amini.

Fixes PR34966 as added call graph edges allow to build correct module
imports/exports. With fixed imports/exports ThinLTO can see which
functions are used and keeps both static and non-static functions as
both of them are used.

rdar://problem/35099885


https://reviews.llvm.org/D39356

Files:
  llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
  llvm/test/Bitcode/thinlto-function-summary-callgraph-cast.ll


Index: llvm/test/Bitcode/thinlto-function-summary-callgraph-cast.ll
===================================================================
--- /dev/null
+++ 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(...)
+
+ at analias = alias void (...), bitcast (void ()* @aliasee to void (...)*)
+
+define void @aliasee() {
+entry:
+    ret void
+}
Index: llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -243,6 +243,12 @@
 
       auto *CalledValue = CS.getCalledValue();
       auto *CalledFunction = CS.getCalledFunction();
+      if (CalledValue) {
+        CalledValue = CalledValue->stripPointerCastsNoFollowAliases();
+        // Stripping pointer casts can reveal a called function.
+        if (!CalledFunction)
+          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)) {
@@ -276,7 +282,7 @@
         if (CI && CI->isInlineAsm())
           continue;
         // Skip direct calls.
-        if (!CS.getCalledValue() || isa<Constant>(CS.getCalledValue()))
+        if (!CalledValue || isa<Constant>(CalledValue))
           continue;
 
         uint32_t NumVals, NumCandidates;


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