GC poses hazards to the inliner. Consider:

    define void @f() {
            ...
            call i32 @g()
            ...
    }

    define void @g() {
            ...
    }

The hazards are:

  - @f and @g have GC, but they differ GC. Inlining is invalid. This
    may never occur.
  - @f has no GC, but @g does. g's GC must be propagated to @f.

The other scenarios are safe:

  - @f and @g have the same GC.
  - @f and @g have no GC.
  - @g has no GC.

This patch adds inliner checks for the former two scenarios.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45351 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index dba0e69a35523cb181fc0e9422473d26cd9bc1f3..0a9aa7a8d751fc2fe35590852b950e729ff6412f 100644 (file)
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -201,6 +201,19 @@ bool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD) {
   BasicBlock *OrigBB = TheCall->getParent();
   Function *Caller = OrigBB->getParent();
 
+  
+  // GC poses two hazards to inlining, which only occur when the callee has GC:
+  //  1. If the caller has no GC, then the callee's GC must be propagated to the
+  //     caller.
+  //  2. If the caller has a differing GC, it is invalid to inline.
+  if (CalledFunc->hasCollector()) {
+    if (!Caller->hasCollector())
+      Caller->setCollector(CalledFunc->getCollector());
+    else if (CalledFunc->getCollector() != Caller->getCollector())
+      return false;
+  }
+  
+  
   // Get an iterator to the last basic block in the function, which will have
   // the new function inlined after it.
   //

diff --git a/test/CodeGen/Generic/GC/inline.ll b/test/CodeGen/Generic/GC/inline.ll
new file mode 100644 (file)
index 0000000..157e19d
--- /dev/null
+++ b/test/CodeGen/Generic/GC/inline.ll
@@ -0,0 +1,23 @@
+; RUN: llvm-as < %s | opt -inline | llvm-dis | grep example
+
+       %IntArray = type { i32, [0 x i32*] }
+
+declare void @llvm.gcroot(i8**, i8*) nounwind 
+
+define i32 @f() {
+       %x = call i32 @g( )             ; <i32> [#uses=1]
+       ret i32 %x
+}
+
+define internal i32 @g() gc "example" {
+       %root = alloca i8*              ; <i8**> [#uses=2]
+       call void @llvm.gcroot( i8** %root, i8* null )
+       %obj = call %IntArray* @h( )            ; <%IntArray*> [#uses=2]
+       %obj.2 = bitcast %IntArray* %obj to i8*         ; <i8*> [#uses=1]
+       store i8* %obj.2, i8** %root
+       %Length.ptr = getelementptr %IntArray* %obj, i32 0, i32 0               ; <i32*> [#uses=1]
+       %Length = load i32* %Length.ptr         ; <i32> [#uses=1]
+       ret i32 %Length
+}
+
+declare %IntArray* @h()

diff --git a/test/CodeGen/Generic/GC/inline2.ll b/test/CodeGen/Generic/GC/inline2.ll
new file mode 100644 (file)
index 0000000..b45ef7c
--- /dev/null
+++ b/test/CodeGen/Generic/GC/inline2.ll
@@ -0,0 +1,24 @@
+; RUN: llvm-as < %s | opt -inline | llvm-dis | grep sample
+; RUN: llvm-as < %s | opt -inline | llvm-dis | grep example
+
+       %IntArray = type { i32, [0 x i32*] }
+
+declare void @llvm.gcroot(i8**, i8*) nounwind 
+
+define i32 @f() gc "sample" {
+       %x = call i32 @g( )             ; <i32> [#uses=1]
+       ret i32 %x
+}
+
+define internal i32 @g() gc "example" {
+       %root = alloca i8*              ; <i8**> [#uses=2]
+       call void @llvm.gcroot( i8** %root, i8* null )
+       %obj = call %IntArray* @h( )            ; <%IntArray*> [#uses=2]
+       %obj.2 = bitcast %IntArray* %obj to i8*         ; <i8*> [#uses=1]
+       store i8* %obj.2, i8** %root
+       %Length.ptr = getelementptr %IntArray* %obj, i32 0, i32 0               ; <i32*> [#uses=1]
+       %Length = load i32* %Length.ptr         ; <i32> [#uses=1]
+       ret i32 %Length
+}
+
+declare %IntArray* @h()