r230460 - Produce less broken basic block sequences for __finally blocks.

[NAKAMURA Takumi]

The test was failing with -Asserts.

--- a/clang/test/CodeGen/exceptions-seh-finally.c
+++ b/clang/test/CodeGen/exceptions-seh-finally.c
@@ -189,12 +189,12 @@ int nested___finally___finally() {
   return 0;
 }
 // CHECK-LABEL: define i32 @nested___finally___finally
-// CHECK: store i8 0, i8* %
+// CHECK: store i8 0, i8* [[ABT:%.+]]
 // CHECK-NEXT: br label %[[finally:[^ ]*]]
 //
 // CHECK: [[finally]]
-// CHECK-NEXT:  store i32 1, i32* %cleanup.dest.slot
-// CHECK-NEXT:  store i8 0, i8* %abnormal.termination.slot
+// CHECK-NEXT:  store i32 1, i32* %
+// CHECK-NEXT:  store i8 0, i8* [[ABT]]
 // CHECK-NEXT: br label %[[outerfinally:[^ ]*]]
 //
 // CHECK: [[outerfinally]]

2015-02-25 19:06 GMT+09:00 Daniel Jasper <djasper at google.com>:
> This is breaking tests on buildbots:
> http://lab.llvm.org:8080/green/job/clang-stage2-configure-Rlto_check/2279/
>
> Rolling back.
>
> On Wed, Feb 25, 2015 at 5:05 AM, Nico Weber <nicolasweber at gmx.de> wrote:
>>
>> Author: nico
>> Date: Tue Feb 24 22:05:18 2015
>> New Revision: 230460
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=230460&view=rev
>> Log:
>> Produce less broken basic block sequences for __finally blocks.
>>
>> The way cleanups (such as PerformSEHFinally) get emitted is that codegen
>> generates some initialization code, then calls the cleanup's Emit() with
>> the
>> insertion point set to a good place, then the cleanup is supposed to emit
>> its
>> stuff, and then codegen might tack in a jump or similar to where the
>> insertion
>> point is after the cleanup.
>>
>> The PerformSEHFinally cleanup tries to just stash away the block it's
>> supposed
>> to codegen into, and then does codegen later, into that stashed block.
>> However,
>> after codegen'ing the __finally block, it used to set the insertion point
>> to
>> the finally's continuation block (where the __finally cleanup goes when
>> its body
>> is completed after regular, non-exceptional control flow).  That's not
>> correct,
>> as that block can (and generally does) already ends in a jump.  Instead,
>> remember the insertion point that was current before the __finally got
>> emitted,
>> and restore that.
>>
>> Fixes two of the crashes in PR22553.
>>
>> Modified:
>>     cfe/trunk/lib/CodeGen/CGException.cpp
>>     cfe/trunk/test/CodeGen/exceptions-seh-finally.c
>>
>> Modified: cfe/trunk/lib/CodeGen/CGException.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGException.cpp?rev=230460&r1=230459&r2=230460&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/CGException.cpp (original)
>> +++ cfe/trunk/lib/CodeGen/CGException.cpp Tue Feb 24 22:05:18 2015
>> @@ -813,8 +813,8 @@ llvm::BasicBlock *CodeGenFunction::EmitL
>>    bool hasFilter = false;
>>    SmallVector<llvm::Value*, 4> filterTypes;
>>    llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
>> -  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end();
>> -         I != E; ++I) {
>> +  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I
>> != E;
>> +       ++I) {
>>
>>      switch (I->getKind()) {
>>      case EHScope::Cleanup:
>> @@ -1927,6 +1927,7 @@ void CodeGenFunction::ExitSEHTryStmt(con
>>      assert(FI.ContBB && "did not emit normal cleanup");
>>
>>      // Emit the code into FinallyBB.
>> +    CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
>>      Builder.SetInsertPoint(FI.FinallyBB);
>>      EmitStmt(Finally->getBlock());
>>
>> @@ -1949,7 +1950,7 @@ void CodeGenFunction::ExitSEHTryStmt(con
>>        Builder.CreateBr(FI.ContBB);
>>      }
>>
>> -    Builder.SetInsertPoint(FI.ContBB);
>> +    Builder.restoreIP(SavedIP);
>>
>>      return;
>>    }
>>
>> Modified: cfe/trunk/test/CodeGen/exceptions-seh-finally.c
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/exceptions-seh-finally.c?rev=230460&r1=230459&r2=230460&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/CodeGen/exceptions-seh-finally.c (original)
>> +++ cfe/trunk/test/CodeGen/exceptions-seh-finally.c Tue Feb 24 22:05:18
>> 2015
>> @@ -160,3 +160,45 @@ void noreturn_finally() {
>>  // CHECK-NEXT: cleanup
>>  // CHECK: store i8 1, i8* %
>>  // CHECK: br label %[[finally]]
>> +
>> +int finally_with_return() {
>> +  __try {
>> +    return 42;
>> +  } __finally {
>> +  }
>> +}
>> +// CHECK-LABEL: define i32 @finally_with_return()
>> +// CHECK: store i8 0, i8* %
>> +// CHECK-NEXT: br label %[[finally:[^ ]*]]
>> +//
>> +// CHECK: [[finally]]
>> +// CHECK-NEXT: br label %[[finallycont:[^ ]*]]
>> +//
>> +// CHECK: [[finallycont]]
>> +// CHECK-NEXT: ret i32 42
>> +
>> +int nested___finally___finally() {
>> +  __try {
>> +    __try {
>> +    } __finally {
>> +      return 1;
>> +    }
>> +  } __finally {
>> +    // Intentionally no return here.
>> +  }
>> +  return 0;
>> +}
>> +// CHECK-LABEL: define i32 @nested___finally___finally
>> +// CHECK: store i8 0, i8* %
>> +// CHECK-NEXT: br label %[[finally:[^ ]*]]
>> +//
>> +// CHECK: [[finally]]
>> +// CHECK-NEXT:  store i32 1, i32* %cleanup.dest.slot
>> +// CHECK-NEXT:  store i8 0, i8* %abnormal.termination.slot
>> +// CHECK-NEXT: br label %[[outerfinally:[^ ]*]]
>> +//
>> +// CHECK: [[outerfinally]]
>> +// CHECK-NEXT: br label %[[finallycont:[^ ]*]]
>> +//
>> +// CHECK: [[finallycont]]
>> +// CHECK-NEXT: ret i32 1
>>
>>
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