Add support for string constructors to the interpreter #115914

kg · 2025-05-22T22:26:28Z

No description provided.

Copilot

Pull Request Overview

This PR adds support for string constructors in the interpreter and updates the associated call stub generation.

Added a new test case (TestStringCtor) to verify string constructor functionality
Updated interpreter execution logic to correctly handle fcalls for string constructors
Adjusted call stub generation to account for special string constructors

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/tests/JIT/interpreter/Interpreter.cs	Added test method for string constructor support
src/coreclr/vm/interpexec.cpp	Updated interpreter method call to support special string constructors
src/coreclr/vm/callstubgenerator.cpp	Modified call stub generation for special constructor handling

Copilot · 2025-05-22T22:26:59Z

src/coreclr/vm/interpexec.cpp

@@ -1186,15 +1186,46 @@ void InterpExecMethod(InterpreterFrame *pInterpreterFrame, InterpMethodContextFr
                    callArgsOffset = ip[2];
                    methodSlot = ip[3];

-                    OBJECTREF objRef = AllocateObject((MethodTable*)pMethod->pDataItems[ip[4]]);
+                    MethodTable *pClass = (MethodTable*)pMethod->pDataItems[ip[4]];
+                    // FIXME: Duplicated code from CALL_INTERP_SLOT


Consider refactoring the duplicated code block for handling string constructor invocations to improve maintainability.

Suggested change

// FIXME: Duplicated code from CALL_INTERP_SLOT

src/coreclr/vm/callstubgenerator.cpp

dotnet-policy-service · 2025-05-22T22:27:11Z

Tagging subscribers to this area: @dotnet/interop-contrib
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src/coreclr/vm/callstubgenerator.cpp

Co-authored-by: Aaron Robinson <[email protected]>

kg · 2025-05-23T00:06:30Z

Anyone know what's up with this crossdac failure on CI?

  [458/464] Linking CXX static library unwinder\unwinder_dac.lib
  [459/464] Building RC object dlls\mscordbi\CMakeFiles\mscordbi.dir\Native.rc.res
  [460/464] Building C object D:\a\_work\1\s\artifacts\obj\external\libunwind\CMakeFiles\libunwind_xdac.dir\D_\a\_work\1\s\src\native\external\libunwind\src\dwarf\Gparser.c.obj
  FAILED: D:/a/_work/1/s/artifacts/obj/external/libunwind/CMakeFiles/libunwind_xdac.dir/D_/a/_work/1/s/src/native/external/libunwind/src/dwarf/Gparser.c.obj 
  C:\PROGRA~1\MICROS~1\2022\ENTERP~1\VC\Tools\MSVC\1443~1.348\bin\Hostx64\x64\cl.exe  /nologo -DBUILDENV_CHECKED=1 -DCROSS_COMPILE -DDEBUG -DDISABLE_CONTRACTS -DHAVE_CONFIG_H=1 -DHAVE_DL_ITERATE_PHDR=1 -DHAVE_UNW_GET_ACCESSORS -DHAVE___THREAD=0 -DHOST_64BIT -DHOST_AMD64 -DHOST_WINDOWS -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_STRING=\"\" -DTARGET_64BIT -DTARGET_AMD64 -DTARGET_LINUX -DTARGET_UNIX -DUNW_REMOTE_ONLY -DURTBLDENV_FRIENDLY=Checked -D_CRT_DECLARE_NONSTDC_NAMES -D_CRT_SECURE_NO_WARNINGS -D_DBG -D_DEBUG -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -D_TIME_BITS=64 -D_Thread_local="" -D__amd64__ -D__linux__ -D__x86_64__ -ID:\a\_work\1\s\artifacts\obj\external\libunwind -ID:\a\_work\1\s\src\native\external\libunwind_extras -ID:\a\_work\1\s\src\native -ID:\a\_work\1\s\src\native\inc -ID:\a\_work\1\s\src\native\external\libunwind\include\tdep -ID:\a\_work\1\s\src\native\external\libunwind\include -ID:\a\_work\1\s\artifacts\obj\external\libunwind\include\tdep -ID:\a\_work\1\s\artifacts\obj\external\libunwind\include -ID:\a\_work\1\s\src\native\external\libunwind\include\remote -ID:\a\_work\1\s\src\native\external\libunwind\include\remote\win -ID:\a\_work\1\s\src\native\external\libunwind\src /DWIN32 /D_WINDOWS -std:c11 -MTd /O2 /nologo /W4 /WX /Oi /Oy- /Gm- /Zp8 /Gy /GS /fp:precise /FC /MP /Zm200 /Zc:strictStrings /Zc:wchar_t /Zc:inline /Zc:forScope /wd4065 /wd4100 /wd4127 /wd4131 /wd4189 /wd4200 /wd4201 /wd4206 /wd4239 /wd4245 /wd4291 /wd4310 /wd4324 /wd4366 /wd4456 /wd4457 /wd4458 /wd4459 /wd4463 /wd4505 /wd4702 /wd4706 /wd4733 /wd4815 /wd4838 /wd4918 /wd4960 /wd4961 /wd5105 /wd5205 /we4007 /we4013 /we4102 /we4551 /we4640 /we4806 /we4055 /we4146 /we4242 /we4244 /we4267 /we4302 /we4308 /we4509 /we4510 /we4532 /we4533 /we4610 /we4611 /we4700 /we4701 /we4703 /we4789 /we4995 /we4996 /w34092 /w34121 /w34125 /w34130 /w34132 /w34212 /w34530 /w35038 /w44177 /Zi /ZH:SHA_256 /source-charset:utf-8 /guard:cf /guard:ehcont /permissive- -wd4068 -wd4334 -wd4311 -wd4475 -wd4477 /TC /showIncludes /FoD:\a\_work\1\s\artifacts\obj\external\libunwind\CMakeFiles\libunwind_xdac.dir\D_\a\_work\1\s\src\native\external\libunwind\src\dwarf\Gparser.c.obj /FdD:\a\_work\1\s\artifacts\obj\external\libunwind\CMakeFiles\libunwind_xdac.dir\ /FS -c D:\a\_work\1\s\src\native\external\libunwind\src\dwarf\Gparser.c
  D:\a\_work\1\s\src\native\external\libunwind\src\dwarf\Gparser.c(1181): fatal error C1090: PDB API call failed, error code '23': (0x00000005)
  [461/464] Building CXX object dlls\mscordbi\CMakeFiles\mscordbi.dir\mscordbi.cpp.obj
  ninja: build stopped: subcommand failed.
##[error]BUILD: Error: native component build failed. Refer to the build log files for details.

EDIT: Looks like https://developercommunity.visualstudio.com/t/C1090-PDB-API-call-failed-error-code-2/48897

jkotas · 2025-05-23T00:19:04Z

Also tracked here: #48070 . Build analysis should flag it for you.

jkotas · 2025-05-23T00:55:36Z

src/coreclr/vm/interpexec.cpp

+                    //  fcall that is basically a static method that returns the new instance.
+                    if (pMD && pClass->HasComponentSize())
+                    {
+                        // The compiler didn't know about this so it reserved space for a this-reference. We need to skip


This sounds like a temporary workaround. The compiler can know about this (by checking CORINFO_FLG_VAROBJSIZE flag). What needs to happen to move this logic to the compiler?

m_compHnd didn't appear to expose the things I needed to determine this. I can take another look.

That's the flag CORINFO_FLG_VAROBJSIZE that @jkotas mentioned offline yesterday:

runtime/src/coreclr/jit/importercalls.cpp

Lines 1010 to 1026 in fc85a87

if (opcode == CEE_NEWOBJ)

{

if (clsFlags & CORINFO_FLG_VAROBJSIZE)

{

assert(!(clsFlags & CORINFO_FLG_ARRAY)); // arrays handled separately

// This is a 'new' of a variable sized object, wher

// the constructor is to return the object. In this case

// the constructor claims to return VOID but we know it

// actually returns the new object

assert(callRetTyp == TYP_VOID);

callRetTyp = TYP_REF;

call->gtType = TYP_REF;

impSpillSpecialSideEff();

impPushOnStack(call, typeInfo(clsHnd));

}

else

You can get it by getClassAttribs or by the getCallInfo in the CORINFO_CALL_INFO::classFlags.

janvorli · 2025-05-23T08:30:37Z

src/coreclr/vm/callstubgenerator.cpp

@@ -547,7 +547,14 @@ CallStubHeader *CallStubGenerator::GenerateCallStub(MethodDesc *pMD, AllocMemTra

    _ASSERTE(pMD != NULL);

+    // Classes like System.String have special constructors that are fcalls. When invoking these, we need to override
+    //  HasThis (there's no thisref) and the return type (the return value is the new instance, not void).
+    bool isSpecialConstructor = pMD->IsCtor() && pMD->GetMethodTable()->HasComponentSize();


The runtime uses a bit different condition to decide whether to clear the HasThis, it would be good to use the same one:

runtime/src/coreclr/vm/frames.cpp

Line 1518 in 87b35f4

bool fCtorOfVariableSizedObject = msig.HasThis() && (pFunction->GetMethodTable() == g_pStringClass) && pFunction->IsCtor();

Add support for string constructors to the interpreter

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Copilot AI review requested due to automatic review settings May 22, 2025 22:26

kg requested review from BrzVlad and janvorli as code owners May 22, 2025 22:26

github-actions bot added the area-Interop-coreclr label May 22, 2025

dotnet-policy-service bot assigned kg May 22, 2025

Copilot AI reviewed May 22, 2025

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AaronRobinsonMSFT reviewed May 22, 2025

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src/coreclr/vm/callstubgenerator.cpp Outdated Show resolved Hide resolved

Update src/coreclr/vm/callstubgenerator.cpp

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Co-authored-by: Aaron Robinson <[email protected]>

kg mentioned this pull request May 22, 2025

Add multi-dim array support to the interpreter #115916

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Add support for string constructors to the interpreter #115914

Add support for string constructors to the interpreter #115914

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kg commented May 23, 2025 •

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	if (opcode == CEE_NEWOBJ)
	{
	if (clsFlags & CORINFO_FLG_VAROBJSIZE)
	{
	assert(!(clsFlags & CORINFO_FLG_ARRAY)); // arrays handled separately
	// This is a 'new' of a variable sized object, wher
	// the constructor is to return the object. In this case
	// the constructor claims to return VOID but we know it
	// actually returns the new object
	assert(callRetTyp == TYP_VOID);
	callRetTyp = TYP_REF;
	call->gtType = TYP_REF;
	impSpillSpecialSideEff();

	impPushOnStack(call, typeInfo(clsHnd));
	}
	else

Add support for string constructors to the interpreter #115914

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Add support for string constructors to the interpreter #115914

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Pull Request Overview

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