Add patch for runtime ilasm generation fix

patches/runtime/0029-Fix-issue-44646-ILAsm-incorrectly-handles-method-.cu.patch

@@ -0,0 +1,152 @@
+From 874540a2205e227c1ccb8a08b4e50789de7611eb Mon Sep 17 00:00:00 2001
+From: Brian Sullivan <briansul@microsoft.com>
+Date: Tue, 17 Nov 2020 14:11:55 -0800
+Subject: [PATCH] Fix issue 44646 - ILAsm incorrectly handles method .custom
+ attribute when we have generic type constraint
+
+The IL Assembler incorrectly dropped a .custom attribute for the method
+This only occurred when the inline syntax for generic type parameters was used in the method definition.
+This behavior can also occur for a generic class definition.
+---
+ src/coreclr/src/ilasm/assembler.cpp | 48 +++++++++++++++++++++++++++++--------
+ src/coreclr/src/ilasm/assembler.h   |  2 +-
+ src/coreclr/src/ilasm/method.cpp    |  7 +++++-
+ 3 files changed, 45 insertions(+), 12 deletions(-)
+
+diff --git a/src/coreclr/src/ilasm/assembler.cpp b/src/coreclr/src/ilasm/assembler.cpp
+index 9748bf7..d6acf8e 100644
+--- a/src/coreclr/src/ilasm/assembler.cpp
++++ b/src/coreclr/src/ilasm/assembler.cpp
+@@ -2487,6 +2487,10 @@ BOOL Assembler::IsPortablePdb()
+     return (m_pdbFormat == PORTABLE) && (m_pPortablePdbWriter != NULL);
+ }
+
++// This method is called after we have parsed the generic type parameters for either
++// a generic class or a generic method.  It calls CheckAddGenericParamConstraint on
++// each generic parameter constraint that was recorded.
++//
+ void Assembler::RecordTypeConstraints(GenericParamConstraintList* pGPCList, int numTyPars, TyParDescr* tyPars)
+ {
+     if (numTyPars > 0)
+@@ -2503,13 +2507,18 @@ void Assembler::RecordTypeConstraints(GenericParamConstraintList* pGPCList, int
+                 for (int j = 0; j < numConstraints; j++)
+                 {
+                     mdToken tkTypeConstraint = ptk[j];
+-                    CheckAddGenericParamConstraint(pGPCList, i, tkTypeConstraint);
++
++                    // pass false for isParamDirective, these constraints are from the class or method definition
++                    //
++                    CheckAddGenericParamConstraint(pGPCList, i, tkTypeConstraint, false);
+                 }
+             }
+         }
+     }
+ }
+
++// AddGenericParamConstraint is called when we have a .param constraint directive after a class definition
++// 
+ void Assembler::AddGenericParamConstraint(int index, char * pStrGenericParam, mdToken tkTypeConstraint)
+ {
+     if (!m_pCurClass)
+@@ -2545,13 +2554,20 @@ void Assembler::AddGenericParamConstraint(int index, char * pStrGenericParam, md
+             return;
+         }
+     }
+-    bool newlyAdded = CheckAddGenericParamConstraint(&m_pCurClass->m_GPCList, index, tkTypeConstraint);
++
++    // pass true for isParamDirective, we are parsing a .param directive for a class here
++    //
++    CheckAddGenericParamConstraint(&m_pCurClass->m_GPCList, index, tkTypeConstraint, true);
+ }
+
+-// returns true if we create a new GenericParamConstraintDescriptor
+-// reurns false if we return an already existing GenericParamConstraintDescriptor
++// CheckAddGenericParamConstraint is called when we have to handle a generic parameter constariant
++// When parsing a generic class/method definition isParamDirective is false - we have a generic type constaint
++// for this case we do not setup m_pCustomDescrList as a .custom after a generic class/method definition is
++// for the class/method
++// When isParamDirective is true, we have a .param constraint directive and we will setup m_pCustomDescrList
++// and any subsequent .custom is for the generic parameter constrant
+ //
+-bool Assembler::CheckAddGenericParamConstraint(GenericParamConstraintList* pGPCList, int index, mdToken tkTypeConstraint)
++void Assembler::CheckAddGenericParamConstraint(GenericParamConstraintList* pGPCList, int index, mdToken tkTypeConstraint, bool isParamDirective)
+ {
+     _ASSERTE(tkTypeConstraint != 0);
+     _ASSERTE(index >= 0);
+@@ -2578,18 +2594,30 @@ bool Assembler::CheckAddGenericParamConstraint(GenericParamConstraintList* pGPCL
+
+     if (match)
+     {
+-        m_pCustomDescrList = pGPC->CAList();
+-        return false;
++        // Found an existing generic parameter constraint
++        //
++        if (isParamDirective)
++        {
++            // Setup the custom descr list so that we can record
++            // custom attributes on this generic param contraint
++            //
++            m_pCustomDescrList = pGPC->CAList();
++        }
+     }
+     else
+     {
+-        // not found add it to our list
++        // not found - add it to our pGPCList
+         //
+         GenericParamConstraintDescriptor* pNewGPCDescr = new GenericParamConstraintDescriptor();
+         pNewGPCDescr->Init(index, tkTypeConstraint);
+         pGPCList->PUSH(pNewGPCDescr);
+-        m_pCustomDescrList = pNewGPCDescr->CAList();
+-        return true;
++        if (isParamDirective)
++        {
++            // Setup the custom descr list so that we can record
++            // custom attributes on this generic param contraint
++            //
++            m_pCustomDescrList = pNewGPCDescr->CAList();
++        }
+     }
+ }
+
+diff --git a/src/coreclr/src/ilasm/assembler.h b/src/coreclr/src/ilasm/assembler.h
+index 60aa014..8f87df6 100644
+--- a/src/coreclr/src/ilasm/assembler.h
++++ b/src/coreclr/src/ilasm/assembler.h
+@@ -1289,7 +1289,7 @@ public:
+
+     void AddGenericParamConstraint(int index, char * pStrGenericParam, mdToken tkTypeConstraint);
+
+-    bool CheckAddGenericParamConstraint(GenericParamConstraintList* pGPCList, int index, mdToken tkTypeConstraint);
++    void CheckAddGenericParamConstraint(GenericParamConstraintList* pGPCList, int index, mdToken tkTypeConstraint, bool isParamDirective);
+
+     void EmitGenericParamConstraints(int numTyPars, TyParDescr* pTyPars, mdToken tkOwner, GenericParamConstraintList* pGPCL);
+
+diff --git a/src/coreclr/src/ilasm/method.cpp b/src/coreclr/src/ilasm/method.cpp
+index 41df30f..10fd753 100644
+--- a/src/coreclr/src/ilasm/method.cpp
++++ b/src/coreclr/src/ilasm/method.cpp
+@@ -134,6 +134,8 @@ Label *Method::FindLabel(DWORD PC)
+     return NULL;
+ }
+
++// Method::AddGenericParamConstraint is called when we have a .param constraint directive after a method definition
++// 
+ void Method::AddGenericParamConstraint(int index, char * pStrGenericParam, mdToken tkTypeConstraint)
+ {
+     if (index > 0)
+@@ -164,7 +166,10 @@ void Method::AddGenericParamConstraint(int index, char * pStrGenericParam, mdTok
+             return;
+         }
+     }
+-    m_pAssembler->CheckAddGenericParamConstraint(&m_GPCList, index, tkTypeConstraint);
++
++    // pass true for isParamDirective, we are parsing a .param directive for a method here
++    //
++    m_pAssembler->CheckAddGenericParamConstraint(&m_GPCList, index, tkTypeConstraint, true);
+ }
+
+
+-- 
+1.8.3.1
+