[x86/Linux][SOS] Fix clrstack command of lldb sosplugin on x86 (#13973)

* [x86/Linux][SOS] Add support for x86 in GetContextFromFrame

It's need for 'clrstack -f' command of SOS plugin on x86.

* [x86/Linux] Fix RtlpGetFunctionEndAddress function

We should use PTR_UNWIND_INFO instead of PUNWIND_INFO for pointer to
UNWIND_INFO structure because it's pointer from other process and
we need to use DAC to read data using it.

* [x86/Linux][SOS] Define DEBUG_STACK_CONTEXT for x86

It's needed for 'clrstack -f' command in libsosplugin.

* [x86/Linux] Fix undefined references in libmscordbi.so on x86

Asm block like following:
__asm fnsave currentFPUState

where currentFPUState is structure works with MSVC but leads to
undefined reference currentFPUState in the binary with other
compilers. So rewrite such asm blocks for them.

This patch fixes error "Unable to load 'libmscordbi.so'" during
execution of 'clrstack -f' command of SOS plugin on x86.

* [x86/Linux] Fix calling convention inconsistency

WINAPI and STDAPI are defined as __cdecl but in some cases functions
with these attributes are called using stdcall calling convention.

It leads to crashes during execution of 'clrstack -i' command of
SOS plugin on x86.

7 files changed, 91 insertions, 6 deletions

diff --git a/src/ToolBox/SOS/Strike/strike.cpp b/src/ToolBox/SOS/Strike/strike.cpp
index 6963cffe29..5ab45d5dca 100644
--- a/src/ToolBox/SOS/Strike/strike.cpp
+++ b/src/ToolBox/SOS/Strike/strike.cpp
@@ -324,7 +324,9 @@ DECLARE_API(IP2MD)
 #define DEBUG_STACK_CONTEXT AMD64_CONTEXT
 #elif defined(_TARGET_ARM_) // _TARGET_WIN64_
 #define DEBUG_STACK_CONTEXT ARM_CONTEXT
-#endif // _TARGET_ARM_
+#elif defined(_TARGET_X86_) // _TARGET_ARM_
+#define DEBUG_STACK_CONTEXT X86_CONTEXT
+#endif // _TARGET_X86_
 
 #ifdef DEBUG_STACK_CONTEXT
 // I use a global set of frames for stack walking on win64 because the debugger's
diff --git a/src/ToolBox/SOS/lldbplugin/services.cpp b/src/ToolBox/SOS/lldbplugin/services.cpp
index d0ea7bced9..3186920eb0 100644
--- a/src/ToolBox/SOS/lldbplugin/services.cpp
+++ b/src/ToolBox/SOS/lldbplugin/services.cpp
@@ -1577,6 +1577,25 @@ LLDBServices::GetContextFromFrame(
     dtcontext->R10 = GetRegister(frame, "r10");
     dtcontext->R11 = GetRegister(frame, "r11");
     dtcontext->R12 = GetRegister(frame, "r12");
+#elif DBG_TARGET_X86
+    dtcontext->Eip = frame.GetPC();
+    dtcontext->Esp = frame.GetSP();
+    dtcontext->Ebp = frame.GetFP();
+    dtcontext->EFlags = GetRegister(frame, "eflags");
+
+    dtcontext->Edi = GetRegister(frame, "edi");
+    dtcontext->Esi = GetRegister(frame, "esi");
+    dtcontext->Ebx = GetRegister(frame, "ebx");
+    dtcontext->Edx = GetRegister(frame, "edx");
+    dtcontext->Ecx = GetRegister(frame, "ecx");
+    dtcontext->Eax = GetRegister(frame, "eax");
+
+    dtcontext->SegCs = GetRegister(frame, "cs");
+    dtcontext->SegSs = GetRegister(frame, "ss");
+    dtcontext->SegDs = GetRegister(frame, "ds");
+    dtcontext->SegEs = GetRegister(frame, "es");
+    dtcontext->SegFs = GetRegister(frame, "fs");
+    dtcontext->SegGs = GetRegister(frame, "gs");
 #endif
 }
 
diff --git a/src/debug/di/rsthread.cpp b/src/debug/di/rsthread.cpp
index 02fae00b0f..aa85de83d8 100644
--- a/src/debug/di/rsthread.cpp
+++ b/src/debug/di/rsthread.cpp
@@ -1471,7 +1471,15 @@ void CordbThread::Get32bitFPRegisters(CONTEXT * pContext)
 
     FLOATING_SAVE_AREA currentFPUState;
 
+#ifdef _MSC_VER
     __asm fnsave currentFPUState // save the current FPU state.
+#else
+    __asm__ __volatile__
+    (
+        "  fnsave %0\n" \
+        : "=m"(currentFPUState)
+    );
+#endif
 
     floatarea.StatusWord &= 0xFF00; // remove any error codes.
     floatarea.ControlWord |= 0x3F; // mask all exceptions.
@@ -1482,12 +1490,22 @@ void CordbThread::Get32bitFPRegisters(CONTEXT * pContext)
     // @dbgtodo Microsoft crossplat: the conversion from a series of bytes to a floating 
     // point value will need to be done with an explicit conversion routine to unpack
     // the IEEE format and compute the real number value represented. 
-    
+
+#ifdef _MSC_VER
     __asm
     {
         fninit
         frstor floatarea          ;; reload the threads FPU state.
     }
+#else
+    __asm__
+    (
+        "  fninit\n" \
+        "  frstor %0\n" \
+        : /* no outputs */
+        : "m"(floatarea)
+    );
+#endif
 
     unsigned int i;
 
@@ -1498,11 +1516,21 @@ void CordbThread::Get32bitFPRegisters(CONTEXT * pContext)
         m_floatValues[i] = td;
     }
 
+#ifdef _MSC_VER
     __asm
     {
         fninit
         frstor currentFPUState    ;; restore our saved FPU state.
     }
+#else
+    __asm__
+    (
+        "  fninit\n" \
+        "  frstor %0\n" \
+        : /* no outputs */
+        : "m"(currentFPUState)
+    );
+#endif
 
     m_fFloatStateValid = true;
     m_floatStackTop = floatStackTop;
diff --git a/src/debug/di/valuehome.cpp b/src/debug/di/valuehome.cpp
index 837afd5f8b..6cae8c1f3a 100644
--- a/src/debug/di/valuehome.cpp
+++ b/src/debug/di/valuehome.cpp
@@ -481,18 +481,36 @@ void FloatRegValueHome::SetEnregisteredValue(MemoryRange newValue,
     // restore our original state.
     DT_FLOATING_SAVE_AREA currentFPUState;
 
+    #ifdef _MSC_VER
     __asm fnsave currentFPUState // save the current FPU state.
+    #else
+    __asm__ __volatile__
+    (
+        "  fnsave %0\n" \
+        : "=m"(currentFPUState)
+    );
+    #endif
 
     // Copy the state out of the context.
     DT_FLOATING_SAVE_AREA floatarea = pContext->FloatSave;
     floatarea.StatusWord &= 0xFF00; // remove any error codes.
     floatarea.ControlWord |= 0x3F; // mask all exceptions.
 
+    #ifdef _MSC_VER
     __asm
     {
         fninit
         frstor floatarea          ;; reload the threads FPU state.
     }
+    #else
+    __asm__
+    (
+        "  fninit\n" \
+        "  frstor %0\n" \
+        : /* no outputs */
+        : "m"(floatarea)
+    );
+    #endif
 
     double td; // temp double
     double popArea[DebuggerIPCE_FloatCount];
@@ -519,17 +537,35 @@ void FloatRegValueHome::SetEnregisteredValue(MemoryRange newValue,
     }
 
     // Save out the modified float area.
+    #ifdef _MSC_VER
     __asm fnsave floatarea
+    #else
+    __asm__ __volatile__
+    (
+        "  fnsave %0\n" \
+        : "=m"(floatarea)
+    );
+    #endif
 
     // Put it into the context.
     pContext->FloatSave= floatarea;
 
     // Restore our FPU state
+    #ifdef _MSC_VER
     __asm
     {
         fninit
         frstor currentFPUState    ;; restore our saved FPU state.
     }
+    #else
+    __asm__
+    (
+        "  fninit\n" \
+        "  frstor %0\n" \
+        : /* no outputs */
+        : "m"(currentFPUState)
+    );
+    #endif
     #endif // DBG_TARGET_X86
 
     // update the thread's floating point stack
diff --git a/src/debug/shim/debugshim.cpp b/src/debug/shim/debugshim.cpp
index 03b9c5f550..08f1ec58a1 100644
--- a/src/debug/shim/debugshim.cpp
+++ b/src/debug/shim/debugshim.cpp
@@ -38,7 +38,7 @@
 // CLRDebuggingImpl implementation (ICLRDebugging)
 //*****************************************************************************
 
-typedef HRESULT (__stdcall  *OpenVirtualProcessImplFnPtr)(ULONG64 clrInstanceId, 
+typedef HRESULT (STDAPICALLTYPE  *OpenVirtualProcessImplFnPtr)(ULONG64 clrInstanceId, 
     IUnknown * pDataTarget,
     HMODULE hDacDll,
     CLR_DEBUGGING_VERSION * pMaxDebuggerSupportedVersion,
@@ -46,7 +46,7 @@ typedef HRESULT (__stdcall  *OpenVirtualProcessImplFnPtr)(ULONG64 clrInstanceId,
     IUnknown ** ppInstance,
     CLR_DEBUGGING_PROCESS_FLAGS * pdwFlags);
 
-typedef HRESULT (__stdcall  *OpenVirtualProcess2FnPtr)(ULONG64 clrInstanceId, 
+typedef HRESULT (STDAPICALLTYPE  *OpenVirtualProcess2FnPtr)(ULONG64 clrInstanceId, 
     IUnknown * pDataTarget,
     HMODULE hDacDll,
     REFIID riid,
diff --git a/src/dlls/mscordbi/mscordbi.cpp b/src/dlls/mscordbi/mscordbi.cpp
index 4ef92c7ee8..0197d13d06 100644
--- a/src/dlls/mscordbi/mscordbi.cpp
+++ b/src/dlls/mscordbi/mscordbi.cpp
@@ -11,7 +11,7 @@
 //*****************************************************************************
 #include "stdafx.h"
 
-extern BOOL STDMETHODCALLTYPE DbgDllMain(HINSTANCE hInstance, DWORD dwReason,
+extern BOOL WINAPI DbgDllMain(HINSTANCE hInstance, DWORD dwReason,
                                          LPVOID lpReserved);
 
 //*****************************************************************************
diff --git a/src/inc/clrnt.h b/src/inc/clrnt.h
index ebea066663..487a370d02 100644
--- a/src/inc/clrnt.h
+++ b/src/inc/clrnt.h
@@ -862,7 +862,7 @@ RtlpGetFunctionEndAddress (
     __in TADDR ImageBase
     )
 {
-    PUNWIND_INFO pUnwindInfo = (PUNWIND_INFO)(ImageBase + FunctionEntry->UnwindData);
+    PTR_UNWIND_INFO pUnwindInfo = (PTR_UNWIND_INFO)(ImageBase + FunctionEntry->UnwindData);
 
     return FunctionEntry->BeginAddress + pUnwindInfo->FunctionLength;
 }