Fix DWARF linetable info provided by GDBJIT (dotnet/coreclr#7444)

Extend PC to the end of function in DWARF linetable commands.
This allows the debugger to show source lines for all addresses
inside a function.

Commit migrated from https://github.com/dotnet/coreclr/commit/449feba048bc80faf999ad0e014497fde1d12e60

diff --git a/src/coreclr/src/vm/gdbjit.cpp b/src/coreclr/src/vm/gdbjit.cpp
index d2373f0..1a7f6b1 100644 (file)
--- a/src/coreclr/src/vm/gdbjit.cpp
+++ b/src/coreclr/src/vm/gdbjit.cpp
@@ -752,7 +752,7 @@ void NotifyGdb::MethodCompiled(MethodDesc* MethodDescPtr)
     debugInfoSub.m_sub_low_pc = pCode;
     debugInfoSub.m_sub_high_pc = codeSize;
     /* Build .debug_line section */
-    if (!BuildLineTable(dbgLine, pCode, symInfo, symInfoLen))
+    if (!BuildLineTable(dbgLine, pCode, codeSize, symInfo, symInfoLen))
     {
         return;
     }
@@ -992,7 +992,7 @@ void NotifyGdb::MethodDropped(MethodDesc* MethodDescPtr)
 }
 
 /* Build the DWARF .debug_line section */
-bool NotifyGdb::BuildLineTable(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines, unsigned nlines)
+bool NotifyGdb::BuildLineTable(MemBuf& buf, PCODE startAddr, TADDR codeSize, SymbolsInfo* lines, unsigned nlines)
 {
     MemBuf fileTable, lineProg;
     
@@ -1000,7 +1000,7 @@ bool NotifyGdb::BuildLineTable(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines,
     if (!BuildFileTable(fileTable, lines, nlines))
         return false;
     /* Build line info program */ 
-    if (!BuildLineProg(lineProg, startAddr, lines, nlines))
+    if (!BuildLineProg(lineProg, startAddr, codeSize, lines, nlines))
     {
         return false;
     }
@@ -1147,7 +1147,7 @@ bool NotifyGdb::FitIntoSpecialOpcode(int8_t line_shift, uint8_t addr_shift)
 }
 
 /* Build program for DWARF source line section */
-bool NotifyGdb::BuildLineProg(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines, unsigned nlines)
+bool NotifyGdb::BuildLineProg(MemBuf& buf, PCODE startAddr, TADDR codeSize, SymbolsInfo* lines, unsigned nlines)
 {
     static char cnv_buf[16];
     
@@ -1157,6 +1157,7 @@ bool NotifyGdb::BuildLineProg(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines,
                 + 6                              /* set file command */
                 + nlines * 6                     /* advance line commands */
                 + nlines * (4 + ADDRESS_SIZE)    /* 1 extended + 1 special command */
+                + 6                              /* advance PC command */
                 + 3;                             /* end of sequence command */
     buf.MemPtr = new (nothrow) char[buf.MemSize];
     char* ptr = buf.MemPtr;
@@ -1199,6 +1200,12 @@ bool NotifyGdb::BuildLineProg(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines,
         prevAddr = lines[i].nativeOffset;
     }
     
+    // Advance PC to the end of function
+    if (prevAddr < codeSize) {
+        int len = Leb128Encode(static_cast<uint32_t>(codeSize - prevAddr), cnv_buf, sizeof(cnv_buf));
+        IssueParamCommand(ptr, DW_LNS_advance_pc, cnv_buf, len);
+    }
+
     IssueEndOfSequence(ptr); 
     
     buf.MemSize = ptr - buf.MemPtr;

diff --git a/src/coreclr/src/vm/gdbjit.h b/src/coreclr/src/vm/gdbjit.h
index 7f87d9e..21a60fe 100644 (file)
--- a/src/coreclr/src/vm/gdbjit.h
+++ b/src/coreclr/src/vm/gdbjit.h
@@ -141,9 +141,9 @@ private:
                                NewArrayHolder<LocalsDebugInfo>& localsDebug,
                                unsigned int localsDebugSize);
     static bool BuildDebugPub(MemBuf& buf, const char* name, uint32_t size, uint32_t dieOffset);
-    static bool BuildLineTable(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines, unsigned nlines);
+    static bool BuildLineTable(MemBuf& buf, PCODE startAddr, TADDR codeSize, SymbolsInfo* lines, unsigned nlines);
     static bool BuildFileTable(MemBuf& buf, SymbolsInfo* lines, unsigned nlines);
-    static bool BuildLineProg(MemBuf& buf, PCODE startAddr, SymbolsInfo* lines, unsigned nlines);
+    static bool BuildLineProg(MemBuf& buf, PCODE startAddr, TADDR codeSize, SymbolsInfo* lines, unsigned nlines);
     static bool FitIntoSpecialOpcode(int8_t line_shift, uint8_t addr_shift);
     static void IssueSetAddress(char*& ptr, PCODE addr);
     static void IssueEndOfSequence(char*& ptr);