From 149d16d8fc9fb05ce250bd770a67606dfc9c7031 Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Thu, 10 Oct 2019 19:00:49 -0400
Subject: [PATCH] add support for `line directive

---
 src/Language/SystemVerilog/Parser/Lex.x | 37 ++++++++++++++++++++++---
 test/lex/file_line.sv                   |  7 +++++
 test/lex/line.sv                        |  7 +++++
 test/lex/line.v                         |  7 +++++
 4 files changed, 54 insertions(+), 4 deletions(-)
 create mode 100644 test/lex/line.sv
 create mode 100644 test/lex/line.v

diff --git a/src/Language/SystemVerilog/Parser/Lex.x b/src/Language/SystemVerilog/Parser/Lex.x
index b709bc8..b46168d 100644
--- a/src/Language/SystemVerilog/Parser/Lex.x
+++ b/src/Language/SystemVerilog/Parser/Lex.x
@@ -529,12 +529,10 @@ lexFile includePaths env path = do
             where finalToks = coalesce $ reverse $ lsToks finalState
     where
         setEnv = do
-            -- standardize the file path format
-            path' <- includeSearch path
             modify $ \s -> s
                 { lsEnv = env
                 , lsIncludePaths = includePaths
-                , lsCurrFile = path'
+                , lsCurrFile = path
                 }
 
 -- combines identifiers and numbers that cross macro boundaries
@@ -716,6 +714,27 @@ takeQuotedString = do
         then lexicalError $ "library includes are not supported: " ++ res
         else return res
 
+-- removes and returns a decimal number
+takeNumber :: Alex Int
+takeNumber = do
+    dropSpaces
+    leadCh <- peekChar
+    if '0' <= leadCh && leadCh <= '9'
+        then step 0
+        else lexicalError $ "expected number, but found unexpected char: "
+                ++ show leadCh
+    where
+        step number = do
+            ch <- takeChar
+            if ch == ' ' || ch == '\n' then
+                return number
+            else if '0' <= ch && ch <= '9' then do
+                let digit = ord ch - ord '0'
+                step $ number * 10 + digit
+            else
+                lexicalError $ "unexpected char while reading number: "
+                    ++ show ch
+
 peekChar :: Alex Char
 peekChar = do
     (_, _, _, str) <- alexGetInput
@@ -881,6 +900,16 @@ handleDirective (posOrig, _, _, strOrig) len = do
             modify $ push $ Token Lit_number tokStr tokPos
             alexMonadScan
 
+        "line" -> do
+            lineNumber <- takeNumber
+            quotedFilename <- takeQuotedString
+            _ <- takeNumber -- level, ignored
+            let filename = init $ tail quotedFilename
+            setCurrentFile filename
+            (AlexPn f _ c, prev, _, str) <- alexGetInput
+            alexSetInput (AlexPn f (lineNumber + 1) c, prev, [], str)
+            alexMonadScan
+
         "include" -> do
             quotedFilename <- takeQuotedString
             inputFollow <- alexGetInput
@@ -968,7 +997,7 @@ handleDirective (posOrig, _, _, strOrig) len = do
                     currToks <- gets lsToks
                     modify $ \s -> s { lsToks = [] }
                     -- lex the macro expansion, preserving the file and line
-                    alexSetInput (AlexPn 0 l 0, ' ' , [], replacement)
+                    alexSetInput (AlexPn 0 l 0, ' ', [], replacement)
                     alexMonadScan
                     -- re-tag and save tokens from the macro expansion
                     newToks <- gets lsToks
diff --git a/test/lex/file_line.sv b/test/lex/file_line.sv
index 2fc4164..ee119ed 100644
--- a/test/lex/file_line.sv
+++ b/test/lex/file_line.sv
@@ -1,3 +1,8 @@
+`ifndef INCLUDED
+`define INCLUDED
+`include "file_line.sv"
+`else
+
 `define MACRO(arg) $display(arg, `__FILE__, `__LINE__);
 `define MACRO_NO_ARG $display(`__FILE__, `__LINE__);
 module top;
@@ -14,3 +19,5 @@ initial begin
     `MACRO("f")
 end
 endmodule
+
+`endif
diff --git a/test/lex/line.sv b/test/lex/line.sv
new file mode 100644
index 0000000..7cd0946
--- /dev/null
+++ b/test/lex/line.sv
@@ -0,0 +1,7 @@
+module top;
+    initial begin
+        $display(`__FILE__, `__LINE__);
+`line 101 "fake.v" 1
+        $display(`__FILE__, `__LINE__);
+    end
+endmodule
diff --git a/test/lex/line.v b/test/lex/line.v
new file mode 100644
index 0000000..0e5df5c
--- /dev/null
+++ b/test/lex/line.v
@@ -0,0 +1,7 @@
+module top;
+    initial begin
+        $display("line.sv", `__LINE__);
+        ;
+        $display("fake.v", 102);
+    end
+endmodule