From feb54379427093dca566cbea996e7a57b80d73eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9Cjimihe=E2=80=9D?= <jimihe@glenfly.com>
Date: Thu, 23 Nov 2023 14:19:58 +0800
Subject: [PATCH] PP: Report an error when a # is not the first thing on a line

According to the GLSL spec
Each number sign (#) can be preceded in its line only by spaces or horizontal tabs.
It may also be followed by spaces and horizontal tabs, preceding the directive.
---
 Test/baseResults/cppBad.vert.out              |  4 ++-
 Test/baseResults/cppBad4.vert.out             |  3 +-
 .../preprocessor/PpContext.h                  | 32 +++++++++++++++++--
 3 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/Test/baseResults/cppBad.vert.out b/Test/baseResults/cppBad.vert.out
index 8ab04bc0..e0a1504a 100644
--- a/Test/baseResults/cppBad.vert.out
+++ b/Test/baseResults/cppBad.vert.out
@@ -1,5 +1,7 @@
 cppBad.vert
 WARNING: 0:1: '#define' : missing space after macro name 
+ERROR: 0:1: '#' : (#) can be preceded in its line only by spaces or horizontal tabs 
+ERROR: 0:2: '#' : (#) can be preceded in its line only by spaces or horizontal tabs 
 ERROR: 0:3: 'preprocessor evaluation' : bad expression 
 ERROR: 0:3: '#if' : unexpected tokens following directive 
 ERROR: 0:6: 'string' : End of line in string 
@@ -7,7 +9,7 @@ ERROR: 0:6: 'string literal' : required extension not requested: Possible extens
 GL_EXT_debug_printf
 GL_EXT_spirv_intrinsics
 ERROR: 0:6: '' :  syntax error, unexpected INT, expecting COMMA or SEMICOLON
-ERROR: 5 compilation errors.  No code generated.
+ERROR: 7 compilation errors.  No code generated.
 
 
 Shader version: 100
diff --git a/Test/baseResults/cppBad4.vert.out b/Test/baseResults/cppBad4.vert.out
index 693ea8e8..23f149db 100644
--- a/Test/baseResults/cppBad4.vert.out
+++ b/Test/baseResults/cppBad4.vert.out
@@ -1,7 +1,8 @@
 cppBad4.vert
+ERROR: 0:2: '#' : (#) can be preceded in its line only by spaces or horizontal tabs 
 ERROR: 0:4: 'macro expansion' : unexpected '#' g
 ERROR: 0:5: '' :  syntax error, unexpected SEMICOLON, expecting LEFT_PAREN
-ERROR: 2 compilation errors.  No code generated.
+ERROR: 3 compilation errors.  No code generated.
 
 
 Shader version: 100
diff --git a/glslang/MachineIndependent/preprocessor/PpContext.h b/glslang/MachineIndependent/preprocessor/PpContext.h
index 18342bf6..1ec30491 100644
--- a/glslang/MachineIndependent/preprocessor/PpContext.h
+++ b/glslang/MachineIndependent/preprocessor/PpContext.h
@@ -215,6 +215,7 @@ public:
         virtual bool peekContinuedPasting(int) { return false; } // true when non-spaced tokens can paste
         virtual bool endOfReplacementList() { return false; } // true when at the end of a macro replacement list (RHS of #define)
         virtual bool isMacroInput() { return false; }
+        virtual bool isStringInput() { return false; }
 
         // Will be called when we start reading tokens from this instance
         virtual void notifyActivated() {}
@@ -355,7 +356,8 @@ protected:
     // Scanner data:
     int previous_token;
     TParseContextBase& parseContext;
-
+    std::vector<int> lastLineTokens;
+    std::vector<TSourceLoc> lastLineTokenLocs;
     // Get the next token from *stack* of input sources, popping input sources
     // that are out of tokens, down until an input source is found that has a token.
     // Return EndOfInput when there are no more tokens to be found by doing this.
@@ -369,7 +371,31 @@ protected:
                 break;
             popInput();
         }
-
+        if (!inputStack.empty() && inputStack.back()->isStringInput()) {
+            if (token == '\n') {
+                bool seenNumSign = false;
+                for (int i = 0; i < (int)lastLineTokens.size() - 1;) {
+                    int curPos = i;
+                    int curToken = lastLineTokens[i++];
+                    if (curToken == '#' && lastLineTokens[i] == '#') {
+                        curToken = PpAtomPaste;
+                        i++;
+                    }
+                    if (curToken == '#') {
+                        if (seenNumSign) {
+                            parseContext.ppError(lastLineTokenLocs[curPos], "(#) can be preceded in its line only by spaces or horizontal tabs", "#", "");
+                        } else {
+                            seenNumSign = true;
+                        }
+                    }
+                }
+                lastLineTokens.clear();
+                lastLineTokenLocs.clear();
+            } else {
+                lastLineTokens.push_back(token);
+                lastLineTokenLocs.push_back(ppToken->loc);
+            }
+        }
         return token;
     }
     int  getChar() { return inputStack.back()->getch(); }
@@ -522,7 +548,7 @@ protected:
     public:
         tStringInput(TPpContext* pp, TInputScanner& i) : tInput(pp), input(&i) { }
         virtual int scan(TPpToken*) override;
-
+        bool isStringInput() override { return true; }
         // Scanner used to get source stream characters.
         //  - Escaped newlines are handled here, invisibly to the caller.
         //  - All forms of newline are handled, and turned into just a '\n'.